Search

The importance of ensuring the inherent safety and security has been more emphasized in recent years to demonstrate the integrity of nuclear facilities under external human-induced events (e.g. aircraft crashes). This work suggests a simulation methodology to effectively evaluate the impact of a commercial aircraft engine onto a dry storage facility. A full-scale engine model was developed and verified by Riera force-time history analysis. A reinforced concrete (RC) structure of a dry storage facility was also developed and material behavior of concrete was incorporated using three constitutive models namely: Continuous Surface Cap, Winfrith, and Karagozian & Case for comparison. Strain-based erosion limits for concrete were suitably defined and the local responses were then compared and analyzed with empirical formulas according to variations in impact velocity. The proposed methodology reasonably predicted such local damage modes of RC structure from the engine missile, and the analysis results agreed well with the calculations of empirical formulas. This research is expected to be helpful in reviewing the dry storage facility design and in the probabilistic risk assessment considering diverse impact scenarios.

This research aims to measure the awareness of chefs towards the hierarchy of food storage and analyze the differences between their awareness based on their demographic data. Literature review includes some topics about food storage in the restaurant such as dry storage, chemical storage, refrigerator storage, and freezer storage, food contamination during food storage, preventing cross-contamination during storage, food contaminations and their impact on health, food hierarchy chart in a restaurant, and chefs’ awareness towards food hierarchy. For achieving the research aim, an electronic questionnaire (as a test) was designed and distributed to a random sample of chefs in Egyptian restaurants, which 447 responses were received and valid to analyze by SPSS V.25. Results indicated that investigated chefs haven’t enough awareness of food hierarchy storage. Some chefs store food in the wrong arrangement that leads to rapid spoilage or cross-contamination. Based on the results, some recommendations have been proposed to increase the awareness of chefs towards food hierarchy storage. One of the most important recommendations was putting guidelines and instructions in clear places within each store that directs chefs on how to arrange food properly.

Purpose To investigate optic opacification of hydrophobic acrylic intraocular lens (IOL) depending on hydration and temperature conditions. Methods IOL (Acrysof® MA60BM Alcon, Fort Worth, Texas, USA) extracted from a 55-year-old male who underwent binocular cataract 11 years ago were used for the analysis. On slit lamp examination, the binocular IOL optics showed homogenous opacification. After extraction of the IOLs, the IOL opacification disappeared during dry storage at 4°C. To investigate the changes in IOL opacification according to temperature and hydration, an extracted IOL was stored in either dry conditions or normal saline at 4°C, room temperature, or 37°C for 24 hours, and then the degree of haziness was examined. To investigate the impact of an opaque optic on visual function, light transmission was performed using an ultraviolet-visible spectrophotometer (U-3000, Hitachi High-Technologies Corp., Tokyo, Japan). Results The extracted IOL optics at 4°C, room temperature, and 37°C were transparent at dry conditions. When the dried IOL was immersed in normal saline at room temperature and 37°C, opacification appeared. However, when the dried IOL was immersed in normal saline at 4°C, opacification of the IOL did not appear. When compared with the control, light transmission of the extracted IOLs from the right and left eyes stored in 37°C normal saline decreased by 4.7% at 453 nm and by 5.1% at 482 nm, respectively. Conclusion In acrylic hydrophobic IOLs, optic opacification can occur depending on temperature and hydration conditions.

Nükleer güç santrallerinin kullanılmış yakıtlarının yönetiminde izlenebilecek iki yöntem mevcuttur. Kullanılmış yakıt yeniden işlenebilir veya jeolojik yapılarda bertaraf edilebilir. Ancak, günümüzde jeolojik bertaraf henüz gerçekleştirilemediği için kullanılmış yakıtlar uzun süreli depolanmaktadır. Bu çalışmada, dört adet VVER-1200 tipi reaktör ünitesi içeren bir nükleer güç santralinin işletilmesi sırasında oluşacak kullanılmış yakıtlar için depolama tesisi modeli geliştirilmiş ve iki farklı depolama senaryosunun uygulanması durumunda tesisin yaşam döngüsü maliyeti analiz edilmiştir. Çalışmanın ilk bölümünde, işletme ömrü boyunca santralden çıkarılacak kullanılmış yakıt miktarı belirlenmiştir. Daha sonra, hesaplanan kullanılmış yakıt envanterinin depolanması için bir depolama tesisi modeli geliştirilmiş ve depolama varilinin tipi, malzemesi, depolama alanı büyüklüğü gibi tesisin temel özellikleri belirlenmiştir. Son olarak, iki farklı depolama senaryosunun uygulanması durumunda “net şimdiki değer” ve “seviyelendirilmiş birim maliyet” yöntemleri kullanılarak tesis için yaşam döngüsü maliyet analizi yapılmıştır. There are two methods to be applied in the management of spent fuels of nuclear power plants. Spent fuel can be reprocessed or disposed of in geological formations. However, since the geological disposal has not been realized yet, spent fuels are stored for a long time. In this study, a storage facility model has been developed for spent fuels of a nuclear power plant containing four VVER-1200 units and life cycle cost analysis of the facility has been performed for two storage scenarios. In the first part of the study, the amount of spent fuel to be discharged from the plant during its operational life is determined. Then, a storage facility model is developed for the storage of estimated spent fuel inventory and basic characteristics of the facility such as storage cask type, material, storage area is determined. Finally, life cycle cost analysis of the facility is performed for two storage scenarios by using “net present value” and “levelised unit cost” methods.

Proper storage prolongs peony market supply. Here, we determined the changes in fresh weight and expression of four aquaporin genes under dry storage (DS) and wet storage (WS). It has showed that after harvesting, the fresh weight change was accompanied with flower opening. After both short- and long-term of storage, the water uptake efficiency in DS group was greater during the first few vase days, providing a direct material basis of DS improved vase quality. The gene expression results showed that PlPIP1;3 and PlTIP2;1 were mainly expressed in petals, whereas PlNIP1;2-like and PlSIP2;1 were mainly expressed in the green tissues. In addition, the expression of PlTIP2;1 in the petals was consistent with the flower opening process, indicating that it may play a major role in facilitating water uptake. During cold storage, the expression of PlPIP1;3 and PlTIP2;1 was higher or more rapidly induced in the DS group, and thus we deduced that they play important roles in improving the vase quality of DS. Furthermore, the expression of PlNIP1;2-like in the early stage of the DS group was more stable than in WS, which may also be partially responsible for the vase quality improvement. In contrast, PlSIP2;1 may not be involved, since no significant change was observed between the DS and WS group. In short, the expression of PlPIP1;3 and PlTIP2;1 in the DS group during storage may improve water uptake efficiency during the vase period and then improving the vase quality of cut peony.

