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Title: Radiological characterization of spent control rod assemblies

This document represents the final report of an ongoing study to provide radiological characterizations, classifications, and assessments in support of the decommissioning of nuclear power stations. This report describes the results of non-destructive and laboratory radionuclide measurements, as well as waste classification assessments, of BWR and PWR spent control rod assemblies. The radionuclide inventories of these spent control rods were determined by three separate methodologies, including (1) direct assay techniques, (2) calculational techniques, and (3) by sampling and laboratory radiochemical analyses. For the BWR control rod blade (CRB) and PWR burnable poison rod assembly (BPRA), {sup 60}Co and {sup 63}Ni, present in the stainless steel cladding, were the most abundant neutron activation products. The most abundant radionuclide in the PWR rod cluster control assembly (RCCA) was {sup 108m}Ag (130 yr halflife) produced in the Ag-In-Cd alloy used as the neutron poison. This radionuclide will be the dominant contributor to the gamma dose rate for many hundreds of years. The results of the direct assay methods agree very well ({+-}10%) with the sampling/radiochemical measurements. The results of the calculational methods agreed fairly well with the empirical measurements for the BPRA, but often varied by a factor of 5 to 10 formore » the CRB and the RCCA assemblies. If concentration averaging and encapsulation, as allowed by 10CFR61.55, is performed, then each of the entire control assemblies would be classified as Class C low-level radioactive waste.« less
Authors:
; ; ; ;  [1]
  1. Pacific Northwest Lab., Richland, WA (United States)
Publication Date:
OSTI Identifier:
125115
Report Number(s):
NUREG/CR--6390; PNL--10806
ON: TI96001903; TRN: 96:000028
DOE Contract Number:
AC06-76RL01830
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: Oct 1995
Research Org:
Nuclear Regulatory Commission, Washington, DC (United States). Div. of Regulatory Applications; Pacific Northwest Lab., Richland, WA (United States)
Sponsoring Org:
Nuclear Regulatory Commission, Washington, DC (United States)
Country of Publication:
United States
Language:
English
Subject:
22 NUCLEAR REACTOR TECHNOLOGY; 21 NUCLEAR POWER REACTORS AND ASSOCIATED PLANTS; 05 NUCLEAR FUELS; CONTROL ELEMENTS; NONDESTRUCTIVE ANALYSIS; BWR TYPE REACTORS; REACTOR DECOMMISSIONING; RADIOACTIVE WASTE MANAGEMENT; PWR TYPE REACTORS; NUCLEAR POWER PLANTS; LOW-LEVEL RADIOACTIVE WASTES; RADIOASSAY; RADIOCHEMICAL ANALYSIS; COBALT 60; NICKEL 63; SILVER 108; RADIOACTIVE WASTE DISPOSAL; ENCAPSULATION; RADIOACTIVE WASTE PROCESSING