ML19289E434
| ML19289E434 | |
| Person / Time | |
|---|---|
| Issue date: | 03/16/1979 |
| From: | Dullingford M, Roberts I NRC OFFICE OF NUCLEAR REGULATORY RESEARCH (RES), NRC OFFICE OF STANDARDS DEVELOPMENT |
| To: | Dircks W, Levine S, Minogue R NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS), NRC OFFICE OF NUCLEAR REGULATORY RESEARCH (RES), NRC OFFICE OF STANDARDS DEVELOPMENT |
| Shared Package | |
| ML19289E435 | List: |
| References | |
| NUDOCS 7904180171 | |
| Download: ML19289E434 (3) | |
Text
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UNITED STATES 8
NUCLEAR REGULATORY COMMISSION M'
.E WASHINGTON, D. C. 20555
"\\[ 9/4 March 16,1979 MEMORANDUM FOR: Saul Levine, Director, Office of Nuclear Regulatory Research Robert B. Minogue, Director, Office of Standa ds Development William J. Dircks Director, Office of Nuclear Material Safety and Safeguards THRU:
Karl R. Goller, Director, Division of Siting, Health and Safeguards Standards, SD Anthony R. Buhl, Director, Probabilistic Analysis Staff. RES FROM:
I. Craig Roberts, Assistant Director for Siting Standards, SD Michael C. Cullingford, Head, Fuel Cycle Section, PAS, RES
SUBJECT:
TRANSMITTAL OF THE NRC REVIEW GROUP REPORT ON THE U.S.
ENVIRONMENTAL PROTECTION AGENCY (EPA) RISK ASSESSMENT OF RADIOACTIVE WASTE ISOLATION IN DEEP GE0 LOGIC FORMATIONS This memorandum transmits the report of the NRC Review Group convened to review the EPA-sponsored work of Arthur D. Little, Inc. (ADL) on Risk Assessment of Radioactive Waste Isolation in Deep Geologic Fomations. EPA staff had prev 1:Jsly informed us (memo from Martin to Roberts, dated 11/30/78) that the ADL work wo'uld be an important part of the basis for their detailed HLW standard. The standard and its technical basis are of considerable importance to the NRC staff. Also, the analyses perfomed by ADL are similar to those that might be perfomed as a part of the licensing review of a repository.
Further, EPA requested that NRC staff review the draft ADL report. A critical scientific review was therefore performed.
The objectives of the review were:
(1) To identify any significant weaknesses in the ADL work and recommend further work to correct any deficiencies. This would assist NRC in the direction and management of research projects in similar areas, in addition to assisting EPA.
(2) To consider the capabilities and limitations of probabilistic risk assessment techniques with respect to waste isolation in deep geologic media.
(3) To examine the manner in which the ADL work was utilized to formulate the EPA draft standards and the degree to which the ADL results support those standards. The examination would provide insights into the use of probabilistic risk assessment in support of the formulation of standards for nuclear waste isolation.
7 9 041801 it b
2 Following are the major findings of the review group:
The attempt to use risk (expressed'as the product of probability and consequences) analysis to establish environmental standards is commen-dable and useful. However, supporting a standard with risk analysis does not necessarily mean that the standard has to be explicitly probabilistic.
The material reviewed provided inadequate technical support for the EPA standard.
The degree of conservatism in the resultant risk curves is not known since the ADL work did not include uncertainty analysis. Therefore it is impossible to know how realistic the "high" and " low" risk estimates actually are.
A rigorous sensitivity analysis and also a systematic examination of a comprehensive set of potential event chains were omitted from the ADL work. The risk magnitude and the specific radioisotopes which importantly contribute to the risk will depend upon the specific site, the site properties and the scenarios chosen for calculation.
Therefore the validity of the EPA conclusion that five specific radionuclides dominate the risk cannot be confimed.
Two further points should be noted:
This review was made possible by the active participation and cooperation of the EPA staff.
Probabilistic risk assessment is a relatively new and difficult field.
This is especially so when applied to waste isolation in geologic media, as compared to risk assessments involving facilities consisting largely of engineered systems.
It is not surprising therefore that deficiencies were identified by the Review Group.
Nevertheless it should be recognized that the ADL work represents a significant accomplishment. With this in mind, correction of the identified deficiencies would rthwhile.
AS I.CraigRo[rts,AssistantDirector for Sitids Standards Office of Standards Development W
a Michael C. C ngford, Head Fuel Cycle Section, PAS Office of Nuclear Regulatory Research
Enclosures:
1.
Subject report 2.
Memo fm Martin to Roberts, dtd 11/30/78 cc:
J. B. Martin R. Bernero R. Budnitz S
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