One of the significant issues yet to be resolved for using
burnup credit ~BUC! for spent nuclear fuel ~SNF! is establishing
a set of depletion parameters that produce an adequately conservative
representation of the fuel’s isotopic inventory. Depletion
parameters ~such as local power, fuel temperature, moderator temperature,
burnable poison rod history, and soluble boron concentration!
affect the isotopic inventory of fuel that is depleted in a
pressurized water reactor ~PWR!. However, obtaining the detailed
The effect of fixed absorbers on the reactivity of pressurized water reactor (PWR) spent nuclear fuel (SNF) in support of burnup-credit criticality safety analyses is examined. A fuel assembly burned in conjunction with fixed absorbers may have a higher reactivity for a given burnup than an assembly that has not used fixed absorbers. As a result, guidance on burnup credit, issued by the U.S. Nuclear Regulatory Commission's Spent Fuel Project Office, recommends restricting the use of burnup credit to assemblies that have not used burnable absorbers.
The purpose of this directory is to make available a convenient source of information on package designs approved by the U.S. Nuclear Regulatory Commission. To assist in identifying packages, an index by Model Number and corresponding Certificate of Compliance Number is included at the front of Volume 2. The report includes all package designs approved prior to the publication date of the directory as of September 2013.
This guidance is aimed at helping readers understand the permitting and other requirements specific to Radioactive Substances Regulation (RSR). The RSR regime covers
- more than one European Directive, parts of which are also implemented by other regulatory regimes which, to an extent, complement RSR;
- various Government policies and strategies; and
Nuclear waste disposal in the USA is a difficult policy issue infused with
science, technology, and politics. This issue provides an example of the co-production
of scientific knowledge and politics through public policy. The proponents of a
repository site at Yucca Mountain, Nevada, argue that their decision to go ahead
with the site is based on ‘sound science’, but the science they use to uphold their
decision is influenced by politics. In turn, the politics of site selection has been altered
Beginning with the role of "stakeholders" - those whose interests are, knowingly or unknowingly, affected - in the siting of noxious facilities, this paper seeks to develop principles for acceptable and democratically arrived at polices related to problems associated with advances in and products of science and technology. Although widely regarded as a necessary condition for success, the principles underpinning stakeholder involvement, such as representativeness, are often violated in practice.
U.S. efforts to site and construct a deep geologic repository for used fuel and high level radioactive waste (HLW) proceeded sporadically over a three-decade period from the late 1950s until 1982, when the U.S. Congress enacted the Nuclear Waste Policy Act (NWPA) codifying a national approach for developing a deep geologic repository. Amendment of the NWPA in 1987 resulted in a number of dramatic changes in direction for the U.S. program, most notably the selection of Yucca Mountain as the only site of the three remaining candidates for continued investigation.
The structure of this National Report complies, to the greatest adjustment possible, with the
Guidelines Regarding the Form and Structure of National Reports approved in the
Preparatory Meeting held in Vienna in December 2001.
Section A includes a general introduction to the report, and a reference to the National
Program which contemplates spent fuel and radioactive waste management and the treatment
of wastes that originate from Mining and Uranium Processing.
The U.S. industry’s limited efforts at licensing transportation packages characterized as “highcapacity,”
or containing “high-burnup” (>45 GWd/MTU) commercial spent nuclear fuel
(CSNF), or both, have not been successful considering existing spent-fuel inventories that will
have to be eventually transported. A holistic framework is proposed for resolving several CSNF
transportation issues. The framework considers transportation risks, spent-fuel and cask-design
The effective termination of the Yucca Mountain program by the U.S. Administration in 2009 has further delayed the construction and operation of a permanent disposal facility for used fuel and high level radioactive waste (HLW) in the United States. In concert with this decision, the President directed the Energy Secretary to establish the Blue Ribbon Commission on America's Nuclear Future to review and provide recommendations on options for managing used fuel and HLW.
On March 22, 1975, a fire was experienced at the Browns Ferry Nuclear Plant near Decatur, Alabama. The Special Review Group was established by the Executive Director for Operations of the Nuclear Regulatory Commission (NRC) soon after the fire to identify the lessons learned from this event and to make recommendations for the future in the light of these lessons. Unless further developments indicate a need to reconvene the Review Group, its task is considered complete with the publication of this report.
On March 22, 1975, a fire at the Browns Ferry Nuclear Plant caused a shutdown of Units 1 and 2. The facility subsequent to the shutdown was found to have incurred substantial damage to power, control, and instrumentation wiring. All three units are presently in the shutdown condition with the fuel removed from the vessels for Units 1 and 2; the Unit 3 reactor is still under construction with operation for that unit scheduled for early 1976.
