ML19343D242
| ML19343D242 | |
| Person / Time | |
|---|---|
| Issue date: | 04/09/1981 |
| From: | Advisory Committee on Reactor Safeguards |
| To: | Advisory Committee on Reactor Safeguards |
| References | |
| ACRS-1819, NUDOCS 8105040032 | |
| Download: ML19343D242 (8) | |
Text
Aus Isly DATE ISSUED:
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ELECTRICAL 5E SUBCOMMITTEE JANUARY 23, 1981 WASHINGTON, D.C.
The ACRS Subcommittee on Electrical Systems held a meeting on January 23, 1981 at 1717 H Street, N.W., Washington, D.C.
The purpose of this meeting was to discuss the safety implications of control system failures and to undertake a response to a request from Congressman Udall for a Subcommittee review of NRC rationale upon which its judgment relating control system f ailures were Notice of this meeting was published in the Federal Register on founded.
A list January 6,1981.
A copy of this notice is enclosed as Attachment A.
of attendees is included as Attachment B and the schedule for this meeting is included as Attar.hment C.
No written statements or requests for time to make oral statemen'ts were received from members of the public.
The principal attendees at this meeting were as follows:
W. Kerr, Chairman J. Ebersole, Subcommittee member yilm W. Mathis, Subcommittee member e
,D J. Ray, Subcommittee member R. Savio, ACRS Staff h /lp 77 W. Lipirski, ACRS Consultant g2S g0/A Ag 1
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E. Epler, ACRS Consultant P
F. Rosa, NRC Staff
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o E. Rossi. NRC Staff W. Morris, NRC Staff D. Basdekas, NRC Staff K. Kniel, NRC Staff P. Norian, NRC Staff J. Stolz, NRC Staff The meeting was begun at 8:40 am on January 23, 1981 and was adjourned on the The entire meeting was held in open session.
same day.
INTRODUCTION Dr. Kerr opened the taeeting with a summary of the purpose of the meeting and discussed the approach which could be taken in addressing the question of the l
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- f. January 23, 1981
.Electrical Systems of the safety implications of control system failures.
It was generally agreed that some system improvements needed to be made.
Improved safety control system separation, improved design criteria for control systems, the use of very high reliability auxiliary heat removal systems, and the identifi-cation of an improved set of limiting control system transients were suggested items deserving consideration.
DISCUSSIONS WITH THE NRC STAFF _
Mr. F. Rosa and Mr. E. Rossi, summarized the regulatory approach which had It was required that reliable safety systems be been used in pre-TMI reviews.
provided that would maintain critical reactor parameters within acceptable The effectiveness of these systems was established by deterministic bounds.
The guidelines under which these analyses were conducted required analysis.
that no credit be taken for any benefit achieved by action of a control system from operator intervention.
The adversa effects of control systems on or operator action and challenges to the reactor protection system were consid-There was no systematic analysis of ered for a specific range of transients.
The design basis single failure induced multiple control system failures.
In events were nontechanistic in that specific failures were postulated.
no credit was taken for operator action within 10 minutes of the
- general, initiation of the transient.
The requirements The design requirements for safety systems were discussed.
have been directed toward insuring that the safety system would not b'e de-Some common mode feated within the framework of a single failure analysis.
f ailures, such as fires and earthquakes, have been considered in the design
, January 23, 1981
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' Electrical Systems i
The frequency at which plant systems, such as control systems fail, basis.
has generally not been considered.
Standards for separation and single No similar failure criteria for electrical systems are described in IEEE-297.
industry standard exists for machanical, air, or hydraulic systems.
This approach differs from that used by the Canadians.
The regulatory practice used there sets definite limits for the frequency for control system failures which challenge a safety system.
I The potential of high energy line breaks for causing multiple control system Scenarios were f ailurs has been recently been considered by the NRC Staff.
postulated for. which high energy line breaks could cause multiple control
- It system failures which would increa'se the consequences of the transient.
was suggested that there may be similar events which have not yet been ana-Damage to control air line' manifolds and the possibility of a scenario lyzed.
involving damage to BWR control rod hydraulic drive lines were given as examples.