Dental trauma resulting in permanent tooth avulsion commonly affects the young population. The prognosis of replantation after avulsion depends on the natural history of inflammatory and replacement resorption. Several risk factors for type and onset of external resorption have been defined. This case study describes different resorptive patterns observed in two upper central incisors belonging to a single individual, avulsed in the same moment, and replanted after thirty-six hours of dry storage. The roots were analyzed by scanning electron microscopy and stereomicroscope imaging, to obtain an in-depth analysis of the resorptive pattern. The aim of this report is to: (i) underline the high variability in the incidence of root resorption after replantation across and within types of teeth and resorption; and (ii) underline the possible concurrence of different factors affecting the onset and type of resorptive pattern. In conclusion, an unpredictable pattern of resorption may account for the poor prognosis when teeth are replanted outside the current recommendations.

This paper describes development and demonstration of nondestructive examination (NDE) technologies to support periodic examinations of interim dry storage system (DSS) canisters for spent nuclear fuel in the USA to verify continued safe operation and that the canister confinement is intact and performing its intended safety function. Specifically, this work relates to NDE technology development for “canister” based DSS systems, which form the majority population of DSSs in the USA for interim storage of spent nuclear fuel. Consideration of potential degradation of the welded stainless-steel canister in these systems is required for continued usage in the period of extended operation (PEO) beyond the initial license or certified term. Physical access to the canister surface is constrained due to narrow annulus spaces between the canister and the overpack, tortuous entry pathways, and high temperatures and radiation doses that can be damaging to materials and electronics related to inspections. Several activities to demonstrate NDE technologies for the inspections of different DSS systems are summarized.

This paper describes development and demonstration of remote crawling systems to support periodic examinations of interim dry storage system (DSS) canisters for spent nuclear fuel in the USA. Specifically, this work relates to robotic crawler developments for “canister” based DSS systems, which form the majority population of DSSs in the USA for interim storage of spent nuclear fuel. Consideration of potential degradation of the welded stainless-steel canister in these systems is required for continued usage in the period of extended operation (PEO) beyond their initial licensed or certified terms. Challenges with performing the periodic examinations are associated with physical access to the canister surface, which is constrained due to narrow annulus spaces between the canister and the overpack, tortuous entry pathways, and high temperatures and radiation doses that can be damaging to materials and electronics. Motivations for performing periodic examinations and developing robotic crawlers for performing those examinations remotely will be presented, and several activities to demonstrate robotic crawlers for different DSS systems are summarized.

Since the 1970s, aircraft crash accidents have been considered as one of the severest external events that should be evaluated for license application of nuclear reactors. After the 9.11 terrorist attacks, many countries have performed safety assessment against intentional or targeted aircraft crashes into nuclear related facilities. In some countries, assessment against targeted aircraft crash was enforced by regulation and considered an important task for license approval. Safety assessment against aircraft crash is a technically difficult task and many countries manage R&D programs to improve its reliability. In this paper, regulations of many countries regarding safety assessment against aircraft crash are summarized, separating regulations for accident aircraft crash and those for targeted aircraft crash. Research performed in various countries on safety assessment of nuclear facility against aircraft crash are summarized, with a focus on spent nuclear fuel dry storage facilities.

Purpose This study aimed to evaluate periodontal and pulpal healing in replanted rat teeth, preserved under different storage conditions, with or without root conditioning using doxycycline. Methods A total of 40 maxillary first molars extracted from 20 Sprague-Dawley rats were stored for different durations under different conditions (5 minutes in dry storage and 60 minutes in Hank's balanced salt solution [HBSS]) and subsequently replanted. The rats were divided into 2 groups based on the use of root surface treatment: the doxycycline group (root surface treated with doxycycline) and the control group (no doxycycline treatment). Eight weeks after replantation, the animals were sacrificed, and the teeth were evaluated using micro-computed tomography (micro-CT) and histomorphometric analysis. Results In the micro-CT analysis, the doxycycline group showed the same rate of occurrence of periapical radiolucency as was observed in the control group, but a lower degree of root resorption in teeth replanted after 60 minutes of storage in HBSS (P, Graphical Abstract

The microbial quality of food contact surfaces in the food preparation facilities is an indication of their hygiene status. The objective of this study was to assess the hygiene status and the incidence of pathogens of food contact surfaces in the food preparation facilities of schools offering school feeding programs in the Mpumalanga Province, South Africa. 192 swab samples were collected by swabbing 100 cm2 areas of food contact surfaces in the food preparation facilities of randomly selected schools. Only 16.2% of the food contact surfaces had satisfactory hygiene status in which the surface aerobic colony counts were less than 2 log cfu/cm2. Only 3% and 6% of the benchtop and dry storage surfaces respectively had a satisfactory hygiene status. Listeria monocytogenes and Staphylococcus aureus were the most detected pathogen on food contact surfaces with 53.1% and 25.5% incidences. There was a strong significant positive correlation between the occurrence of L. monocytogenes on dry storage surfaces and benchtop (rho = 0.539**, p = 0.01), cutting board (rho = 0.541**, p = 0.01), refrigerator handle (rho = 0.420*, p = 0.05), and sink faucet (rho = 0.498**, p = 0.01) surfaces. The Bacillus species was generally detected the most from aerobic growth isolates of food contact sources, among which Bacillus subtilis was the most abundant species identified. Most of the food contact surfaces in the food preparation facilities of schools offering school feeding programs were of unsatisfactory hygiene status and constituted a food safety risk to schoolchildren consuming meals at school.

Extended dry storage of spent nuclear fuel is a relevant issue in many countries operating nuclear power plants. Beside regulatory and security aspects there are questions with respect to the long-term integrity of the spent fuel as this is of relevance for final transportation and reloading to final waste repository casks. Within the frame of the BMWi project DCS-MONITOR, we investigate the potentials of different methods for non-intrusive monitoring of dry cask storage containers with spent nuclear fuel. These are thermography, radiation-based methods, and acoustic methods. For all of them we study the sensitivity and cross-sensitivity with respect to defined changes in the nuclear fuel distribution inside the containers. The analyses are mainly based on numerical simulations but also include some dedicated experimental studies.