Section 208 of the Energy Reorganization Act of 1974, as amended (Public Law 93-438), defines an "abnormal occurrence" (AO) as an unscheduled incident or event that the U.S. Nuclear Regulatory Commission (NRC) determines to be significant from the standpoint of public health or safety. The Federal Reports Elimination and Sunset Act of 1995 (Public Law 104-66) requires that the NRC report AOs to Congress annually.
The requirements of ANSI/ANS 8.1 specify that calculational methods for away-from-reactor
(AFR) criticality safety analyses be validated against experimental measurements. If credit for the
negative reactivity of the depleted (or spent) fuel isotopics is desired, it is necessary to benchmark
computational methods against spent fuel critical configurations. This report summarizes a portion
of the ongoing effort to benchmark AFR criticality analysis methods using selected critical
configurations from commercial pressurized-water reactors (PWR).
Utilization of burnup credit in criticality safety analysis for long-term disposal of spent
nuclear fuel allows improved design efficiency and reduced cost due to the large mass of fissile
material that will be present in the repository. Burnup-credit calculations are based on depletion
calculations that provide a conservative estimate of spent fuel contents (in terms of criticality
potential), followed by criticality calculations to assess the value of the effective neutron
The isotopic composition of mixed-oxide fuel (fabricated with both uranium and plutonium
isotopes) discharged from reactors is of interest to the Fissile Material Disposition Program. The
validation of depletion codes used to predict isotopic compositions of MOX fuel, similar to studies
concerning uranium-only fueled reactors, thus, is very important. The EEI-Westinghouse Plutonium
Recycle Demonstration Program was conducted to examine the use of MOX fuel in the San Onofre
The purpose of this design analysis is to determine the accuracy of the SAS2H module of SCALE 4.3 in predicting isotopic concentrations of spent fuel assemblies. The objective is to develop a methodology for modeling assemblies similar to those evaluated within this analysis and to establish the consistency of SAS2H predictions. The results of this analysis may then be applied to future depletion calculations using SAS2H in which no measurements are available.
Spent Fuel Project Office, Interim Staff Guidance - 8, Revision 2 - Burnup Credit in the Criticality Safety Analyses of PWR Spent Fuel in Transport
and Storage Casks
The requirements of ANSI/ANS 8.1 specify that calculational methods for away-from-reactor
criticality safety analyses be validated against experimental measurements. If credit for the negative
reactivity of the depleted (or spent) fuel isotopics is desired, it is necessary to benchmark
computational methods against spent fuel critical configurations. This report summarizes a portion
of the ongoing effort to benchmark away-from-reactor criticality analysis methods using critical
configurations from commercial pressurized-water reactors.
The purpose of this design analysis is to determine the accuracy of the SAS2H module of SCALE 4.3 in predicting isotopic concentrations of spent fuel assemblies. The objective is to develop a methodology for modeling assemblies similar to those evaluated within this analysis and to establish the consistency of SAS2H predictions. The results of this analysis may then be applied to future depletion calculations using SAS2H in which no measurements are available.
This calculation file provides comparisons of one- and two-dimensional methods for calculating the isotopic content of spent nuclear fuel. The one-dimensional methods use the SAS2H sequence of SCALE 4.4a (Reference 7.1) and the SAS2 sequence of SCALE 5.0 (Reference 7.2). The two-dimensional method uses the TRITON control module along with the T-DEPL sequence of SCALE 5.0 (Reference 7.3). The SAS2H results for SCALE 4.4a are taken from Reference 7.4. Data from previous two-dimensional calculations (Reference 7.5) using CASM03 will also be used for comparisons with TRITON.
The purpose of this calculation is to document the Three Mile Island Unit 1 pressurized water reactor {PWR) reactivity calculations performed as part o f the commercial reactor critical (CRC) evaluation program. CRC evaluation reactivity calculations are performed at a number of statepoints, representing reactor start-up critical conditions at either beginning of life (BOL), beginning of cycle (BOC), or mid- cycle when the reactor resumed operation after a shutdown.
The purpose of this calculation is to document the Sequoyah Unit 2 pressurized water reactor (PWR) fuel depletion calculations performed as part of the commercial reactor critical (CRC) evaluation program. The CRC evaluations support the development and validation of the neutronics models used for criticality analyses involving commercial spent nuclear fuel in a geologic repository.
