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Title: Long-lived activation products in reactor materials

Abstract

The purpose of this program was to assess the problems posed to reactor decommissioning by long-lived activation products in reactor construction materials. Samples of stainless steel, vessel steel, concrete, and concrete ingredients were analyzed for up to 52 elements in order to develop a data base of activatable major, minor, and trace elements. Large compositional variations were noted for some elements. Cobalt and niobium concentrations in stainless steel, for example, were found to vary by more than an order of magnitude. A thorough evaluation was made of all possible nuclear reactions that could lead to long lived activation products. It was concluded that all major activation products have been satisfactorily accounted for in decommissioning planning studies completed to date. A detailed series of calculations was carried out using average values of the measured compositions of the appropriate materials to predict the levels of activation products expected in reactor internals, vessel walls, and bioshield materials for PWR and BWR geometries. A comparison is made between calculated activation levels and regulatory guidelines for shallow land disposal according to 10 CFR 61. This analysis shows that PWR and BWR shroud material exceeds the Class C limits and is, therefore, generally unsuitable for near-surfacemore » disposal. The PWR core barrel material approaches the Class C limits. Most of the remaining massive components qualify as either Class A or B waste with the bioshield clearly Class A, even at the highest point of activation. Selected samples of activated steel and concrete were subjected to a limited radiochemical analysis program as a verification of the computer model. Reasonably good agreement with the calculations was obtained where comparison was possible. In particular, the presence of /sup 94/Nb in activated stainless steel at or somewhat above expected levels was confirmed.« less

Authors:
; ; ; ; ; ; ;
Publication Date:
Research Org.:
Pacific Northwest Lab., Richland, WA (USA)
OSTI Identifier:
6776358
Alternate Identifier(s):
OSTI ID: 6776358; Legacy ID: TI84017215
Report Number(s):
NUREG/CR-3474; PNL-4824
ON: TI84017215
DOE Contract Number:  
AC06-76RL01830
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
22 GENERAL STUDIES OF NUCLEAR REACTORS; 21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS; BWR TYPE REACTORS; RADIOACTIVATION; REACTOR DECOMMISSIONING; PWR TYPE REACTORS; REACTOR MATERIALS; CONCRETES; STAINLESS STEELS; STEELS; ALLOYS; BUILDING MATERIALS; CHROMIUM ALLOYS; CORROSION RESISTANT ALLOYS; DECOMMISSIONING; IRON ALLOYS; IRON BASE ALLOYS; MATERIALS; REACTORS; WATER COOLED REACTORS; WATER MODERATED REACTORS 220900* -- Nuclear Reactor Technology-- Reactor Safety; 210100 -- Power Reactors, Nonbreeding, Light-Water Moderated, Boiling Water Cooled; 210200 -- Power Reactors, Nonbreeding, Light-Water Moderated, Nonboiling Water Cooled

Citation Formats

Evans, J.C., Lepel, E.L., Sanders, R.W., Wilkerson, C.L., Silker, W., Thomas, C.W., Abel, K.H., and Robertson, D.R. Long-lived activation products in reactor materials. United States: N. p., 1984. Web. doi:10.2172/6776358.
Evans, J.C., Lepel, E.L., Sanders, R.W., Wilkerson, C.L., Silker, W., Thomas, C.W., Abel, K.H., & Robertson, D.R. Long-lived activation products in reactor materials. United States. doi:10.2172/6776358.
Evans, J.C., Lepel, E.L., Sanders, R.W., Wilkerson, C.L., Silker, W., Thomas, C.W., Abel, K.H., and Robertson, D.R. Wed . "Long-lived activation products in reactor materials". United States. doi:10.2172/6776358. https://www.osti.gov/servlets/purl/6776358.
@article{osti_6776358,
title = {Long-lived activation products in reactor materials},
author = {Evans, J.C. and Lepel, E.L. and Sanders, R.W. and Wilkerson, C.L. and Silker, W. and Thomas, C.W. and Abel, K.H. and Robertson, D.R.},
abstractNote = {The purpose of this program was to assess the problems posed to reactor decommissioning by long-lived activation products in reactor construction materials. Samples of stainless steel, vessel steel, concrete, and concrete ingredients were analyzed for up to 52 elements in order to develop a data base of activatable major, minor, and trace elements. Large compositional variations were noted for some elements. Cobalt and niobium concentrations in stainless steel, for example, were found to vary by more than an order of magnitude. A thorough evaluation was made of all possible nuclear reactions that could lead to long lived activation products. It was concluded that all major activation products have been satisfactorily accounted for in decommissioning planning studies completed to date. A detailed series of calculations was carried out using average values of the measured compositions of the appropriate materials to predict the levels of activation products expected in reactor internals, vessel walls, and bioshield materials for PWR and BWR geometries. A comparison is made between calculated activation levels and regulatory guidelines for shallow land disposal according to 10 CFR 61. This analysis shows that PWR and BWR shroud material exceeds the Class C limits and is, therefore, generally unsuitable for near-surface disposal. The PWR core barrel material approaches the Class C limits. Most of the remaining massive components qualify as either Class A or B waste with the bioshield clearly Class A, even at the highest point of activation. Selected samples of activated steel and concrete were subjected to a limited radiochemical analysis program as a verification of the computer model. Reasonably good agreement with the calculations was obtained where comparison was possible. In particular, the presence of /sup 94/Nb in activated stainless steel at or somewhat above expected levels was confirmed.},
doi = {10.2172/6776358},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1984},
month = {8}
}