ML19345H120
| ML19345H120 | |
| Person / Time | |
|---|---|
| Issue date: | 03/11/1981 |
| From: | Bender M, Ray J, Seiss C, Siess C Advisory Committee on Reactor Safeguards |
| To: | Advisory Committee on Reactor Safeguards |
| References | |
| RTR-REGGD-01.136, RTR-REGGD-1.136, TASK-OS, TASK-RS-705-4, TASK-SC-705-4 ACRS-1824, NUDOCS 8104300586 | |
| Download: ML19345H120 (11) | |
Text
-
DATE ISSUED:
3/11/81 s
1 i-A gg,fg g v
d' Minuita vi
- Q ACRS SUBCOMMITTEE MEETING ON h< Y g L
l lm REGULATORY ACTIVITIES FEBRUARY 3, 1981
/
WASHINGTON, D.C.
The ACRS Subcommittee on Regulatory Activities held a meeting on February 3, Mr. Sam Duraiswamy was the 1981, at 1717 H Street, N.W., Washington, D.C.
A list of documents submitted Designated Federal Employee for the meeting.
to the Subcommittee is included in Attachment A.
ATTENDEES:
b C. P. Siess (Subcommittee Chairman), M. Bender, J.C
@j ACRS:
M. W. Carbon and D. A. Ward.
$$Ll)lj f h 1
U 2-ACRS R 2 S Jgg7 h q Consultant:
B. Johnson M*" h
\\
Principal NRC W. Morrison, W. Anderson, E. Wenzinger, A. Marin
\\p(g
. Rosa, Speakers:
ara, G. Knighton, R. Goel, G. Arndt, W. Haz Mu INTRODUCTORY STATEMENT BY THE SUBCOMMITTEE CHAIRMAfj, Dr. Siess, the Subcommittee Chainnan, convened the meeting at 8:45 a.m. and indicated that the purpose of the meeting was to review the following Regula-tory Guides:
Regulatory Guide (Task No. RS 705-4), " Lightning Protection for Nuclear 1.
Power Plants" (Post Comment).
Regulatory Guide (Task No. SC 705-4), " Ultrasonic Testing of Reactor Vessel 2.
Welds During Pre-Service and Inservice Examination" (Post Comment).
Regulatory Guide 1.136, Revision 2, " Materials, Construction and Testing 3.
of Concrete Containments" (Post Comment).
I Dr. Siess indicated that in addition to the above items, the Subcommittee would discuss also the adequacy of the NRC Staff's response (transmitted 23, 1981) through a letter from Mr. Arlotto to Mr. Fraley dated January 10, 1980 to ACRS comments and recommendations included in its November letter of concurrence in the regulatory positions of Regulatory Guide 1.97, Dr. Siess said that the Subcommittee had received written Revision 2.
comments from Duquesne Light Company on the Regulatory Guide entitled
" Lightning Protection for Nuclear Power Pla1ts"; it had received also written comments from Bechtel Power Corporation (San Francisco) on Regula-tory Guide 1.136, Revision 2 s104300ggg
Fcbruary 3,1981 Reg Act Mtg
- REGULATORY GUIDE (TA'K NO. RS 705 4). " LIGHTNING PROTECTION PLANTS" (POST COMMENT)
Prior to holding discussion with the NRC Staff on this Guide, Dr. Siess provided a brief preamble indicating that a previous version of this Guide was reviewed During by the Regulatory Activities Subcommittee at the May 3,1978 meeting.
that meeting, it was brought to the attention of the Subcommittee that there The Subcommittee were some differing technical opinions among the NRC Staff.
suggested that the NRC Staff try to resolve these differences and resubmit Another version of this Guide was considered by this Guide for further review.
At that the Regulatory Activhies Subcommittee at the January 3,1979 meeting.
meeting, the Subcommittee was informed by the Office of Standards Development (0SD) that all of the written comments based on dissenting technical opinions have been resolved with the exception of those from Mr. Rosa from the Office of the Nuclear Reactor Regulation (NRR). However, the 050 has reached a compromise with Mr. Rosa.that his view points will be included in this Guide as an " Alternate Regulatory Position" and public comments will be solicited on that alternate This Guide was issued for public comment in August 1979.
The approach.
The current version of this Guide reflects consideration of public comments.