Purpose To evaluate the effects of overnight storage conditions on the dimensional stability and retention of prostheses, as well as the participant's subjective perception of these interventions. Materials and methods Subjects with maxillary complete prostheses (CRPs) were randomly assigned to receive two interventions in a crossover design: storing the CRPs overnight in a dry or wet environment with a cleansing tablet. The denture intaglio surface was scanned, and outcome measures were collected before each intervention (BLN), post ntervention (PIS), and after immersion in water for 15 minutes after the intervention (WOC). Dimensional changes were analyzed for the total surface, anterior flange, palate, and tuberosities. Retention force was measured using a dynamometer, and the participants' subjective assessment of comfort, fit, and retention of their CRPs were collected. After verifying normal distribution, paired t and Wilcoxon signed-rank tests were used to check for any statistical significance (α = .05). Results Ten participants (mean age: 76.5 ± 5.9 y) were recruited in this study. Between BLN and PIS, the dimensional changes after dry intervention were significantly less than when stored wet for total surface (P = .009), anterior flange (P = .028), and the palate (P = .005). No difference was found between the effects of storage or washout interventions on objectively measured CRP retention. However, after WOC following dry storage, participants perceived a lower retention (P = .021), and a more comfortable palate after WOC following the wet intervention (P = .018). Conclusion For dimensional stability, dry overnight storage of removable prostheses can safely be recommended when indicated. Immersion in water for 15 minutes does not seem to add advantages.

Biobanking has traditionally encompassed the collection, processing, and storage of biological samples and other specimens from environmental sources. Most of the procedures currently used by biobanks have involved processing tissue and blood samples. Formalin-fixation of tissue samples and storage at ambient temperature, and freezing blood fractions are the normal methodologies. However, recent developments in biospecimen management promise to revolutionize biobanking. Economic pressures have resulted in new storage technologies, including dry storage, which promise to reduce the high cost of freezer storage. New analysis platforms including genome-wide association studies and metabolomics have altered biospecimen processing schemes. Sample types have evolved to include circulating tumor cells and induced pluripotent stem cells. These developments will lead to the need for additional methods to assure their proper processing and storage for translational research studies. As these new developments evolve and international collaborations continue to grow, there will be an additional need to coordinate best practices and continue to perform biospecimen methods research to develop evidence-based practices. In addition to technical aspects, there are serious ethical and regulatory concerns that will require additional guidance, including consideration of issues around the return of research results to biospecimen donors, and reporting incidental clinical findings.

Introduction: Alternative methods of dry storage and transportation may be a viable alternative to the use of liquid storage medium for cervical samples, especially for screening programs in places with few resources. Objective: The objective of this study is to verify the viability and efficacy of human papillomavirus DNA (HPV-DNA) detection in cervical cell samples collected and stored on a Flinders Technology Associates (FTA) card (Whatman Indicating FTA® Elute Micro Card) and subsequently recovered in ethanol-based liquid medium and to compare the results to those obtained using samples stored directly in ethanol-based liquid medium. Study Design: Thirty-four women submitted to ETZ (excision of the transformation zone of the cervix) were included in this study. Before ETZ, 2 samples of exfoliated cervical cells were collected from each woman by a doctor and stored in ethanol-based liquid medium and on an FTA card. DNA recovery from FTA samples was performed using ethanol-based liquid medium. Detection of HPV-DNA in the samples was performed using the Cobas® 4800 HPV Test Platform. Results and Conclusions: The HPV-DNA detection positivity rates were 70.6% for the samples collected directly in liquid medium and 64.7% for the samples stored on the FTA card, with high detection accuracy in the DNA samples recovered from the FTA card (area under the curve = 0.958; 95% confidence interval = 0.890–1.000). The concordance between the results obtained using the 2 storage media was 94.1% (Kappa = 0.866). These preliminary results suggest that collection of cervical material on an FTA card may be an alternative to storage in liquid medium since the liquid medium has some limitations. In addition, DNA recovery from the card using ethanol-based liquid medium streamlines the workflow in the laboratory and reduces the cost associated with reagents, thereby facilitating access to the HPV test in places with few resources and potentially improving cervical cancer screening.

Dry storage casks filled with nuclear spent fuel assemblies are closed by bolted lids. The continuity of knowledge of the nuclear material inside the cask, once verified by Safeguards inspectors must be maintained. The work presents an ultrasonic investigation system able to recognize any attempt to tamper with the thread that could allow the seal to be removed without unscrewing it, meaning opening of the lid without leaving trace of it. For this purpose, we have defined a modification consisting of an inclusion of a thread within a larger thread (M45 instead of a M36). The proposed method is based on the analysis of the characteristic velocity and diameter estimation for distinguishing a different thread respect to the M36 in presence of large variation of the Castor V ductile material used for the storage casks.

Nowadays, nuclear power plants can use a dry storage cask (DSC) for the spent nuclear fuel (NSF) on site. It is a reinforced concrete vessel, which has an internal stainless steel cylinder. Its main function is to provide a barrier against radiation, to cool down the spent fuel and to avoid nuclear fission through the internal metallic surface that contains the radioactive material. This vessel has been designed to withstand different conditions such as free fall, penetration, crushing and extreme temperatures. However, there is limited knowledge about the assessment of an aircraft impact on such vessels in the open literature. In this paper, the case of an oblique impact (45° impact angle with respect to the horizontal) of a light aircraft against a dry storage cask was considered. Its structural integrity was evaluated. The containers were considered to be located in an outdoor area. The evaluation was carried out with the commercial ANSYS® code.

Current practice for commercial spent nuclear fuel management in the United States of America (US) includes storage of spent fuel in both pools and dry storage cask systems at nuclear power plants. Most storage pools are filled to their operational capacity, and management of the approximately 2,200 metric tons of spent fuel newly discharged each year requires transferring older and cooler fuel from pools into dry storage. In the absence of a repository that can accept spent fuel for permanent disposal, projections indicate that the US will have approximately 134,000 metric tons of spent fuel in dry storage by mid-century when the last plants in the current reactor fleet are decommissioned. Current designs for storage systems rely on large dual-purpose (storage and transportation) canisters that are not optimized for disposal. Various options exist in the US for improving integration of management practices across the entire back end of the nuclear fuel cycle.

