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Title: Use of post-Chernobyl data from Norway to validate the long-term exposure pathway models in the accident consequence code MACCS

Abstract

This paper describes a task performed for the US Nuclear Regulatory Commission (NRC), consisting of using post-Chernobyl data from Norway to verify or find areas for possible improvement in the chronic exposure pathway models utilized in the NRC's program for probabilistic risk analysis, level 3, of the MELCOR accident consequence code system (MACCS), developed at Sandia National Laboratories, Albuquerque, New Mexico. Because of unfortunate combinations of weather conditions, the levels of Chernobyl fallout in parts of Norway were quite high, with large areas contaminated to more than 100 kBq/m[sup 2] of radioactive cesium. Approximately 6% of the total amount of radioactive cesium released from Chernobyl is deposited on Norwegian territory, according to a countrywide survey performed by the Norwegian National Institute for Radiation Hygiene. Accordingly, a very large monitoring effort was carried out in Norway, and some of the results of this effort have provided important new insights into the ways in which radioactive cesium behaves in the environment. In addition to collection and evaluation of post-Chernobyl monitoring results, some experiments were also performed as part of the task. Some experiments performed pre-Chernobyl were also relevant, and some conclusions could be drawn from these. In most connections, the data availablemore » show the models and data in MACCS to be appropriate. A few areas where the data indicate that the MACCS approach is inadequate are, however, also pointed out in the paper.« less

Authors:
 [1]
  1. (Inst. for Energiteknikk, Kjeller (Norway))
Publication Date:
OSTI Identifier:
5065369
Resource Type:
Journal Article
Resource Relation:
Journal Name: Nuclear Technology; (United States); Journal Volume: 105:3
Country of Publication:
United States
Language:
English
Subject:
22 GENERAL STUDIES OF NUCLEAR REACTORS; ENVIRONMENTAL EXPOSURE PATHWAY; MATHEMATICAL MODELS; REACTOR ACCIDENTS; M CODES; BIOLOGICAL AVAILABILITY; CHERNOBYLSK-4 REACTOR; DATA ANALYSIS; FALLOUT; RADIATION MONITORING; REACTOR SAFETY; RISK ASSESSMENT; ACCIDENTS; COMPUTER CODES; ENRICHED URANIUM REACTORS; GRAPHITE MODERATED REACTORS; LWGR TYPE REACTORS; MONITORING; POWER REACTORS; REACTORS; SAFETY; THERMAL REACTORS; WATER COOLED REACTORS 220900* -- Nuclear Reactor Technology-- Reactor Safety; 220200 -- Nuclear Reactor Technology-- Components & Accessories