A Failure Modes and Effects Analysis (FMEA) has been performed for the B&W The NRC Staff does not now have any plans for Integrated Control System.
There are differ-requiring that the other vendors perform similar analyses.
ences of opinion among NRC Staff as to whether the benefits of such an analy-sis justify the resources required. No specific events were identified in the Some of the analysis which could lead to unacceptable consequences.
B&W participating utilities did, however, modify plant procedures to include The NRC Staff additional actions for dealing with control system failures.
did not perform an independent review of the methods used to produce these submittals but insted relied on the information provided.
b
. January 23, 1981 Electrical Systems for an ACRS review of the NRC Staff's position on the safety implications of control systems was discussed.
The matter has been identified as an Unre-solved Safety Issue (USI) by the NRC Staff.
A Task Manager is to be assigned to this project in the very near future and a draft of the action plan is to be developed within three montM..
The Subcommittee expects to respond to Congressman Udall's request in about six months.
FOR ADDITIONAL DETAILS, A COMPLETE TRANSCRIPT OF THE MEETING IS AVAIL-ABLE FRCM THE NRC PUBLIC DOCUMENT ROOM,1717 H STREET, N.W., WASHINGTON, NOTE:
20555, OR AT COST FROM ALDERSON REPORTING COMPANY, INC., 400 VIRGINIA AV S.W., WASHINGTON, D.C. 20024.
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Page titled, " Safety Implications of Control Systems " supplied by 1.
the NRC 2.
Internal NRC memos (a) Dec 13, 1980, S. Hanauer to H. Denton (b) Dec 4,1980, D. Ross to H. Denton w/ attach Internal ACRS memo, R. Savio to W. Kerr et al 3.
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Draft ACRS lte, 11/23/80, W. Kerr to J. Ahearne O
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-_a4ral Register / Vd. 46. N L'
Deted: December 30.1 set Advtoory Committee en Reactor.
A Sefeguarde; Sut> committee on g
. Desed December 17, tsad.
Samuel I. Oilk.
Emergency Core Coonne Spotoma; t
pens A. lemeph.
Secretary ofthe Caounission.
pair Northem Af:nono Islands Conunission ye on oi.mo rw+ei ses g Meeting airederoll.ows.
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ne ACRS Subcommittee on re o= si-w rad $+a. ** =I Emertem Ne Coofine sva'= will 8
16 to a m?etmg on lenuarv t4 and 1_5.
susso coot asie **de Addsory Committee on Reactor 1981,in Albuquerque. M_1 The Safeguards;Sut> committee on AC/DC Subcommatee win meet at a:30 a.m. at Power Systems Renabuity; Meeting the Albuquerque Inn (Phone: 505-247-
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llVCt. EAR REGut.ATORY COMMISSION De ACRS Subcommittee on theg.
3344). 2nd at Marquette Street. N.W.
DC Power 9vetem Rai!M'r will hold Albuquerque.NM.no Subcommittee g
Advisory Committee on Reactor a muung at,gg,g.s on lanuarv 21 will discuss the !.OCA/ECCS advanced I
code development and experimental
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saf;gu rds Subcommittee on 1981 in Room tm 1717 H street. N.W-Electrical Power Systems; Meeting Washir.ston, DC to discuss the expected programs, and the experimental program h.,
F ne ACRS Subcommittee on the NRC report on DC power systems at Sandia on Steam Explosions.
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te* p_,wer Svstems wi!I hold a reliability and the NRC plans for future In eccordance with the procedures g.O outlined in the Federal Register on work.
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inung a 6 m 4 m. on lanuary n 19e1 In accordance with the procedures Octs,ber 7.1980. (45 FR 86535). oral or */
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b Room i
- u. t,1, H Street. N.W.,
outlined in the Federal Register on written statements may be presented by
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members of the public, recordings Wtil r!ashington.DC to discuss matters October 7.1980 (45 FR 88535), oral or written statements may be presented by be permitted only dudag eose portions \\ 8 l
' f 'solating to instrument and controsystem fattures which could initiate or members of the public, recordings will l
of the meeting when a transcript is beingP exacerbate reactor accidents.