Precise treatment of a disease, with a concerted analysis at the genomic and phenotypic level, is a paradigm shift from the one-size-fits-all treatment practiced for centuries. As part of the Precision Medicine Initiative, a million cohort samples will be collected for research and development of unique genetic markers in the study of the relationship of genomic markers to cancer. The million cohort samples are only as good as the conditions under which the samples are collected and stored. The purpose of this review is to discuss an economically viable biobanking solution for tissue, blood, and nucleic acid storage for such an endeavor! Tissue biopsy and whole blood are two common types of tissues collected for the Precision Medicine Initiative. Tissue samples can be stored as formalin-fixed paraffin-embedded (FFPE) blocks at ambient for decades, but fresh tissue samples although limited in sample size are better suited for downstream application. Postmortem collection of tissue is a good alternative to fresh tissue samples if the samples can be acquired in a timely manner before cold ischemia sets in. Blood is the preferred tissue sample for the Precision Medicine Initiative as it is easy to collect compared to other tissue types. Energy and space limitations are going to be crucial for storing a million samples for decades. Dry storage at ambient temperature is an alternative to the ultra-low-temperature storage of samples. Dry storage of whole blood samples as dried blood spots (DBS) or of the isolated components such as nucleic acids at ambient is ideal. In this review, we discuss the ambient temperature storage of blood samples and of nucleic acid. The million cohort biobanked blood and tissue samples will be crucial references for decades to come as new discoveries are made and new markers identified. Collection of blood samples at ambient as DBS and storage of the associated nucleic acid at ambient will be the key to the long-term success of biobanking of this large cohort.

Spent fuel production is one of the main problems of nuclear power plants that should be managed properly considering the strategy of each country. Today, in most of nuclear power owner countries, the interim storage has been selected as the temporary solution of spent fuel management because of absence of deep geological repositories and no tendency for reprocessing. On the other side, considering the merits of storage in dual purpose casks based on dry storage, this method was chosen for interim storage. By taking into account that the only operating reactor of Iran is of Water-Water Energetic Reactor (WWER)-1000 type, proposed TK-13 cask by Russia which is the manufacturer of these types of reactors has been considered. In this study, the calculation of basket holding spent fuel assembly criticality of this cask has been analyzed for two modes of fresh and spent fuel by ORIGEN2.1 and MCNPX2.6 nuclear codes. The criterion of the nuclear criticality safety for effective multiplication factor (keff) should be 0.95 and 0.98 for many ordinary and accident conditions, respectively. Therefore, the results show that a cylindrical basket with 66 cm diameter and 28 cm pitch with internal holding basket made of borated steel with 0.1% borate and steel free from borate would meet the criticality of cask, respectively.

The performance of vertical concrete casks (VCC) for storage of spent nuclear fuel (SNF) under hypothetical accident conditions is of particular importance given the planned extensions of service-lives of such structures in the absence of a permanent disposal solution. Numerical models are created in this paper to simulate the structural response of a generic VCC in the cases of end-drop (handling drop) and tip-over considering material degradation. A concrete damage plasticity model (CDP) was calibrated using standard material tests to capture the non-linear behavior of concrete. Similarly, the steel properties and the properties of the soil supporting the cask foundation were based on material test data. The finite element models (FEM) were validated using experimental data from end-drop and tip-over tests of a 1/3-scale VCC performed by the same authors and reported elsewhere. The numerical results are compared with the experimental measurements in terms of velocity, acceleration, damage, and failure modes to gain confidence in the numerical results. Thereafter, a push-over analysis method was proposed and performed on the VCC for the first time to investigate the effect of different levels of material degradation on the structural response of VCC. The reduction in the concrete reinforcing steel area and bond degradation due to corrosion, and concrete strength reduction due to effects such as alkali-silica reactivity were considered as the variables for the parametric analysis. The results are interpreted to understand the changes in the performance of VCC in the long-term when subjected to hypothetical accident conditions in comparison to intact as built conditions.

The role of dry storage in spent nuclear fuel management becomes more and more important. Originally intended to serve as a temporary solution for a few decades until final disposal, now dry storage period is to be extended to 100 years and beyond. It has to be proven for licensing that the fuel rod integrity during dry storage is ensured. Since it is difficult to provide experimental support, the licensing process has to rely largely on numerical simulations. This paper reviews the literature associated with the modeling of spent nuclear fuel under dry storage conditions. The main phenomena threatening the fuel rod integrity and the numerical models representing them are described here. Moreover, the most recent or currently ongoing experimental efforts that could support the modeling of nuclear fuel in dry storage in the future are discussed. Finally, this paper reviews approaches to dry storage modeling chosen by different countries. In general, these approaches are similar and can be described as a calculation chain consisting of neutronics–thermo-hydraulics–fuel performance computations where sensitivity and uncertainty studies are crucial elements.

Dry interim storage of spent fuel has expanded significantly; as any other option it should ensure fuel rod integrity under any circumstance. This requires cooling fuel assemblies. Because major degrading mechanisms of cladding are influenced by temperature, the threshold conditions selected in most regulatory requirements is based on Peak Cladding Temperature (PCT). This paper proposes a calculation route of PCT free of the high complexity of fluid-dynamics and the long computing time burden. Based on heat transfer equations applied over conceptually suitable systems, a thermal resistance scheme is set and solved, resulting in fast and accurate estimates. Both features would enable this methodology to be coupled with fuel performance codes without overloading each single thermo-mechanical calculation. The performance of the method is illustrated through its application to a concrete and a metallic cask, both under steady and transient conditions. When compared to results from 3D-CFD calculations, the deviations observed in the PCT estimates are lower than 5%, and the time calculation saving has been estimated to be about 105 times faster. This method is planned to be extended to other variables like the minimum temperature in the cask, of utmost importance to estimate the ductile-to-brittle transition of cladding materials.

Computational fluid dynamics (CFD) was used in this study to numerically simulate the heat removal and hybrid ventilation characteristics of a vertical dry storage cask for spent nuclear fuel. The parameters included a Grashof number of 1.0x1011, an approaching wind incidence angle of 0° or 45°, and a Reynolds number (Re) of 2.7 × 10 4 - 8.0 × 10 5 ( Gr / Re 2 = 0.15 - 1 37 ). As shown by the results, the buoyant airflow dominated the heat removal capability of the cask at low Re ( 2.7 × 10 4 ). When the Re was increased to 5.3 × 10 4 - 1.3 × 10 5 , the wind-induced channel airflow compromised the buoyant airflow, thus reducing the heat removal capacity of the cask. When the Re was ⩾ 2.7 × 10 5 , the wind-induced airflow dominated.

Large clay jars have long been popular for both wet and dry storage, but are particularly associated with Mediterranean wines and olive oil. Such ‘pithoi’ also underpin important historical shifts in social complexity and landscape investment, play prominent roles in Mediterranean social life, and thus offer an excellent opportunity to think about the deeper consequences of container culture.