NRC Staff requests ACRS concurrence in the main Regulatory Position of this Guide.
Indicating that he was informed just prior to the beginning of the meeting I
that NRR had withdrawn its concurrence in the Regulatory Positions of this Mr. Knighton re-Guide, Dr. Siess asked for the reasons for NRR withdrawl.
sponded that due to..ganizational changes the new management of the Divisio of Syi. ems Integration, which will be responsible for implementing the pro-visions of this Guide, did not have a chance to review the technical Therefore, after discussion, the NRR had decided adequacy of this Guide.
to withdraw its concurrence pending review by the new management.
In spite of NRR's withdrawl of its concurrence, since the Regulatory Positions in this Guide have been and still are the subject of " differing professional opinions," the Subcommittee decided to devote some time to a general dis-cussion of the technical differences and the need for this Guide.
v-
,----w
-.---m,.
,.w
,-+-.-,--,w.
February 3, 1981 R;g Act Mtg Pointing out that the " Implementation" section in the current version of this Guide states that the provisions of this Guide should be met by all operating plants, Dr. Siess commented that this backfitting requirement is a significant change from the previous versions of this Guide. The potential problemt and the costs associated with the backfitting of this Guide are not clear.
He suggested that a probabilistic risk analysis to justify the complete backfit of this Guide would be helpful.
Dr. Siess asked whether any probabilistic risk analysis has been done to determine the magnitude and contribution of risk associated with a potential Mr. Rosa responded that no such analysis has been done.
lightning surge.
In response to another question from Dr. Siess as to whether the operating experience shows that lightning surge is a significant contributor to risk, Mr. Marinos stated that based on his review of several licensing event reports related to lightning, he believes that lightning surges are significant con-tributors to risk. He pointed out also that few of the incidents even caused failures of certain redundant protection systems.
Dr. Siess commented that finding the things that can lead to failures of He believes that it is redundant systems is just one step in a fault tree.
necessary that someone should review the fault tree completely and decide whether those probable failures are significant contributors to risk and whether they will lead to failures of certain essential safety systems.
I, Mr. Rosa commented that he does not belien there is any correlation between the operating incidents involving lightning and some of the Regulatory Positions of this Guide. He does not believe that there are any data from operating experience that substantiate the requirement for lightning arrester discharge-current capacity of 120,000 amperes.
Mr. Ray commented that based on operating experience, he believes that a
- Further, direct lightning strike on a station equipment is a rare occurrence.
O
.q,e-.
- p. q -,mw,,-,-
-.m-~-y-
-,w-
~
w,
=, ---
--+
R;g Act Mtg Fcbruary 3,1981 since the present design practices use adequate shielding for essential components, a dire"t lightning strike on such components can be safely dis-This Guide seems to ignore the effectiveness of shielding by specify-coun+ed.
ing that station-type surge arresters should be designed to withstand a discharge-He does not believe that there is any data that current of 120,000 amperes.
120,000 can substantiate that the station-type surge arrester will discharge Further, surges resulting from a lightning stroke on a transmission amperes.
line will not carry the sams magnitude of current as the lightning stroke Therefore, he does not because they have multiple paths for dissipation.
believe that a surge propagating into the plant will warrant a surge arrester capacity of 120,000 amperes.
Mr. Bender commented that this Guide does not make it clear as to what we are concerned about mainly and how much protection is needed in addition If we are concerned to the protection provided by the existing designs.
about a station blackout incident due to lightning, it has to be made clear what this element of protection contribute'$ to the station blackout issue altogether.
Dr. Siess asked whether the lightning surges are expected to be capable of producing consequences different from or worse than a station blackout.
Mr. Marinos responded that he has not evaluated this issue and he believes that consideration should be given to this issue.
Dr. Siess commented that if the-station blackout incident due to lightning is considered to be a possible overriding effect, it might not be too difficult to perform a risk assessment to look at the contribution and probability of lightning stroke or surge to station blackout and the subse-He suggested that the appropriate office of the NRC quent consequences.
consider performing a probabilistic risk assessment study based on the station blackout type problem; he believes that such a study would be helpful in making decision on several issues associated with this Guide.
Mr. Johnson commented that since the essential components inside the plant have their own protective devices, he does not believe that by increasing the Cmn
February 3, 1981 R:;g Act Mtg discharge-current capability of the surge arresters will minimize or prevent the failures of these components.
