Presented at the NEI Used Fuel Management Conference, St. Petersburg, FL, May 7-9, 2013

Taking credit for the reduced reactivity of spent nuclear fuel (SNF) in criticality analyses is referred to as burnup credit (BUC). Criticality safety evaluations require validation of the computational methods with critical experiments that are as similar as possible to the safety analysis models, and for which the keff values are known. This poses a challenge for validation of BUC criticality analyses, as critical experiments with actinide and fission product (FP)

The issue of interim storage of used (spent)1 fuel is dependent on a number of key factors, some
of which are not known at this time but are the subject of this study. The first is whether or not
the Yucca Mountain Project continues or is cancelled such that it may be able to receive spent
fuel from existing and decommissioned nuclear power stations. The second is whether the United
States will pursue a policy of reprocessing and recycling nuclear fuel. The reprocessing and

Presented at the NEI Used Fuel Management Conference, St. Petersburg, FL, May 7-9, 2013

Presented at the NEI Used Fuel Management Conference, St. Petersburg, FL, May 7-9, 2013

This report proposes and documents a computational benchmark problem for the estimation of the additional reactivity margin available in spent nuclear fuel (SNF) from fission products and minor actinides in a burnupcredit storage/transport environment, relative to SNF compositions containing only the major actinides. The benchmark problemlconfiguration is a generic burnup credit cask designed to hold 32 pressurized water reactor (PWR) assemblies.

Presented at the NEI Used Fuel Management Conference, St. Petersburg, FL, May 7-9, 2013

Presented at the NEI Used Fuel Management Conference, St. Petersburg, FL, May 7-9, 2013

This report provides details of dry storage cask systems and contents in U.S. for commercial light water
reactor fuel. Section 2 contains details on the canisters used to store approximately 86% of assemblies in
dry storage in the U.S. Transport cask details for bare fuels, dual purpose casks and canister transport
casks are included in Section 3. Section 4 details the inventory of those shutdown sites without any
operating reactors. Information includes the cask type deployed, transport license and status as well as

Presentation made at International Conference on The Management of Spent Nuclear Fuel from Nuclear Power Reactors, An Integrated approach to the Back-End of the Fuel Cycle (IAEA-CN-226). The purpose of the conference was to highlight the importance of an integrated long-term approach to the management of spent fuel from nuclear power reactors.

Analytical methods, described in this report, are used to
systematically determine experimental fuel sub-batch
reactivities as a function of burnup. Fuel sub-batch reactivities
are inferred using more than 600 in-core pressurized water
reactor (PWR) flux maps taken during 44 cycles of operation
at the Catawba and McGuire nuclear power plants. The
analytical methods systematically search for fuel sub-batch
reactivities that minimize differences between measured and
computed reaction rates, using Studsvik Scandpower’s

Progress toward developing a technical basis for a cost-effective burnup credit methodology for
spent nuclear fuel with initial U-235 enrichment up to 5% is presented. Present regulatory
practices provide as much burnup credit flexibility as can be currently expected. Further progress
is achievable by incorporating the negative reactivity effects of a subset of neutron-absorbing
fission product isotopes. Progress also depends on optimizing the procedure for establishing the

In 1999, the United States Nuclear Regulatory Commission (U.S. NRC) initiated a research program
to support the development of technical bases and guidance that would facilitate the implementation of burnup
credit into licensing activities for transport and dry cask storage. This paper reviews the following major areas of
investigation: (1) specification of axial burnup profiles, (2) assumption on cooling time, (3) allowance for
assemblies with fixed and removable neutron absorbers, (4) the need for a burnup margin for fuel with initial

The amount of spent fuel stored on-site at commercial nuclear reactors will continue to accumulate—increasing by about 2,000 metric tons per year and likely more than doubling to about 140,000 metric tons—before it can be moved off-site, because storage or disposal facilities may take decades to develop. In examining centralized storage or permanent disposal options, GAO found that new facilities may take from 15 to 40 years before they are ready to begin accepting spent fuel. Once an off-site facility is available, it will take several more decades to ship spent fuel to that facility.

The U.S. Nuclear Waste Technical Review Board (Board) is tasked by the amendments to the Nuclear Waste Policy Act of 1982 to independently evaluate U. S. Department of Energy (DOE) technical activities for managing and disposing of used nuclear fuel and high-level radioactive waste. This report was prepared to inform DOE and Congress about the current state of the technical basis for extended dry storage1 of used fuel and its transportation following storage.