Biorepositories are “libraries” in which biospecimens, bacteria, or DNA and RNA extracts are stored for either clinical or research purposes. Such specimens enable modern molecular-based research and could support method verification, validation, quality control, and, in some cases, proficiency testing in clinical laboratories. Cryopreservation of extracted nucleic acids ensures the stability and longevity of DNA and RNA from patient samples, with the most common methods used for long-term storage of samples being the use of −80°C freezers or liquid nitrogen. Frozen biospecimens are crucial for translational research as they contain well-preserved nucleic acids and protein; however, traditional −80°C freezers consume both energy and space, with costs of maintenance and repairs reaching thousands of dollars annually to freeze and protect biospecimens. Additionally, liquid nitrogen is hazardous to work with, and failure to maintain adequate levels in storage containers can result in loss of specimens. Recently, new room temperature, or “green,” technology has been developed for dry storage of nucleic acids, ultimately reducing costs in terms of energy output and carbon footprint. This review compares and contrasts the use of dry-storage infrastructure with that of freezing samples, in terms of its use in clinical microbiology and highlights considerations to be made if implementing the technologies. Storage alternatives to freezers that equal or exceed their performance with regard to sample preservation and protection against degradation while at the same time reducing space requirements, costs, and energy consumption could be a financial and operational benefit if properly deployed and characterized. Perhaps it is time for laboratories to consider getting molecular quality control material and remnant extracted samples in from the cold and to evaluate the use of dry, room temperature storage technology for use in our microbial biorepositories.

Safer, more convenient methods for cervical sample collection and storage are necessary to facilitate human papillomavirus (HPV) DNA testing in low-resource settings. Our study aimed to evaluate the stability of cervical specimens collected with dry swabs and stored dry, compared to liquid-based cytology (LBC) samples, as detected by HPV DNA testing. Women with abnormal cytological findings or HPV-positive results at colposcopy were recruited from the West China Second University Hospital, Sichuan University, between October 2013 and March 2014. From each woman, physicians collected cervical specimens with a swab placed into a Sarstedt tube and a CytoBrush placed into LBC medium. Samples were randomly assigned to be stored at uncontrolled ambient temperature for 2, 7, 14, or 28 days and then were tested for 14 high-risk HPV (HR-HPV) types using the cobas HPV test. The rates of agreement between dry swab and LBC samples for any HR-HPV type, HPV16, HPV18, and the 12 pooled HR-HPV types were 93.8%, 97.8%, 99.4%, and 93.2%, respectively, with kappa values of 0.87 (95% confidence interval [CI], 0.83 to 0.91), 0.94 (95% CI, 0.91 to 0.97), 0.94 (95% CI, 0.87 to 1.00), and 0.86 (95% CI, 0.82 to 0.90). The performance of swab samples for detection of cervical precancerous lesions by means of cobas HPV testing was equal to that of LBC samples, even with stratification by storage time. Dry storage of swab-collected cervical samples can last for 1 month without loss of test performance by cobas HPV testing, compared to LBC samples, which may offer a simple inexpensive approach for cervical cancer screening in low-resource settings.

Statement of problem Overnight removal of complete dentures is recommended to reduce the incidence of denture stomatitis. The effect of overnight storage conditions is unclear. Purpose The purpose of this systematic review was to assess the effect of overnight storage conditions on complete denture colonization by Candida albicans and to explore the effect of overnight storage conditions on the dimensional stability of complete dentures. Material and methods Two electronic databases were searched through to November 2018. The terms “denture*”, “dental prosthes*”, “acrylic resin*”, “storage”, “nighttime”, “overnight”, “wet”, “dry”, “water*”, and “solution” were chosen. Articles meeting the inclusion criteria were selected. For both research questions, studies that did not store the dentures overnight or for a minimum of 8 hours were excluded. For the primary research question, studies that were not randomized controlled studies or comparative studies were excluded. Results The database search strategy resulted in a total of 159 potential studies. After screening titles and abstracts and applying the inclusion and exclusion criteria, 6 studies were retrieved for a full-text assessment. Hand searching was also performed. Four studies were included in the systematic review for the primary research question. Three studies were included for the secondary research question. A meta-analysis could not be performed because of variation in study design. Conclusions Cleaning of dentures before overnight storage helps reduce C. albicans colonization. If the dentures are not cleaned, the use of an alkaline peroxide–based cleaning tablet should be considered. Alternately, overnight dry storage is an option for reducing C. albicans colonization, with clinically insignificant changes to the dimensions of the complete denture. Storing dentures in water alone may promote C. albicans colonization.

Welded stainless steel canisters are used in dry storage systems of spent nuclear fuel from commercial power reactors in the U.S. These systems were initially licensed for 20 years and may receive license renewals for 40 more years from the U.S. Nuclear Regulatory Commission (NRC). The requirements for license renewal include aging management programs (AMPs) to ensure systems, structures, and components (SSCs) continue to perform their safety function. Nondestructive examination (NDE) plays an important role in AMPs that rely on inspection to detect service degradations such as chloride-induced stress corrosion cracking (CISCC) of austenitic stainless steel canisters so that mitigation actions can be taken to manage the aging effects. The American Society of Mechanical Engineer (ASME) is currently developing a code case for the in-service inspection (ISI) of dry storage canisters. The nuclear industry is also developing inspection systems for conducting examinations of canisters. This paper is intended to...

Irradiated or Spent Nuclear Fuel (SNF, where it could be “used nuclear fuel” if reprocessing facilities are available) is periodically removed from nuclear power reactors and allowed to decay in suitable storage facilities. This paper attempts to calculate the relationships between sizes and costs of wet/dry and onsite/offsite SNF storage. The methodology is (1) to propose cost models based on publicly available data and (2) to estimate cost equations to compare the various storage costs. When the fuel pool nears capacity, the cheapest alternative is to transfer SNF to onsite dry storage. Once a nuclear power plant has been decommissioned, and only the onsite dry storage facility remains, there appears to be little economic reason (from the nuclear power plant owner/operator’s viewpoint) to move the SNF to consolidated facilities because of extra monetary and non-monetary costs. Unless there are explicit national policies and funded programs to manage SNF, there are likely to be legacy sites with stranded SNF. On the other hand, there is a consensus that consolidated facilities (1) would be more safe and secure than dispersed onsite storage locations, (2) would facilitate final disposal, and (3) might reduce the risks perceived by local communities of storing SNF.

