ML16340B452

Responds to Request Re Position on Safety Implications of Control Systems & Plant Dynamics & Relevance to TMI-1 ASLB Hearing.Disagrees W/Assumption That Safety Sys Will Mitigate Control Sys Failures at Any Power

ML16340B452
Person / Time
Site:	Diablo Canyon, Crane
Issue date:	10/10/1980
From:	Basdekas D NRC OFFICE OF NUCLEAR REGULATORY RESEARCH (RES)
To:	Tourtellotte J NRC OFFICE OF THE EXECUTIVE LEGAL DIRECTOR (OELD)
Shared Package
ML16340B451	List: ML16340B450 ML16340B452 ML16341C389
References
NUDOCS 8102260678
Download: ML16340B452 (8)

Text

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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, O. C. 20555 October 10, 1980 r

MEMORANDUM FOR:

James R. Tourtellotte, Esq.

Assistant Chief Hearing Counsel, ELD FROM:

SUBJECT:

Demetrios L. Basdekas Reactor Safety Engineer, RSR,RES SAFETY IMPLICATIONS OF CONTROL SYSTEMS AND PLANT DYNAMICS,AND THEIR RELEYANCE TO THE'TMI-1 ASLB HEARING This is in,response to your request of this morning for a brief statement of my position on the subject matter.

The issue of the effects on safety of the control systems, which have been classified and treated as non-safety

systems, has )ep discussed within and outside the Commission over a long period of time~

s Even though it has been treated as a generic issue, it applies directly to the TMI-l, as it will be evident from my discussion of the problem in. references 1 and 2.

The record clearly sho~s that for all intents and purposes of the provisions of the NRC Manual Chapter 4125, I hav'e discussed it with.NRR management as well as OCM repeatedly.

I have also taken my position on this matter to the ACRS and the Congress, and hence the public record.

Thus the entire cognizant NRC management structure has had the repeated opportunity to hear, comment and act on my position and recommendations.

I disagree with the Staff's position, which has been largely unchanged since December 1976.

The basic d',sagreement stems from the assumption made by the

Staff, and still held despite the TMI-2 accident, that "safety systems will mitigate control system failures at any power".

The somewhat diffently worded Staff position contained in testimony prepared for the TMI-1 ASLB hearing reflects the same basic position, and attendant conclusion that no licensing action is warranted.

In order to avoid repetition, and in view of the time constraints in responding to'your request of this morning, I am enclosing copies of references 1 and 2, which I believe describe and justify my position on this important matter, as well as provide a partial listing of applicable additional references.

The views I express here are personal and do riot necessarily reflect those of my present management chain.

If I can be of.further assistance please let me know.

.'Sl 02260///'it::

Demetrios L.

asdekas instrumentation, Control t'ower Sl, stem Rr~nch

"-<>.~E<

James R. Tourtellotte, Esq.

October 10, 1980 References 1.

Memorandum to Commissioner John F. Ahearne from Demetrios L. Basdekas dated'September 4,

1979 with enclosures,

2. Letter to Congressman Morris K. Udall from Demetrios L. Basdekas dated May 28, 1980.

t

'E

Comnissioner John F. Ahearne w3 SEP 4 mS operating experience (particularly after the TMI accident, e.g.

in Crystal River, Unit 3 on August 16-17, see PH0-79-341, 341A, 3418) support my view that such an action would be prudent, however painful or even.

unpopular.

I urge that the Comnission give such action serious and prompt consideration.

I hope this discussion is basically responsive to your request.

If you have any questions I will be glad to'discuss them with you at your convenience.

The views I express in this memorandum are my own and do not necessarily represent those of the Office of Nuclear Regulatory Research.

They are

based, in part, on discussions I had with representatives of BIKM and four utilities, the NRR consultants at Oak Ridge National Laboratory, and the NRC project manager of Task A-17, Unresolved Safety Issues.

Enclosures:

As stated

~~ ~ 8~~.

Demetrios L. Basdekas Experimental Fast Reactor Safety Research Branch

References:

%of 1.

Memorandum from D. L. Basdekas to B.

C. Rusche, November<19,1979 and December 20, 1979.

2.

ACRS transcripts of December 3-9, 1976, and Februaryi.-12, 1977.

3.

HUREG-013S, -0153, Safety Issues Hos.

6 and 22.

4.

Note from D. L. Basdekas to the Cemissioners, May 25, 1979.

5.

Memorandum from D. L. Basdekas to M. M. Carbon, June 5, 1979.

(Enclosed) 6.

Record of Hearing, United States

.Senate, Comnittee on Government

~

Operations, December 13, 1976.

cc:

Chairman Hendrie Cumnissioner Gi linsky Comnissioner Kennedy

'omnissioner Bradford L. Y. Gossick, EDO M. M. Carbon, ACRS H. R.'Denton, NRR S. Levine, RES R. Minogue, SD

A CON'ARAIIK L)ST)AC OF SAfETT CGttCEAJIS )Ef02E AND ACTIONS AFIEA THE TH) ACC)OEHT I)ay Tl, )979" REV ~t 3O, 1979 SAIE)V CONCLRNS EZPRESSIO OV O. L. OA&IXAS~ A)AC)OR SAIE)V LHGINIIR,

u. S.