Mr. Ray commented that lightning contributes to station blackout by tripping However, all breaker-the breakers and disconnecting the transmission lines.
Therefore, tripping incidents may not necessarily result in a station blackout.
he does not believe that a station blackout incident sl.ould be used as a predominant factor for the risk assessment study.
Surge protection applied at a high voltage switchyard or at a substation does not necessarily reduce If surges sufficiently to protect sensitive components inside the plant.
protecting a component from a lightning surge resulting from a lightning stroke on a transmission line is a concern, then it is necessary to concentrate on the development of an insulation coordination methodology and the development therefrom of protection devices for these components.
Mr. Bender commented he believes that a probabilistic risk assessment analysis should be performed to determine the level of risk reduction expected to be achieved by improving present protection capabilities in accordance with the guidelines provided in this Guide.
He criticized the NRC Staff's failure to seek supporting skills outside of the NRC organization to aid them in resolving the differing technical opinions. He believes it is inexcusable that the regulatory management has not brought some of its own consulting experts from outside to obtain a better spectrum of opinion on the issues associated with the lightning.
Dr. Siess stated that there are several questions that need to be answered:
Is there a risk at some level associated with lightning?
1.
2.
Will the provisions of this Guide reduce that risk?
Is the risk at such a level that a backfit is called for in 3.
this Guide?
He believes that some sort of risk assessment would be helpful to the NRC Staff and the ACRS to find answers to these questions and in arriving at a position on several of the issues associated with lightning.
After further discussion, the Subcommittee recommended strongly that NRR give consideration to perform a probabilistic risk assessment study to justify the
February 3,1981 Reg Act Mtg need for and the implementation of this Guide and resubmit it at a later date for further review.
If the NRC Staff cannot make such a study or feels that this Guide should be promulgated in the absense of a risk Mr. Knighton said assessment study, it should provide proper reasons.
that the NRR will give careful consideration to the Subcommittee's recom-mendation.
The ACRS has received a copy of the letter from Mr. Murley (Note:
(Director, Division of Safety Technology, NRR) to Mr. Arlotto (Director, Office of Engineering Standards, OSD) dated February 27, 1981 which indicates that the NRC Staff intends to initiate efforts to perform a risk assessment study as re-commended by the Regulatory Activities Subconrnittee to provide a stronger basis for 1,he need for the Regulatory Guide on Lightning Protectiori for Nuclear Power Plants. A copy of that letter is included as Attachment B).
REGULATORY GUIDE (TASK NO. SC-705-4), " ULTRASONIC TESTING OF REACTOR VESSEL WELDS DUP.ING PRE-SERVICE AND IN-SERVICE EXAMINATION" (POST CO l
Mr. Goel reviewed this Guide briefly, indicating that this Guide was developed as a result of NRR request to provide supplernentary guidance to the Ultrasonic Testing (UT) procedures specified in Section XI of the ASME Code,1977 edition.
A previous version of this Guide was reviewed by the Regulatory Activities i
Subcommittee during the October 4,1978 meeting and was issued for public The current version of this Guide reflects consideration comment in May 1979.
of public comments.
Dr. Siess pointed out that the Subcommittee had received comments from Dr. Bush l
(ACRS consultant) and Dr. Shewmon (ACRS Member) and these comm j
discussed during the course of the meeting.
Dr. Siess asked whether the office of NRR feels ihat tnis Guide is responsive Mr. Hazelton from NRR responded that he does not believe this to its needs.
Guide does everything NRR wants; but, it does several things that ought to be Further, NRR does not expect that this Guide will resolve all the problems done.
associated with UT inspection methods.
February 3,1981 Reg Act Mtg Dr. Carbon asked whether the implementation of the provisions of this Guide will improve actually the reliability of the existing UT inspection methods.
Mr. Hazelton responded that he believes it will. improve the reliability in the sense that it will help attain greater accuracy and consistency in flaw characterization.