Evaluations of the impact resistance of a dry storage cask under mechanical impact loadings resulting from a large commercial aircraft crash have become an important issue for designers and evaluators, in order to promote interim dry storage activities and to evaluate design safety margins. This study presents a method to evaluate the structural integrity of a generic metal cask subjected to various mechanical loading conditions, which represent aircraft engine impacts, on different locations of the cask body. Thirty representative impact conditions are analyzed to provide a comprehensive evaluation of cask damage response. The applied engine impact load–time functions were carefully re-derived by utilizing CRIEPI’s proposed curve through Riera’s approach for six impact velocities, and applied to five locations on a freestanding cask: lateral impacts on the lower half, center of gravity, and upper half of the cask body, corner impact on the lid closure, and vertical impact on the center of the lid closure. A nonlinear dynamic finite element analysis is performed to evaluate the dynamic response of the cask lid closure system and to calculate the lid gaps. The release fractions from the cask to the environment for each impact condition are preliminarily estimated by referring to a proposed methodology from literature. It is believed that this paper presents a systematic process to connect the mechanical analysis of a cask response at the moment of aircraft engine impact with its radiological consequence analysis.

Since the Dry Storage System (DSS) has passed into a widespread middle-term storage method for Spent Nuclear Fuels (SNFs), the situation monitoring technology for a DSS should be further improved to ensure the reliability of DSS during storing time. However, a passive cooling mechanism with a full-sealed storage requirement causes that the internal situation cannot be directly monitored by thermocouples inserted into the DSS. In this study, a new surveillance method, therefore, has been proposed to overcome this problem. It can predict the DSS situation through measuring the temperature profile at the Transportable Storage Canister (TSC). A validated CFD methodology has been utilized to confirm the method through simulating the thermal characteristics of the ChinShan DSS (CSDSS). The major factors, such as the thermal loading, accident situation and flaw caused by penetrated hole probably, have been considered in this present work. The result shows that the above-mentioned issues would obviously affect the temperature profile on the TSC and can be identified via detecting the temperature profile difference on of TSC. These results confirm that the indirectly surveillance method has enough capability to replace the original monitored method and provide more system information of DSS vendor for middle-term storage.

In recent years, the final disposal facility for the long-term storage of high radioactive waste is an important issue and an urgent task for nuclear Industry. This study is focus on the understanding the procedure of dry storage system in a nuclear power plant. The dry storage system is known as transportable storage canister (TSC) packing by using spent fuel placed in vertical concrete cask (VCC) or VCC with add-on-shell (AOS) canister and then those conveyed VCC or AOS will be put on the concrete pad. A numerical simulation for evaluation the behavior of VCC and AOC under the earthquake hits is used the finite element model by LS-DYNA and the real seismic behavior is obtained using shaking table test. Test results indicate that the simulation by numerical model can slightly simulate the dynamic records by shaking table test. This is because that the behavior of shaking table test is the rocking motion but the numerical model is the sliding motion. The surface roughness between the cask and concrete pad is an important variable and it needs more numerical simulation to solve the interface and friction coefficient between the cask and concrete pad.

Objective: To compare the incidence of microleakage associated with contemporary esthetic restorative-adhesive systems following cyclic wet and dry storage as a representation to the dry mouth condition. Methods: Standardized cervical cavities in both buccal and lingual surfaces of 100 extracted human premolars were restored in 10 groups (n=10 with 20 cavities) using 7 contemporary esthetic restoratives and 3 adhesive systems following their manufacturers’ instructions. Cavities in groups 1–3 were restored with self-adhesive restoratives; conventional glass-ionomer (GI) (Ketac Molar Aplicap), resin modified glass-ionomer (RMGI) (Vitremer) and self-adhesive flowable composite (SAFC) (Fusio Liquid Dentin). Conventional flowable (FC) (Filtek Z350 Flow), nano-hybrid (HC) (Filtek Z250 XT) and nano-filled (NC) (Filtek Z350 XT) methacrylate-based composites were used in conjunction with total-etch, 2-step adhesive (Adper Single Bond 2) to restore cavities in groups 4–6. The same restoratives were also used to restore cavities in groups 8–10 in the presence of self-etch, 1-step adhesive (Adper Easy One), while cavities in group 7 were restored with silorane-based composite (Filtek P90) together with its specific adhesive system. Five restored teeth from each group (10 cavities) were subjected to cyclic storage in wet and dry environment, each for 12h/day and for a total period of 30days, while the other 5 were tested with no cyclic storage to serve as control. Using dye penetration technique, the associated microleakage was then scored from 0 to 4 for all restorations according to the depth of dye penetration at both occlusal and gingival interfaces. The incidences of each score were recorded in percentages and the numerical microleakage data were statistically analyzed using Kruskal–Wallis and Mann–Whitney comparisons at α=0.05 to stand on the significance of differences detected between groups. Results: All restorative systems showed incidences of microleakage before and following cyclic storage in wet and dry environment with no specific manner declared for any. Statistical analysis of the scored data revealed no difference between different restorative systems under no storage condition, however HC, S and FC in groups 5, 7 and 8 showed higher rates of microleakage when subjected to cyclic wet-dry storage (Mann–Whitney, P0.05). For each restorative system, no significant difference (Kruskal–Wallis, P>0.05) was recorded between microleakage values recorded at occlusal and gingival interfaces. Conclusion: Occlusal and gingival sealing ability of flowable resin composite bonded with self-etch, 1-step adhesive is the most affected following cyclic wet-dry storage. Selection of such restorative option accordingly is not suggested for patients suffering from dry mouth.

© 2020 The Author(s) Currently, Indonesia has only three nuclear research reactors. However, Indonesia is the world's fourth most populous country. Owing to the enormous size and rapid growth of the population and the limited availability of fossil fuel and renewable energy resources, the construction of new nuclear power plants (NPPs) has been considered. Because of this, the management policies for long-term spent nuclear fuel in Indonesia have become crucial. This paper reviews the current handling and future management strategies for spent nuclear fuel in Indonesia. With a maximum capacity of 1448 spent fuel elements, Indonesia's interim wet storage of spent fuel (ISSF) is designed to store spent nuclear fuel arising from 25 years of reactor operation at maximum power. However, with the existing low-power reactor operation, the ISSF could be utilized for more than 75 years. The potential problem for long-term storage in the ISSF is system, structure, and component (SSC) aging. Continuous planning, operation, monitoring, and maintenance of the SSC in the ISSF have been conducted to ensure safe long-term utilization of the facility. In accordance with the possibility of NPP construction in the future, three possible scenarios may be considered for future nuclear spent fuel management strategies in Indonesia: 1) wet storage - dry storage - disposal; 2) wet storage -repatriation or sending to other countries; and 3) wet storage - moving to wet- or dry storage of NPP candidate - disposal.