RUCLEAR RKCULATORY CONy)ISSIOH ~ % NOVIIR~ER IO 1 19 ~ 1976 AHO OECEHB'EA 2oh 1916 ~ SAIE)Y ISSUE ho 22 ~ HUR'EC 0153 RLCO kW)AIIONS OT TllE NRC REtsULA)ORY SlAfF IKLUO)hC A CLÃgi)I~

HAOE BY OABCOCX Ahto )IIICOX COP~uiv, OESIGNIR Of )HdsEE HILE ISULAO (IÃl)

UNII 2 IQCLEAR PIKER PLANT SUBSEQKHT TO M, ACCIOQII AT THI SAFETY IIIPLICATIONS Of CONIROI SYS)lH FAILURES A%

(~WHIG ~

"the effects of control systcu failures or, sooetlues, non-faulted operation on satcty are not being systceatfcally rcrlchdcd.

I bc) Icve that their ~ttcCtS on safety and plant availability should receive the proper a'Ltcntlon.

The first step sou)d bc to have the applicants pcrfovu a Failure Node and Effects Analysis (fHEA) for norual operation, and ia conjunction ulth postulated accidents and other otf-nocaa) events."

<<In cvaluat.lng plant safety. the affects of control system aa)functions should be reviewed as inltlatlng cvcnts for anticipated transients and also as failures that. cou'id occur concurrently or subsequent to postu)atcd anticipated events (initiated by a difterent ualfunctlon) or postulated accldentsn<<

".. ~ one has to consider that design features to litigate thc consequences of such events are not established; and Lhcretare, those provided for postulated snd anslyssd accidcncs nsy nnt hn snfclclsns ~ Shns, In nssama,~hevln an v

rotcctcd scrics of events.

On a related'ssue ou reliability and risk assessucnt:

~ c~a node failures and events that Day rcsu)t in such fal)ures, along ulth huean factors, are expected to contribute uast significantly to the unavallabl)lty af the shutdoun system...

~

(Frau Olscussion of issue Ho. BB, GREC-0) 3S)

On Atyri) 76, )979. a)<<ost a +anth after the THI accident The )sabcock aran QI)cox Coepany, deslgrcr af the IHI Hvc)ear Povcr P)ant ~ mde the to))ovid cdy<<d<<ltdhent Lo IQC by letter tron J.

H. l4cNI))an, Vlcc-President Ikc)car Division to Il. A. Ocnton, Oircctor, Office of Huc)aar Reactor Rc)N)ation<<

u.S.H. A. Cn I

Subject:

integrated Central Systca This )ettcr documents the caasltxhcnt of Nabcock and MI)sox te undertake a re 1 lab lIlty analysis of the integrated Control Systca (ICS) which ulll Include a fai)ura aodc and effects ana)ysls.<<

this ana)ysis uil) identify sources of trans)erato, IF any, Inltiatcd by the ICS and deva)op rccodvvcndcd deslgyv Iwroveaents erich aay bc necessary to reduce Lhc frequency of these transients.

ln addition, means ui)) bo developed far decem@) fng of thc auxl) iary feed ster control of stoma generator vatcr level free the ICS.

This aoaiticat.ian u))) provide contra) of faabetar under edvcrgcncy conditions Independcnl of the ICS.

The scope of the reliability analysis ad schedu1a for both tho analysis and dere)oixxcnt at Independent focdhdatcr central uli) be provided uithln Ql hours.<<

On Ity l6,'1979 th kaC Regulatory Staff Issued rcport ltUREC-0560 entitIcd Staff Rr rt on the Ccncrtc Assessecnt of fccdhvater Transients in Pressurized Q~

a oc a

cox an The report rccoeehcnds that:

<<n coun er ng s

s aripavents n

caber 1976 the HRC Rcgu)atary Staff aa lnta Ined:

<<Although analyses have not been pcrtorucd for these postulated sequences of events, Lhc slatf believes that the consequences sou)d bc acccpLabic, auf auch less severe than those calcu) ~Led for.cestui a to4 accidents."

In a Rcport ta thc Congress, IAIREI'38, Aprli 12, 1978, The Office of Huc)car'Regulatory Research of NRC, In Justify!ad) lts position that no further research effort uas accdcd aa Improved Plant Controls

~ reported:

<<tt is believed that only a saba)l reduction In risk could rcsu)t.fnw Inprovcahcnts la plant controls

~ and that

~ ~ ~.the Industvy say explore this area voluntarily.

"Al) classes of operating p)ants Fhou)d be reanalyzed using failure rhode and effects analysis ta Identify realistic plant Interactions resulting froa faI)uras In non-safety systcas, safety systcsa and operator actions d Iag transicrcts and accidents.

lhe role of contra) systcas ir all plants, and their signific-ancee Lo safety, should be reevaluated Sy'XRC and the vcndurs.

The evaluations should be pcrtomcd by thc industry ulth guide-lines developed by the NRC.

Consideratlbn should be given to estab) lshing criteria regarding the rate at uhich transients challenge Lhe plant safety systcas.

Such transients should Include (a) those initiated Ly control failure p)us (b) those Initiated outside Lhc control systca that are aot succassfully alt)gated by Lhe coatrol systcxL,<<

port AM vas s

ttc to oa August )7<<)%79