be permitted only dunng those po-tions kept. and questions amay be asked only *h. Ib In accordance with the procedures of the meeting when a transcript la being by members of the Suhea==fttee.Its outlin2d in the Federal Register on kept, and questions may be asked only consultants, and Staff. Persons desiring /
to make oral statements should notify OctobIt 7.1980. (45 FR 66535). oral or by members of the Subconuzittee.its writt:n statements may be presented by consultants, and Staff. Persons desiring the Designated Federal Employee se far C' k
e
. sambers of the pubhc recordings will to make oral statements should notify in advance as practicable so that w.
appropriate arrangements can be made.. -
Y be permitted only during those portions the Designated Federal Employee as far of ths meeting when a transcript is being in advance as practicable so that to aHow the necewary time dudag ee J
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hept. and questions may be asked only approptiste arrangements can be made n.eeting for such statementa.
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N by mImbers of the Subcommittee.ita to allow the necessary time during the ne entire meeting will be open to s.
I consultants. and Staff. Persons desiring meeting for such statements.
public attendanca.
t2 make oral statements should notify
%e entire meeting will be open to ne agenda for sablect meeting shaU thi Designated Feders! Employee as far Public attendance.
be as follows:
in cdvance as practicable so that nea nda for subject meeting shall g
appropriate arrangements can be made as ows.
to all:w the necessary time during the AJO oJn. antillhe concharios o[&usmew Thunday./onoory2r, fast mesting for such statements.
&JO o.m. untillhe conclusion of business.
each day.
During the taltial portion of the moettag.
Th2 entire meeting willbe open to Dunna th initial portion of b sweting.
ee Subcomminw. along wie any Cts j
public attendance.
ee Subcomminw. alms wie any d us consultanta who may be present, will ne agenda for subject meeting shall consultants who may be present will 9 as gows..
exchange preliminary views regarding exchange prolinunary views regardmg
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i matters to be considered dunas the balance snauere to be considered during the belena af the muting Drday./onuary21 farf of h anting.
The S.bcommittee wlU then hear
AJO o.m. until(Ae concharios of business.
The Subcommittee will then bear pruentations by and hold discusions with i
Dunns &* u..bal Pomon d the mutmg*
prnentations ty end hold discussions with the Subcommittu, along with any ofits representatives of the NRC Staff, their reprnentatives of the NRC Staff. their n
consultants. and other internted pereces i
t consultants, and other interested persons l
consultents who may be present, wd!
regarding this review.
eschenae preliminary views regarding regardmg this review.
Further Information about topics to be mittses to be considered during the belance Further information regarding topica discussed whether the meeting has r&f the meeting.
to be discussed, whether the meeting been cancelled or rescheduled. the Tha Subcomminee wiD then hear has been canceUed or rescheduled, the prnentations by and hold discussions with Chairman's ruling on requests for the Chairman's ruling on requests for the representatises of the NRC Staff, their
' opportunity to present oral statements opportunity to present oral statements consultants and otherintested persons and the time allotted therefor can be and the time allotted therefor can be reg:rdmg this review.
obtained by a prepold telephone caU to obtained by a prepaid telephone caU to the cognizant Designated Federal Further information regarding topics the cognizant Designated Federal.
13 he discussed, whether the meeting Employee.Dr.Richardh(telephone Employee.Dr. Andrew L Bates--
O'. an"d 5 00 p.m EST.
"U a.m zirman ruli g on ues f th 5:00 p.m EST.
Deted: December 30.1 sea cpportunity to present oral statements Dated: December 30. teen snd the time allotted therefor can be samuell.Onik.
Secretary of the Commission.
Samuel I. ciilk.
cbt'ained by a prepaid telephone call to Secretary ofthe Commise/ art the cognizanI Designated Federal punn.n-amare.a.m; ens t Employee. D* trW~4 e n (telephone yu on. m-an re smo t a
salass coot reemeus
= ma coca rise.aus 202/634-321 between 8.15 a.m. and l.
5:00 p.m EST.
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SCHEDULE FOR JANUARY 23, 1981 MEETING OF THE ELECTRICAL SYSTEMS SUBCOMMITTEE 8:30 - 8:45 am EXECUTIVE SESSION c
Discussions with the NRC Staff on the Safety 8:45 - COB Iglications of Control Systems O
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