Background To determine whether current and former construction workers are at
significant risk for occupational illnesses from work at the Department of Energy’s (DOE)
nuclear weapons facilities, screening programs were undertaken at the Hanford Nuclear
Reservation, Oak Ridge Reservation, and the Savannah River Site.

The purpose of the material degradation and release (MDR) model is to predict the fate of the waste package materials, specifically the retention or mobilization of the radionuclides and the neutron-absorbing material as a function of time after the breach of a waste package during the 10,000 years after repository closure. The output of this model is used directly to assess the potential for a criticality event inside the waste package due to the retention of the radionuclides combined with a loss of the neutron-absorbing material.

This guidance manual provides the NRC staff methodology for calculating parameters for limiting conditions of operation required in the radiological effluent Technical Specifications for light-water-cooled nuclear power plants. it provides guidance in using the model specifications reported in NUREG-0472 (Revision 1)*, and NUREG-0473 (Revision 1)*, applicable to operating PWR and BWR licensees, and users of the Standard Technical Specifications packages available for various vendor designs.

The purpose and scope of this model report is to document models for general and localized corrosion of the waste package outer barrier (WPOB) to be used in evaluating long-term waste package performance in the total system performance assessment (TSPA). The waste package design for the license application is a double-wall waste package placed underneath a protective drip shield (SNL 2007 [DIRS 179394]; SNL 2007 [DIRS 179354]). The WPOB will be constructed of Alloy 22 (UNS N06022) (SNL 2007 [DIRS 179567], Section 4.1.1.6), a highly corrosion-resistant nickel-based alloy.

The Nuclear Waste Policy Act of 1982 (the Act), established a
step-by-step process for the siting of the nation's first repository for
high-level radioactive waste and spent fuel. The Act gave the Department of
Energy (DOE) the primary responsibility for conducting this siting process.
The first step in the process laid out in the Act was the development by
the DOE, with the concurrence of the Nuclear Regulatory Commission (NRC), of
general guidelines to be used by the Secretary of the DOE (the Secretary) in

The purpose of this document is to provide the requirements rationale for the current version of the Preliminary Transportation, Aging and Disposal Canister System Performance Specification; WMO-TADCS-000001.

Stress corrosion cracking (SCC) is one of the most common corrosion-related causes for premature breach of metal structural components. SCC is the initiation and propagation of cracks in structural components due to three factors that must be present simultaneously (Jones 1992 [DIRS 169906], Section 8.1): metallurgical susceptibility, critical environment, and sustained tensile stresses.

This report was developed in accordance with the requirements in Technical Work Plan for Postclosure Waste Form Modeling (BSC 2005 [DIRS 173246]). The purpose of the in-package chemistry model is to predict the bulk chemistry inside of a breached waste package and to provide simplified expressions of that chemistry as a function of time after breach to Total Systems Performance Assessment for the License Application (TSPA-LA).

Background Medical screening programs were begun in 1996 and 1997 at three Department
of Energy (DOE) nuclear weapons facilities (Hanford Nuclear Reservation, Oak
Ridge, and the Savannah River Site) to evaluate whether current and former construction
workers are at significant risk for occupational illnesses. The focus of this report is
pneumoconiosis associated with exposures to asbestos and silica among workers enrolled
in the screening programs through September 30, 2001.

The purpose of this report is to evaluate the potential for penetration of the Alloy 22 (UNS N06022) waste package outer barrier by localized corrosion due to the deliquescence of soluble constituents in dust present on waste package surfaces. The results support a recommendation to exclude deliquescence-induced localized corrosion (pitting or crevice corrosion) of the outer barrier from the total system performance assessment for the license application (TSPA-LA).

Background Medical screening programs at three Departments of Energy (DOE)
nuclear weapons facilities (Hanford Nuclear Reservation, Oak Ridge, and the Savannah
River Site) have included audiometric testing since approximately 1996. This report
summarizes hearing evaluations through March 31, 2003.
Methods Occupational examinations included a medical history, limited physical
examination, and tests for medical effects from specific hazards, including audiometric
testing. Hearing thresholds by frequency for DOE workers were compared to agestandardized

The repository design includes a drip shield (BSC 2004 [DIRS 168489]) that provides protection for the waste package both as a barrier to seepage water contact and a physical barrier to potential rockfall.
The purpose of the process-level models developed in this report is to model dry oxidation, general corrosion, and localized corrosion of the drip shield plate material, which is made of Ti Grade 7. This document is prepared ·according to Technical Work Plan For: Regulatory Integration Modeling and Analysis of the Waste Form and Waste Package (BSC 2004 [DIRS 171583]).

Background The U.S. Department of Energy (DOE) established medical screening
programs at the Hanford Nuclear Reservation, Oak Ridge Reservation, the Savannah
River Site, and the Amchitka site starting in 1996.Workers participating in these programs
have been followed to determine their vital status and mortality experience through
December 31, 2004.
Methods A cohort of 8,976 former construction workers from Hanford, Savannah River,
Oak Ridge, and Amchitka was followed using the National Death Index through December

The purpose of this analysis is to evaluate the types of defects or imperfections that could occur in a waste package or a drip shield and potentially lead to its early failure, and to estimate a probability of undetected occurrence for each type. An early failure is defined as the through-wall penetration of a waste package or drip shield due to manufacturing or handling-induced defects, at a time earlier than would be predicted by mechanistic degradation models for a defect-free waste package or drip shield.

Hydrogen-induced cracking is characterized by the decreased ductility and fracture toughness of a material due to the absorption of atomic hydrogen in the metal crystal lattice. Corrosion is the source of hydrogen generation. For the current design of the engineered barrier without backfill, hydrogen-induced cracking may be a concern because the titanium drip shield can be galvanically coupled to rock bolts (or wire mesh), which may fall onto the drip shield, thereby creating conditions for hydrogen production by electrochemical reaction.

The purpose of this report is to evaluate the potential for penetration of the Alloy 22 (UNS N06022) waste package outer barrier by localized corrosion due to the deliquescence of soluble constituents in dust present on waste package surfaces. The results support a recommendation to exclude deliquescence-induced localized corrosion (pitting or crevice corrosion) of the outer barrier from the total system performance assessment for the license application (TSPA-LA).