Citation Formats

Tveten, U. Use of post-Chernobyl data from Norway to validate the long-term exposure pathway models in the accident consequence code MACCS. United States: N. p., 1994. Web.
Tveten, U. Use of post-Chernobyl data from Norway to validate the long-term exposure pathway models in the accident consequence code MACCS. United States.
Tveten, U. 1994. "Use of post-Chernobyl data from Norway to validate the long-term exposure pathway models in the accident consequence code MACCS". United States. doi:.
@article{osti_5065369,
title = {Use of post-Chernobyl data from Norway to validate the long-term exposure pathway models in the accident consequence code MACCS},
author = {Tveten, U.},
abstractNote = {This paper describes a task performed for the US Nuclear Regulatory Commission (NRC), consisting of using post-Chernobyl data from Norway to verify or find areas for possible improvement in the chronic exposure pathway models utilized in the NRC's program for probabilistic risk analysis, level 3, of the MELCOR accident consequence code system (MACCS), developed at Sandia National Laboratories, Albuquerque, New Mexico. Because of unfortunate combinations of weather conditions, the levels of Chernobyl fallout in parts of Norway were quite high, with large areas contaminated to more than 100 kBq/m[sup 2] of radioactive cesium. Approximately 6% of the total amount of radioactive cesium released from Chernobyl is deposited on Norwegian territory, according to a countrywide survey performed by the Norwegian National Institute for Radiation Hygiene. Accordingly, a very large monitoring effort was carried out in Norway, and some of the results of this effort have provided important new insights into the ways in which radioactive cesium behaves in the environment. In addition to collection and evaluation of post-Chernobyl monitoring results, some experiments were also performed as part of the task. Some experiments performed pre-Chernobyl were also relevant, and some conclusions could be drawn from these. In most connections, the data available show the models and data in MACCS to be appropriate. A few areas where the data indicate that the MACCS approach is inadequate are, however, also pointed out in the paper.},
doi = {},
journal = {Nuclear Technology; (United States)},
number = ,
volume = 105:3,
place = {United States},
year = 1994,
month = 3
}
  • The task described in this paper was performed for the U.S. Nuclear Regulatory Commission. The chronic exposure pathway models implemented in the MELCOR Accident Consequence Code System (MACCS) were compared to post-Chernobyl data from various sources, though mainly from Norway, for verification or identification of areas for possible improvement. The reason for choosing data from Norway for this purpose is partly that Chernobyl fallout levels in Norway are higher than in any other country in western Europe and partly that Norway has been deeply involved in many different types of experiments examining the behavior of radioactive materials in the environmentmore » since the early 1960s.« less
  • The purpose of this report is to document the results of the work performed by the author in connection with the following task, performed for US Nuclear Regulatory Commission, (USNRC) Office of Nuclear Regulatory Research, Division of Systems Research: MACCS Chronic Exposure Pathway Models: Review the chronic exposure pathway models implemented in the MELCOR Accident Consequence Code System (MACCS) and compare those models to the chronic exposure pathway models implemented in similar codes developed in countries that are members of the OECD. The chronic exposures concerned are via: the terrestrial food pathways, the water pathways, the long-term groundshine pathway, andmore » the inhalation of resuspended radionuclides pathway. The USNRC has indicated during discussions of the task that the major effort should be spent on the terrestrial food pathways. There is one chapter for each of the categories of chronic exposure pathways listed above.« less
  • Even now, 10 yr after the Chernobyl accident, the consequences are felt in some Western European countries, particularly in Norway, where considerable yearly economic consequences to Norwegian agriculture are incurred. This paper summarizes these economic consequences year by year over the 10-yr period and describes the various countermeasures adopted to reduce the consequences. The consequences are mainly connected to the production of mutton and reindeer meat.
  • In Norway, external doses of radiation resulting from fallout from the Chernobyl nuclear accident were estimated from detailed measurements, including soil deposition patterns. Internal doses were estimated from measurements of radioactive cesium in meat and milk supplies. The doses were calculated as average monthly doses for each of 454 municipalities during 36 consecutive months after the accident in spring 1986. Prospectively collected data on all newborns listed in the Medical Birth Registry of Norway who were conceived in the period May 1983-April 1989 were used to assess possible dose-response relations between estimated external and food-based exposures and congenital malformations andmore » some other conditions. A positive association was observed between total radiation dose (external plus food-based) and hydrocephaly, while a negative association was observed for Down's syndrome. However, an important conclusion of the study was that no associations were found for conditions previously reported to be associated with radiation, i.e., small head circumference, congenital cataracts, anencephaly, spina bifida, and low birth weight. Potential sources of bias, including exposure misclassification and incomplete ascertainment of cases, are discussed.« less
  • The longterm behavior of {sup 137}Cs in milk of a Bavarian farm (farm A) deposited as a consequence of the Chernobyl accident has been followed from April 1986 until August 1994. On the basis of activity measurements in milk and feed, transfer coefficients for the different seasons have been estimated in order to see any changes in transfer behavior (aging effect) of {sup 137}Cs with time. The influence of different grazing regimes has been tested by comparison of activity concentrations in milk and pasture grass in one farm (farm A with rotational grazing regime) with that of a nearby farmmore » (farm B with continuous grazing regime) over a complete grazing season by frequent measurements in 1993. Though the farms are located only 4 km apart, have similar soils, and were contaminated to the same extent by the Chernobyl fallout, tenfold lower {sup 137}Cs activity concentrations in milk have been observed in farm B. This finding seems to be partly due to the influence of a different grazing intensity. 15 refs., 4 figs., 3 tabs.« less