This report describes a novel approach developed at the Oak Ridge National Laboratory
(ORNL) for the estimation of the uncertainty in the prediction of the neutron multiplication factor
for spent nuclear fuel. This technique focuses on burnup credit, where credit is taken in criticality
safety analysis for the reduced reactivity of fuel irradiated in and discharged from a reactor.
Validation methods for burnup credit have attempted to separate the uncertainty associated with

This report attempts to summarize and consolidate the existing knowledge on axial
burnup distribution issues that are important to burnup credit criticality safety calculations.
Recently released Nuclear Regulatory Commission (NRC) staff guidance permits limited burnup
credit, and thus, has prompted resolution of the axial burnup distribution issue. The reactivity
difference between the neutron multiplication factor (keff) calculated with explicit representation

This vintage 1990 document presents the results of WESTON'S preliminary assessment of the feasibility of several alternative fuel-transfer and storage concepts that have the potential for early spent-fuel acceptance at an MRS facility. The feasibility study was part of a series of studies conducted by the U.S. Department of Energy (DOE) during the late 1980's and early 1990's in an effort to establish an MRS design configuration.

The Department of Energy (DOE) is studying a site at Yucca Mountain, Nevada, for a
permanent underground repository for highly radioactive spent fuel from nuclear reactors,
but delays have pushed back the facility’s opening date to 2010 at the earliest. In the
meantime, spent fuel is accumulating at U.S. nuclear plant sites at the rate of about 2,000
metric tons per year. Major options for managing those growing quantities of nuclear spent
fuel include continued storage at reactors, construction of a DOE interim storage site near

This manual discusses the cost estimating routines used in Version (V) 6.0 of the Total System
Model (TSM) as described in the TSM User Manual (BSC 2007a). The TSM estimates costs
during the simulation of the Civilian Radioactive Waste Management System (CRWMS)
mission. The TSM is not intended to provide a full Total System Life Cycle Cost (TSLCC)
evaluation tool but focuses on the CRWMS Waste Acceptance, Storage, and Transportation
(WAST) elements reported for the TSLCC in Reference BSC 2003a. This manual also

Confidence in the long-term safety of deep geological disposal, and the ways in which this
confidence can be obtained and communicated, are topics of great importance to the radioactive waste
management community.1
The technical aspects of confidence have been the subject of considerable debate, especially
the concept of model validation. It has, for example, been pointed out that it is impossible to describe
fully the evolution of an open system, such as a repository and its environment, that cannot be

This report describes the calculation method developed for the projection of future utility spent nuclear fuel (SNF) discharges in regard to their timing, quantity, burnup, and initial enrichment. This projection method complements the utility-supplied RW-859 data on historic discharges and short-term projections of SNF discharges by providing long-term projections that complete the total life cycle of discharges for each of the current U.S. nuclear power reactors.

Transport of the damaged core materials from the Unit 2 reactor of the Three
Mile Island Nuclear Power Station (TMI-2) to the Idaho National Engineering Laboratory
(INEL) for examination and storage presented many technical and institutional
challenges, including assessing the ability to transport the damaged core;
removing and packaging core debris in ways suitable for transport; developing a
transport package that could both meet Federal regulations and interface with the

Technical development on burn-up credit for spent LWR fuels had been performed at JAERI since
1990 under the contract with Science and Technology Agency of Japan entitled ‘Technical Development on
Criticality Safety Management for Spent LWR Fuels.’ Main purposes of this work are to obtain the
experimental data on criticality properties and isotopic compositions of spent LWR fuels and to verify burnup
and criticality calculation codes. In this work three major experiments of exponential experiments for