The Subcommittee sought response from the NRC Staff to a comment by Dr. Bush in which he states that he is not convinced this Guide deals with the real problem of improved reliability in flaw detection. Mr. Hazelton responded that he believes some of the provisions (implicit) in this Guide will help improve the reliability of flaw detection. Mr. Goel said that there are several difficulties associated with enforcing certain advanced techniques, (that are expected to contribute to improved reliability) on t.he industry, because these techniques will cause an economic burden on the industry. He believes that the provisions of this Guide will provide flexibility to the industry to perfonn the job more economically; this Guide provides also improved guidance for detecting significant flaws. Mr. Anderson added that the NRC Staff has an ongoing contract with the Oak Ridge National Laboratory to study various techniques in this area and also to review the deficiencies in the ASME Code. Based on the results of that study, this Guide will be revised, and he believes that the revised Guide will contribute to improved relability in flaw detection. Mr. Geiske (NRC Staff's consultant) from Sandia Laboratories pointed out that the 20% DAC (Distance Amplitude Correc-tion) criterion specified in this Guide for sizing the flaws is a significant improvement over the current ASME Code practice which specifies 50% DAC for sizing. He believes that the implementation of this 20% DAC sizing criterion will improve the reliability of the flaw detection.
Mr. Bender commented that there should be a research program to complement the additional provisions of this Guide'and ensure that the implementation of these additional provisions will help detect significant flaws.
Dr. Shewmon also had a question (in writing) along the same line, as to whether the NRC Staff has any research planned or underway to establish the level of confidence with which the procedures suggested in this Guide will detect significant flaws.
February 3, 1981 R;g Act Mtg In response to tne above comments, Mr. Muscara stated that he believes certain work already done in the piping area would substantiate some of the provisions of this Guide. Further, they have an ongoing program at Battelle Northwest Laboratories to look at the reliability of inservice inspection of piping materials. This program has enough flexibility that it can be used to look at the issues associated with pressure vessels.
They plan to initiate work in the pressure vessel area sometime in FY 1982 following current programs relating to ultrasonic testing of piping.
The Subcommittee suggested some editorial changes, provided suggestions for improvement in certain areas of this Guide and indicated that it will re-commend this Guide to the full Committee during the February 5-7,1981 ACRS meeting for concurrence in the P.egulatory Positions.
REGULATORY GUIDE 1.136, REVISION 2, " MATERIALS, CONSTRUCTION, AND TESTING 0F CONCRETE CONTAINMENTS" (POST COM. TNT)
Mr. Graves provided a brief preamble to this Guide, indicating that it endorses, with certain e::ceptions, Articles CC-1000, -2000, -4000, -5000,
-6000, and -7000 of the " Code for Concrete Reactor Vessels and Containments" published jointly by the American Society of Mechanical Engineers (ASME Section III, Division 2,1980) and the American Concrete Institute (ACI Standard 359-80).
A previous version of this Guide was reviewed by the Regulatory Activities Subcommittee at the August 8,1979 meeting and was issued for public comment in November 1979.
The present version of this Guide reflects consideration of~public comments.
With regard to Regulatory Position C-12, Dr. Siess commented that it is not stated clearly. He suggested further that certain changes be made in Mr. Arndt stated f
this Guide to make it less prescriptive and more general.
that they will give consideration to these suggestions.
The Subcommittee discussed briefly the written comments provided by Bechtel Power Corporation.
In response to Bechtel's concern that several new Regulatory Positions had been added subsequent to the public comment period and the public
e c
g om -.
e e
Fcbruary 3,1981 Reg Act Mtg did not have a chance to comment upon these new positions, Mr. Arndt stated that these new Positions have been added to take care of the changes in the most recent issue of the ASME Code. Since the NRC Staff intends to revise this Guide periodically, he believes that the public can provide comments at any time for consideration during the next revision of this Guide.
The NRC Staff informed the Subcomittee that since they plan to update this Guide at intervals of about an year to incorporate, as appropriate, the changes in the Code which are made every six months, they would like to issue those revised versions without ACRS review unless they are considered to be controversial. The Subcommittee did not raise any objection to this proposal.
After further discussion, the Subcommittee indicated that it will recommend this Guide to the full Committee during the February 5-7, 1981 ACRS meeting for concurrence in the Regulatory Positions of this Guide.
