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Title: Regulatory Perspective on Potential Fuel Reconfiguration and Its Implication to High Burnup Spent Fuel Storage and Transportation - 13042

Abstract

The recent experiments conducted by Argonne National Laboratory on high burnup fuel cladding material property show that the ductile to brittle transition temperature of high burnup fuel cladding is dependent on: (1) cladding material, (2) irradiation conditions, and (3) drying-storage histories (stress at maximum temperature) [1]. The experiment results also show that the ductile to brittle temperature increases as the fuel burnup increases. These results indicate that the current knowledge in cladding material property is insufficient to determine the structural performance of the cladding of high burnup fuel after it has been stored in a dry cask storage system for some time. The uncertainties in material property and the elevated ductile to brittle transition temperature impose a challenge to the storage cask and transportation packaging designs because the cask designs may not be able to rely on the structural integrity of the fuel assembly for control of fissile material, radiation source, and decay heat source distributions. The fuel may reconfigure during further storage and/or the subsequent transportation conditions. In addition, the fraction of radioactive materials available for release from spent fuel under normal condition of storage and transport may also change. The spent fuel storage and/or transportation packaging vendors, spentmore » fuel shippers, and the regulator may need to consider this possible fuel reconfiguration and its impact on the packages' ability to meet the safety requirements of Part 72 and Part 71 of Title 10 of the Code of Federal Regulations. The United States Nuclear Regulatory Commission (NRC) is working with the scientists at Oak Ridge National Laboratory (ORNL) to assess the impact of fuel reconfiguration on the safety of the dry storage systems and transportation packages. The NRC Division of Spent Fuel Storage and Transportation has formed a task force to work on the safety and regulatory concerns in relevance to high burnup fuel storage and transportation. This paper discusses the staff's preliminary considerations on the safety implication of fuel reconfiguration with respect to nuclear safety (subcriticality control), radiation shielding, containment, the performance of the thermal functions of the packages, and the retrievability of the contents from regulatory perspective. (authors)« less

Authors:
; ; ; ;  [1];  [2]
  1. U.S. Nuclear Regulatory Commission - NRC, Washington, DC 20555-0001 (United States)
  2. Oak Ridge National Laboratory (United States)
Publication Date:
Research Org.:
WM Symposia, 1628 E. Southern Avenue, Suite 9-332, Tempe, AZ 85282 (United States)
OSTI Identifier:
22224844
Report Number(s):
INIS-US-13-WM-13042
TRN: US14V0278045799
Resource Type:
Conference
Resource Relation:
Conference: WM2013: Waste Management Conference: International collaboration and continuous improvement, Phoenix, AZ (United States), 24-28 Feb 2013; Other Information: Country of input: France; 11 refs.
Country of Publication:
United States
Language:
English
Subject:
12 MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; 42 ENGINEERING; AFTER-HEAT; ANL; BURNUP; CASKS; CLADDING; CONTAINMENT; CONTROL; CRITICALITY; DRY STORAGE; DUCTILE-BRITTLE TRANSITIONS; FISSILE MATERIALS; FUEL ASSEMBLIES; ORNL; RADIATION PROTECTION; RADIATION SOURCES; RADIOACTIVE MATERIALS; SAFETY; SPENT FUEL STORAGE; SPENT FUELS

Citation Formats

Li, Zhian, Rahimi, Meraj, Tang, David, Aissa, Mourad, Flaganan, Michelle, and Wagner, John C. Regulatory Perspective on Potential Fuel Reconfiguration and Its Implication to High Burnup Spent Fuel Storage and Transportation - 13042. United States: N. p., 2013. Web.
Li, Zhian, Rahimi, Meraj, Tang, David, Aissa, Mourad, Flaganan, Michelle, & Wagner, John C. Regulatory Perspective on Potential Fuel Reconfiguration and Its Implication to High Burnup Spent Fuel Storage and Transportation - 13042. United States.
Li, Zhian, Rahimi, Meraj, Tang, David, Aissa, Mourad, Flaganan, Michelle, and Wagner, John C. 2013. "Regulatory Perspective on Potential Fuel Reconfiguration and Its Implication to High Burnup Spent Fuel Storage and Transportation - 13042". United States. doi:.
@article{osti_22224844,
title = {Regulatory Perspective on Potential Fuel Reconfiguration and Its Implication to High Burnup Spent Fuel Storage and Transportation - 13042},
author = {Li, Zhian and Rahimi, Meraj and Tang, David and Aissa, Mourad and Flaganan, Michelle and Wagner, John C.},
abstractNote = {The recent experiments conducted by Argonne National Laboratory on high burnup fuel cladding material property show that the ductile to brittle transition temperature of high burnup fuel cladding is dependent on: (1) cladding material, (2) irradiation conditions, and (3) drying-storage histories (stress at maximum temperature) [1]. The experiment results also show that the ductile to brittle temperature increases as the fuel burnup increases. These results indicate that the current knowledge in cladding material property is insufficient to determine the structural performance of the cladding of high burnup fuel after it has been stored in a dry cask storage system for some time. The uncertainties in material property and the elevated ductile to brittle transition temperature impose a challenge to the storage cask and transportation packaging designs because the cask designs may not be able to rely on the structural integrity of the fuel assembly for control of fissile material, radiation source, and decay heat source distributions. The fuel may reconfigure during further storage and/or the subsequent transportation conditions. In addition, the fraction of radioactive materials available for release from spent fuel under normal condition of storage and transport may also change. The spent fuel storage and/or transportation packaging vendors, spent fuel shippers, and the regulator may need to consider this possible fuel reconfiguration and its impact on the packages' ability to meet the safety requirements of Part 72 and Part 71 of Title 10 of the Code of Federal Regulations. The United States Nuclear Regulatory Commission (NRC) is working with the scientists at Oak Ridge National Laboratory (ORNL) to assess the impact of fuel reconfiguration on the safety of the dry storage systems and transportation packages. The NRC Division of Spent Fuel Storage and Transportation has formed a task force to work on the safety and regulatory concerns in relevance to high burnup fuel storage and transportation. This paper discusses the staff's preliminary considerations on the safety implication of fuel reconfiguration with respect to nuclear safety (subcriticality control), radiation shielding, containment, the performance of the thermal functions of the packages, and the retrievability of the contents from regulatory perspective. (authors)},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = 2013,
month = 7
}