As the storage terms of spent nuclear fuel (SNF) are extended, monitoring of safety related parameters becomes more important for safe operation of the dry storage casks. The cask integrity assurance will be greatly enhanced if the canister pressure and the peak cladding temperature (PCT) can be reliably inferred from canister surface temperatures (CSTs), and this would also eliminate need for any measurement sensor that penetrates the canister pressure boundary. In the present work, a method to reliably predict the pressure and the PCT using artificial neural network (ANN) models has been developed using CSTs measured at axially spaced positions. To validate the method, a test rig with a single fuel assembly was constructed, and pressure variation tests were carried out. ANN models were developed using the experimental data and the models were augmented by the functional link with CST profile shape information for improved prediction performance. A computational fluid dynamics (CFD) code was then used to simulate these pressure variation tests, and comparison was made to assess the discrepancies between the simulation and the measurement results. The ANN models were trained on the databases built from the CFD calculation results. The measured CST signals were converted to the CSTs of simulation hyperspace on which the ANN models were trained. The conversion was done with the compensation factors obtained at a known reference state. The ANN monitoring models showed good prediction performances in spite of the discrepancies between the measurement and the simulation results.

We investigated the suitability of thermography for detecting a potential relocation of the inventory of dry storage containers of type CASTOR V/19. We used numerical simulations of the heat transfer in the container to determine the sensitivity of the wall temperature distribution to such changes. We conducted an analysis for three different hypothetical damage cases: a 9 cm compaction of the fuel in all fuel rods of a single fuel assembly, the same compaction in all fuel assemblies and a compaction of all fuel assemblies by 50 %. The analysis shows that the temperature difference between intact case and all three damage cases after 40 years is too low for an accurate detection becoming even lower for longer storage periods. Temporal thermal insulation of the containers may increase the temperature gradients but reducing the spatial resolution.

Biobanking is a rapidly growing industry, covering diverse fields such as human medicine, farm animal production, laboratory animals record keeping, and wildlife conservation. Presently, biobanking is done almost exclusively by cryopreservation, followed by maintenance of the samples under liquid nitrogen. Cryopreservation has satisfactory efficiency but it comes with a host of problems, and the process is highly species-specific. Like in many other walks of life, we turn to Nature in search for better alternatives. Nature opted for controlled drying rather than water preservation via freezing when long-term preservation is desired, a strategy known as 'anhydrobiosis'. To achieve reversible drying, anhydrobiotic organisms utilise an assortment of protective materials, including disaccharides, late embryogenesis abundant proteins, anhydrin, heat shock protein, and more. Once dry, desiccation-tolerant organisms can survive extended periods of time and be resistant to extreme environmental stressors. Over the past 70 years researchers attempted applying this idea to preserve desiccation-sensitive mammalian cells in the dry form. At present dried cells mostly do not resume biological activity upon rehydration. The DNA, however, is often well preserved to allow utilisation in advanced reproductive techniques. Spermatozoa are by far the most commonly dried cell type, primarily from mice and bulls. A number of drying approaches have been applied, with freeze-drying taking the lead. To date offspring have been produced from dried spermatozoa in mouse, rat, hamster, rabbit, and horse. No offspring were produced from dried somatic cells. Desiccation experiences a sharp increase in interest and research output in recent years. Presented here is an overview of dry preservation, its possible applications, the open questions the field is still facing, and some suggested directions for the future.

In this paper, a calculation chain for the analysis of spent nuclear fuel in long-term interim dry storage is demonstrated. The calculation chain consists of reactor physics burnup simulation for obtaining the decay heat, Computational Fluid Dynamics (CFD) simulation for the temperatures of fuel rods and the dry storage cask, and finally, cladding integrity analysis. Each succeeding calculation step uses the results from the previous step as boundary conditions. The applied codes are Serpent Monte Carlo reactor physics burnup code, open-source OpenFOAM CFD code, and VTT-ENIGMA fuel performance code. The peak cladding temperatures are calculated with OpenFOAM at different instants of time, ranging from 3.4 to 300 years after unloading from the reactor. The chosen demonstration case considers 17 × 17 PWR fuel stored in a CASTOR® V/21 type dry storage cask. The main parameters of interest in the last stage of the analysis are the cladding creep hoop strain and stress during dry storage. The developed analysis methodology helps to ensure the safety of long-term dry storage.

This study provides an independent, outside-in estimate of the cost and schedule risks of nuclear waste storage projects. Based on a reference class of 216 past, comparable projects, risk of cost overrun was found to be 202% or less, with 80% certainty, i.e., 20% risk of an overrun above 202%. Based on a reference class of 200 past, comparable projects, risk of schedule overrun was found to be 104% or less, with 80% certainty, i.e., 20% risk of overrun above 104%. Cost risk and schedule risk are both substantial for nuclear waste storage projects., arXiv admin note: substantial text overlap with arXiv:1901.03698

Objective To use the Health Food Pantry Assessment Tool (HFPAT) to identify policy, systems, and environmental (PSE) changes in Arizona's food pantries. Use of Theory or Research The HFPAT was selected as an observational survey that measured the healthfulness of food pantry environments and provided PSE resources to guide food pantries and the University of Arizona Supplemental Nutrition Education - Program (UA SNAP-Ed) programming. Target Audience Four food pantries (Apache-2, Maricopa-2 Counties) that participated in SNAP-Ed completed the HFPAT. Program Description The SNAP-Ed sent the HFPAT in advance of site visits. Two Arizona SNAP-Ed staff independently completed the observational portions of the survey and results were compared. The survey was completed by interviewing the food pantry staff. Reports were generated using Qualtrics® and given to the food pantries. The HFPAT Resource Guide, which provides a resource for each section, was included. Evaluation Methods The HFPAT contained 69 questions divided into five sections: pantry location and entrance, food available to clients, policies of the food pantry, frozen chilled, dry storage and food safety, and services for clients. It provided a numeric score on a scale of 0-100; with a score of 100 signifying the healthiest food pantry environment. Results Four food pantries were assessed. The total scores ranged from 41 to 50 (mean: 46.25 out of 100). The food pantries’ mean scores for each section were: a) 9.25 out of 15 possible points; b) 19.25 out of 57 possible points; c) 6 out of 12 possible points; d) 6.25 out of 10 possible points; and e) 4.5 out of 6 possible points. Conclusions The UA SNAP-Ed used the HFPAT to assist food pantries in identifying potential PSE interventions. This evaluation tool provided direction to the UA SNAP-Ed to give specified technical assistance to the food pantries, and resources to improve their low-scoring areas. Funding None.