DISCUSSION OF THE NRC STAFF'S RESPONSE TO ACRS COMMENTS ON REGULA GUIDE 1.97, REVISION 2, " INSTRUMENTATION FOR LIGHT-WATER-COOLED NUCLEAR POWER PLANTS TO ASSESS PLANT AND ENVIRONS CONDITIONS DURING AN AN ACCIDENT" The Subcommittee discussed the adequacy of the NRC Staff's response (transmitted through a letter from Mr. Arlotto to Mr. Fraley dated January 23, 1981) to ACRS comments on Regulatory Guide 1.97, Revision 2 included in the Committee's letter dated November 10, 1980.
After dis-cussion, the Subcommittee made the following comments:
The NRC Staff's response to the ACRS comment related to BWR incore 1.
thennocouples is acceptable.
The NRC Staff's action is not responsive to ACRS recommendation on
?.
the environs radiation monitoring requirement.
The NRC Staff's effort in resolving the ACRS comment on the imple-3.
mentation dates of the requirements of Regulatory Guide 1.97, Revision 2 is inadequate. The Subcomittee expressed concern, indicating that in view of the fact that NUREG-0696 which is intended
February 3, 1981 Reg Act Mtg to provide guidance o.' the emergency operational facilities has been delayed, the implementation dates for Regulatory Guide 1.97, Re-vision 2 are too early.
The Subcommittee indicated that with the approval of the full Committee, a letter will be sent to the NRC Staff to inform them of ACRS views on this issue Dr. Siess thanked all pRrticipants and adjourned the meeting at 1:15 p.m.
i 4
/
d i
Reg Act 2/3/81 Mtg APPENDIX A LIST OF DOCUMENTS SUBMITTED TO THE SUBCOMMITTEE Regulatory Guide (Task No. RS 705-4), " Lightning Protection for Nuclear 1.
Power Plants" (Post Comment).
Regulatory Guide (Task No. SC 705-4), " Ultrasonic Testing of Reactor Vessel 2.
Welds During Pre-Service and Inservice Examiantion" (Post Comment).
Regulatory Guide 1.136, Revision 2, " Materials, Construction and Testing 3.
of Concrete Containments" (Post Comment).
t
s SP U 8 */ 1331 2 F:.1 2 13 I;E!! ORA!! Dull FOR:
Guy Arlotto Director
.. m.
7 Division of Engineering Standards
'SJ_ l.C.L. M M;,E'.i Office of Standards Developaent
. :,; - u FRO:.;:
Thonas E. liurley, Director Division of Safety Technology Office of ;uclear Rcactor Regulation DRAFT REGULATORY GUIDE Of: LIGHTNING PROTECTI0f SUCJECT:
FOR :'UCLEAR POWER PLA!;TS, RS 705-4 Dased on further review and discussions with the ACP.S Subcomittee on Regulctory Activities on February 3,1981, ue request that the subject guide be placed in a hold status pending further evaluation along the The subcomittee suggested lines suggested by the ACRS subcorr.iittee.
that prior to further review by the ACRS a risk assess.icnt should be attenpted to provide c stronger basis fo support a regulatory position and an inpler.entation position. The subcorr.ittee also succested utilization of a third opinion to further evaluate the issues in contention raised in the presentation of the two proposed regulatory It is our intent to initiate efforts in response to the positions.
ACRS suggestions, and uc will send you our plans and schedules by Ik.rch 15,1931.
Msinal sic: ed b;s
% :nsE.sy73,g,
Thomas E. I;urley, Director Divi;,ien of Safety Technol: gy Office of I uclear Reactor Regulation cc:
D. Ross P. Check F. Rosa E. lienzinger
[g 0$
A. Mcrins U
watIUgH nL F
DISTRIBUTION Fl x d 7 CENTRAL FILES FSCHROEDER 4
RSCB READING FILE TMURLEY A 77dc H M e NT" 3 fIc TERA AEOD f6*
01E s A RS RSILVER GWKNIGHg0N c"'c c i ST.185.CR...
k......D.$ T., fD....
. p.S'i g.... _.. _.__....~.._._.
,_.._.~..- -....
.E$chroeder.....Tdu$rl ey,.......
.......... - ~ ~.. -.... ~ ~ -
.! 2....h.. 1N'k i h on..
RSi1.ver.:clc..
...Sf*...........'.*...........................--.-.....-.~A 1
c"Q.2L25LB1
.ac e ow de~io somacu o:40 OFFICIAL RECORD COPY
_