Conference:
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  • Available in abstract form only. Full text of publication follows: Finding timely resolutions of current regulatory issues related to spent fuel storage and transportation is one of the most important priorities for both industry and regulators. Spent fuel pools at many US power plants have either reached or are rapidly approaching full capacity, a condition made worse by the longer cooling time required for high burnup (>45 GWd/MTU) spent fuel compared to lower burnup fuel for which most spent fuel pools were designed to accommodate. Consequently, the need for the transfer of spent fuel to dry storage, with eventual transportationmore » to off-site interim storage facilities or to a permanent repository, has brought with it the need to cope with a number of regulatory issues that require significant lead time to resolve. In anticipation of this need, EPRI has, over the past several years, implemented a number of research programs, which include: (a) assessing the criticality risks during transportation; (b) evaluating the option of moderator exclusion; (c) participating in data gathering for implementation of full burnup credit; (d) evaluating the potential for fuel reconfiguration during transportation accidents; and (e) assessing the impact of fuel reconfiguration on spent fuel reactivity levels. The criteria by which the results of this program may be evaluated are the regulations contained in 10 CFR Parts 71 and 72 as well as in Standard Review Plans and Interim Staff Guidance (ISG) documents such as ISG-11, ISG-8 and ISG-19. Of these research programs, the fuel reconfiguration issue is the most complex because it requires long lead-time to develop the necessary material behavior models and analysis methods. To this end, the paper describes the results of EPRI's multi-year research program, with emphasis on the various phenomena that govern cladding thermo-mechanical behavior from the onset of placing spent fuel in dry storage casks to the consequences of hypothetical accidents on cladding failure and fuel reconfiguration. (authors)« less
  • The motivation for taking credit for fuel assembly burnup in spent-fuel storage rack design is obvious. Several pressurized water reactor facilities, beginning with the standardized nuclear unit power plant system plants (Callaway and Wolf Creek) have been licensed to install racks that take credit for burnup. Designing racks to take credit for burnup introduces several calculational complexities with respect to criticality that are not present in designing for fresh fuel storage. The criticality analyses are required to be performed with calculational methods and procedures that have been verified by comparison with experiments. Several experiments have been performed with unirradiated fuelmore » that included the major features of fuel racks. However, none has been performed with irradiated fuel. A final aspect of the two-region pool designs is assurance that only assemblies having the required burnup are stored in region 2.« less
  • Abstract not provided.
  • Finite element analysis (FEA) was used to investigate the impacts of interfacial bonding efficiency at pellet pellet and pellet clad interfaces on spent nuclear fuel (SNF) vibration integrity. The FEA simulation results were also validated and benchmarked with reverse bending fatigue test results on surrogate rods consisting of stainless steel (SS) tubes with alumina-pellet inserts. Bending moments (M) are applied to the FEA models to evaluate the system responses of the surrogate rods. From the induced curvature, , the flexural rigidity EI can be estimated as EI=M/ . The impacts of interfacial bonding efficiency on SNF vibration integrity include themore » moment carrying capacity distribution between pellets and clad and the impact of cohesion on the flexural rigidity of the surrogate rod system. The result also indicates that the immediate consequences of interfacial de-bonding are a load carrying capacity shift from the fuel pellets to the clad and a reduction of the composite rod flexural rigidity. Therefore, the flexural rigidity of the surrogate rod and the bending moment bearing capacity between the clad and fuel pellets are strongly dependent on the efficiency of interfacial bonding at the pellet pellet and pellet clad interfaces. The above-noted phenomenon was calibrated and validated by reverse bending fatigue testing using a surrogate rod system.« less