Geological disposal (GD) of radioactive waste is close to becoming a reality for Finland, Sweden and France. High-technology development and advanced knowledge has made it possible to defend the feasibility and the safety of such facilities, making the European Union a leader in the field. Other European countries are closely behind, developing high competence through advanced research programmes, research infrastructures and public engagement.At the other extreme, there are countries whose GD programmes are at an early stage and no systematic research programmes exist. These include several new Member States but not the Czech Republic and Hungary, both of which have already initiated a siting process.There are several common reasons for this delay in schedule: small and relatively younger nuclear energy programmes, return of the spent fuel (especially from research reactors) to the countries of origin, open fuel cycle concept (requiring at least 50 years of wet and dry storage). In this context, there has been little pressure on setting up an early GD programme. Currently their disposal concepts are only generic and in most of these countries need updating, taking into account the current socio-economic context.However, some of these new Member States still aim to have a GD in operation within several decades, e.g. 2055 in Romania and 2067 in Slovenia. Strategic planning based on the experience of more advanced programmes shows the GD process should start immediately in order to be able to achieve these deadlines.In this context, the implementation of the EC Directive 70/2011 gives the opportunity to progress the advancement of the GD process in these countries.

The paper is devoted to the description of project of storage system for the spent nuclear fuel. The proposed dry storage system is based on the natural convection of air so no additional fans are needed for the cooling. In the paper basic parameters of the storage as well as some preliminary computations verifying its concept are described.

The setup programme of dry storage of using spent fuel is that transportable storage canister (TSC) packing by using spent fuel placed in vertical concrete cask (VCC), then conveyed VCC from plant to site and put concrete pad. After VCC is in position, place the add-on-shell (AOS).This research analyses and simulate the behavior of VCC and AOC during earthquake by LS-DYNA which is dynamic transient structural analysis of finite element method. The main issue is the shaking response of VCC under earthquake while there is a hump on the bottom floor. From the result, the perturbation of dynamic stability of VCC and AOS have been occurred when the hump existed onto the floor. The construction specification of VCC/AOC bottom flatness should be considered

Cost analysis of dry storage of spent nuclear fuel (SNF) discharged from Barakah nuclear power plants in the UAE was performed using three variables: average fuel discharge rate (FD), discount rate (d), and cooling time in a spent fuel pool (Tcool). The costs of dry storage as an interim spent fuel storage option in the UAE were estimated and compared between the following two scenarios: Scenario 1 is ‘accelerated transfer of spent fuel to dry storage’ that SNF will be transferred to dry storage facilities as soon as spent fuel has been sufficiently cooled down in a pool for the dry storage; Scenario 2 is defined as ‘maximum use of spent fuel pool’ that SNF will be stored in a pool as long as possible till the amount of stored SNF in the pool reaches the capacity of the pools and, then, to be moved to dry storage. A sensitivity analysis on the costs was performed and multiple regression analysis was applied to the resulting net present values (NPVs) for Scenarios 1 and 2 and ΔNPV that is difference in the net present values between the two scenarios. The results showed that NPVs and ΔNPV could be approximately expressed by single equations with the three variables. Among the three variables, the discount rate had the largest effect on the NPVs of the dry storage costs. However, ΔNPV was turned out to be equally sensitive to the discount rate and cooling period. Over the ranges of the variables, the additional cost for accelerated fuel transfer (Scenario 1) ranged from 86.4 to 212.9 million $. Calculated using the maximum difference (212.9 M$) between the two scenarios, the accelerated fuel transfer to dry storage could incur the additional electricity rate 8.0 × 10−5 USD/kWh, which is not considered to be significant, compared to the overall electricity generation cost.

Wheat flour samples from three agricultural systems and two storage modes were evaluated and compared in dynamics of their titratable acidity and Falling number by Hagberg-Perten method during one year storage and their interaction. The obtained results indicate strong relationships between increasing acidity and lowering α-amylase activity using samples after biological, ecological agriculture systems and dry storage mode (without temperature control). On the other hand, intensive agriculture and cool storing (T +6±2ºS) provided independent change in those indices and better technological properties for the end of the storage period.

A new type of dry storage system is designed by Shanghai Nuclear Engineering Research & Design Institute (SNERDI), which can efficiently remove the decay heat of the hexagonal spent fuel assemblies such as VVER fuel assemblies. The dry storage system includes a Ventilated Concrete Cask (VCC) and a Multi-assembly sealed basket (MSB). Decay heat is removed by natural circulation with helium and air, heat conduction and thermal radiation heat transfer. Thermal performance of the dry storage system has been investigated by two different numerically methods, i.e., the Computational Fluid Dynamics (CFD) method and the lumped parameter method. The CFD method is utilized based on the commercial software STAR-CCM+, and fuel assemblies are modeled as a porous medium characterized by effective conductivity and the permeability and inertial resistance factor, while other geometry including the lids, base plates, inner and outer shell are modeled explicitly with necessary simplifications. The lumped parameter method is utilized based on the system code GOTHIC, the geometry and the fuel assemblies are divided and represented by 44 volumes. The flow of the air and helium are modeled by flow path which connects the related volumes, and the heat transfer between fluid and solid structures are modeled by thermal conductor models. Heat transfer by convection, conduction and thermal radiation is modeled in both of the two methods. The maximum temperature of spent fuel assembly can be obtained by both of the two methods, which can be a design basis for investigations attempting to improve the performance of the dry storage system. It is found that the simulation results calculated by the lumped parameter method are more conservative than those calculated by the CFD method. Both methods indicate that after the storage of 7.5 years, the dry storage system is able to remove the decay heat from the hexagonal spent fuel assemblies, keeping maximum cladding temperature below the design limit. Besides, detailed flow characteristic are obtained by CFD simulation. Furthermore, effects of MSB normal operating pressure and the ambient temperature are studied.

The generation of high volumes of coal combustion products (CCPs), in conjunction with federal initiatives to regulate waste management practices, has led to in-depth examinations of the potential risks associated with CCP management and a review of documented damage cases in the United States. There are two main types of CCP management: wet storage of CCP in surface impoundments and dry storage in landfills. Both the risk assessments and the damage cases show that under certain hydrogeological environments, wet storage of CCP has the potential to be associated with human and ecological risk to groundwater and surface water; managing the risks of fugitive dust is also an important issue for landfill disposal. A variety of best practices and corrective actions can help manage these risks. Overall, due to regulatory requirements in the United States, there is trend toward landfills as the primary type of CCP management facility; regulations are also causing many surface impoundments to close. When closing an impoundment, in addition to evaluating the long-term potential impacts of the closure activities to groundwater and surface water quality, the short-terms risks associated with each closure option must be also be considered.