ML25196A138
| ML25196A138 | |
| Person / Time | |
|---|---|
| Issue date: | 08/25/1978 |
| From: | Lawroski S Advisory Committee on Reactor Safeguards |
| To: | Hendrie J NRC/Chairman |
| References | |
| Download: ML25196A138 (1) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION ADVISORY COMMITTEE ON REACTOR SAFEGUARDS WASHINGTON. D. C. 20555 August 25, 1978 Honorable Joseph M. Hendrie Olairman
- o. s. Nuclear Regulatory camrl.ssion washington, DC 20555 SOBJfx:'1':
Ml\Y-Am.JST, 1978
Dear Dr. Henclr ie:
'ibis is a brief report of ACRS activities during May, JlD'le, July, and August 1978. Selected topics in this report will be discussed during the next joint NRC-ACRS meeting.
Proposed Use of CRAC Code in Site Comparisons
'!be Caimittee has considered the NRC Staff's proposed use of the con-sequence model (the "CRAc* Code), which was developed for the Reactor safety Study (WASH-1400), for evaluating environmental impacts of al-ternatives to sites with relatively high population density.
Studies to date have shown that the CRAC Code can provide additional umerstanding of the public health impacts of accidents exceeding the limits of 10 CFR 100. However, there are many factors influencing the application of the code that have an important bearing on the computa-tional results but which the code does not cddress cdequately. 'lhese include regional meteorology (particularly for coastal and river valley sites), plume geometry, a."ld effluent particle size distribution.
In addition, the code does not address the behavior of radionuclides within containment prior to release. Also, the probability of various release magnitudes remains a factor having considerable lU'lcertainty.
For this reason, the ACRS reconmends caution in the use of the code as a determining basis for judgment in alternative site evaluations.
Nevertheless, the CRAC Code is one of the more useful methods currently available for evaluating environmental impacts of alternative sites, and efforts should be continued to develop improved input data for the Code.
2815
Honorable Joseph August 25, 1978 Dynamic Loading Combinations
'lhe Committee has attempted on several recent occasions, including its 218th meeting, June 1-2, 1978, to encourage the Office of Nuclear Reactor Regulation to reconsider the rationale for establishing design basis loadings and loading combinations in performing safety analy$es.
The ACRS recommends that such a reevaluation be undertaken as soon as possible.
NRC Staff Response to ACRS Recommendations During its April 1978 meeting the Committee heard a report regarding action taken in connection with ACRS recommendations in its January 14, 1977 report to you on operation of Davis-Besse Unit 1. Of the nine specific recommendations made by the Committee, action had been recently initiated on four and only preliminary work had been started on the other five.
On March 12, 1976, the Committee recommended pranpt implementation of Reactor Pump Trip (RPI') for BWRs.
letters were sent to BWR licensees in May of 1978 by the NRC Staff specifying criteria for RPI' design.
In order to obtain earlier responses to Canmittee recanmendations, a follow-up system has been instituted which involves surranarizing Canmit-tee requests within 6 nonths and a formal response by the Staff there-after.
Reply to Congressman Udall
'l'1e Committee has forwarded a reply to Congressman Udall's inquiry about the need for a statutory board to review reactor safety matters, patterned after the National Transportation Safety Boar.a.
In its reply, the Committee stated that it did not believe that such a board was necessary, based on the assigned responsibilities and current activi-ties of the NRC and ACRS and on the history of operation of commercial nuclear power plants.
Nuclear Plant Reliability Data System (NPRDS)
The Committee has considered a proposal to make a reliability data collection system mandatory for all licensees.
In a memorandum to the Executive Director for Operations dated July 12, 1978, the Canmit-tee concluded that the existing system was providing data at a reason-able rate, but suggested also that the system could be improved by analyses of the internal consistency, usefulness, and reasonableness of the data already on hand.
'!he Committee did not recanmend that NPRDS reporting be made mandatory.
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Honorable Joseph M. Herx:Jrie August 25, 1978 Implementation of RG 1.97, Revision 1, "Instrumentation to Follow the Course of an Accident" The Corranittee has for some time been urging improvements in instnnnen-tation to follow the course of accidents.
In August 1977, Revision 1 to RG 1.97 was published but no firm schedule for its implementation has as yet been established. '!he NRC Staff is -working with selected licensees to develop approaches to implement the Guide. 'Ihe Ccmrnittee will continue to monitor the implementation of this Guide.
Anticipated Transients Without Scram (ATWS)
The Connnittee's A'IWS Subcorrmittee is proceeding with its review of the recently published NUREG-0460 - "Anticipated Transients Without Scram."
The Connnittee hopes to reach a conclusion in this area by the end of 1978.
Generic Items The Corranittee is planning the customary semiannual reevaluation of its list of l.D'lresolved generic items, and is planning to initiate a de-tailed review of the implementation of those items that are considered to have been resolved generically.
IOCA-ECCS Research Programs The RES Staff has proposed that current IOCA-ECCS research programs be carried to completion, but that no new large IOCA-ECCS test facilities (e.g., the EBTF, Multi-Purpose Test Facility, etc.) be constructed.
They have also recommended that the cooperative program with Japan, France and the Federal Republic of Germany be expanded.
'Ihe ACRS con-curs in these suggestions.
Future Schedule No Projects Scheduled 222nd ACRS MEETING OC'IOBER 5-7, 1978 2817
Honorable Joseph August 25, 1978 223rd ACRS MEETING IDVEMBER 2-4, 1978 Zinvner (OL}
~
Safety Evaluation Report ACRS Subcommittee Meeting
- . *. ACRS Report BOPPSAR/BSAR-205 (PDA)
CNRR Safety Evaluation.
ACRS Subcommittee Meeting ACRS Report GETR (Special Review)
CNRR Safety Evaluation Report ACRS Subcommittee Meeting ACRS Report
- To be scheduled 9/1/78 11/9/78 10/2/78 11/9/78 11/9/78 Sincerely yours,
..,~
Stephen Lawroski Olairman 2818