ML19322C681
| ML19322C681 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 11/07/1977 |
| From: | Muller R Advisory Committee on Reactor Safeguards |
| To: | Stahle C Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML19322C677 | List: |
| References | |
| TASK-TF, TASK-TMR 7712107, NUDOCS 8001200005 | |
| Download: ML19322C681 (12) | |
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- UNITED *,TATES
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NUCLEAR REGULA fCRY CC.'.i.'.11::.SICN Q
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ADVISORY CC!.i?.it TTEE CN REACTOR SATEr.UAnOS
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!!ovember 7, 1977 Carl Stahle.
LPM Pebble Springs fluclear Plant l
SUBJECT:
ACRS QUESTI0ls RE PE3BLE SPRIllGS REVIE'l i
Attaghed are questions raised by an ACRS member, to which the Pebble e
Springs Subce:anittee would like written responses prior to ACRS full Cc.T.mittee review of that project.
. j At this mcment it is not planned to schedule another Subccrr.ittee meeting prior to full Ccmm ttee review, therefore it is requested that responses be provided as early as pcssible.
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.i Ragnwald Muller Senior Staff Engineer ATTACHMEitT Questions raised by ACRS Member l
cc:
R. Boyd L. Crocker i
S. Varga T.H. Cox (2 ccpies)
J.C. McKinley M.'!. Libarkin J.C. Ebersole S.H. Bush M.S. Plesset H.S. Isbin D. Okrent 4
g 8001200006
d TCPICS CJ PET:Jf.E SP91::G3 (related to d!!AR-205) 1.
Provida the intrepretation uccd in design, ot GDC 19 and Rcq. Guide 1.75 (IEEE 334).
The less conservative interpretation of GCC 19 coes not allow ccanon damage in control rcom.
N 1.75 permits convergence o,f total plant shutdcwn capability down to spacing masured in inches (witn scme form of panel er plate type of tarrier) to a few feet of open space.
More conservative intertretatica of GCC 19 would re-s quire (as IAEA dces) thac safe shutdown can 'ce accom-plishc<1 if the centrol rcca (and prest =acly any other given safety " space") is subject to cemen du.2ge within that space.
t Use of the less ccnservative interpretatica of tnese
' criteria results as a "sof t" cesign witn extrecely heavy require:mnts en
- administrative control".
If the design is *sef t" descric.c the corre.!gendingly "hard" administrative centrols.
i I
2.
Clarify the raticnale u. sed for Iceaticn of irraight secticns of main stext and feediater lic.cs in cesgcc to rotential dr.1ga to safety cquip 2nt.
Is it asctur,2d 1
that such pipe necticas are infallible?
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3.
Does the desv;n accoranodate pcten ial for inacvertent ficcding frcm vessel and piping failures witnin
" safety" structures or in sucn areas where safe-shutdown equignent is locateo?
t I
4.
hhat is stress-level and maximum local defccmation in es and tub sheet as result of post-stea.Menerator tt LOCA ficoding of tube-side of superheat section of steam-generators? Nculd sc.e tube failures at this point in tire seriously affect core cooling?
hnat is e.e. axicum seconcarf system pressure develeped after turoine trip with first subsec,uent cancom failure ceing loss of rain feeesater ficw centrol leading to ficoding of superneat section of steam generatcrs.
Assure turbine trip witncut 1:ypass (lcss of ecn-t i
denser vacuum).
l 6.
Cces applicant k$cw that time-dependent levels will occur in pecucurizer, stem generator and reactor vassel after a re.latively call primarf ecolant treak wnich causes ccolant to appecaca cc even partly un-ccver fuel pi::s? What dces eperator do in respect to interpreting level in gecucuriner?
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3 During priracy system refill frca hijh pressure in-jection pe:rps there is sc.Tc pericd wnen neitner condensation nor natural convecticn is present to How is effect heat transport to secondary side.
~
i transiticn to natural convection without_ assistance _
frca primary coolant ptnes cbtained.
' hat is tne particular design of the start-up oiping 7.
Cces it in-and pu.rping system for Pel:cle Springs?
volve cperating with a liquid-solid secondary sys:em?
Has the Staff perform 3d a safecy analysis of this 9
system?
Can the plant octain access to tne icw-pressure 5HR 8.
system f rom the high-pressure ccadition usino og safety crace equiguent?
Defend the rationale of having caly t,o active" I
9.
service syste:cs which scrform continuing or icng-term The first " accident" is the failure safety fur.ctiens.
of cne train thus dentrcying necral" redundancy.
Cagendence en a single system in ter.ns of consequence of failure of that cc: raining systca is ecsontial to intrinsic riska of such designs.
undarutandin-J I
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Cescribe each such system ano consequence of total failure of services provided cy that system as a functicn of time. Only " active" f ailures 'ccycno fitst f allure need 'ce censidered.
Pcssible 'exa:rples of such systems are:
1.
Sattery (DC peser sy stem) (consider carasitic
~~
Cn-site AC =ceer system - assuming prior 1 css 2.
of off-site AC system 3.
Service water system 4.
&cirpenent cooling system 5.
EnvircrTental control (hVAG) systens
" Redundancy" may ce egressed in ter::s of ti.~e to restcre service by any means whatever befcre undue ca.r. age ensues.
Knat are off-site dose levels resulting fecm Steam-10.
Generator tche failure, asscciated with icss of off-site
'41:at AC pcuer due to upset frem turbine generator trip?
is prccc.cility of such a grid failure folicwing tuccine trip?
Are any agecial precauticas taken fer stcraga and 4
11.
handling of hjdrazine?
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What is status of investigation of accits of a pria:ncy 12.
vessel coolant level indication systen for une in pcst LOCA ccoling for siell breaks?
The fire protectica system.my be characterized as a 13.
"hard" or " soft" system in respect to independence or dependance en fire detecticn and extinguishing systems.
In a local sense, in what particular locations is this plant dependent en administrative pectecticn and early 8
detecting-extinguishing tecnniques to protect vital
~
Is cceplete 'cucacut shutdcwn system f tcm fire camage?
assu::ad for local plant space or ar'ea such as ene spreading tcom?
As a general principle why is the design neavily I
14.
cependent en tne ccreenent ecoling systera for sate shutdcwn rather than using tne precc.ubly i.uce celiacle Ecta concepts are used in tne service water syste.n?
industry.
As an excrple of equiprent separatien wnica m.2y 15 be oveticcked, dascribe the coparaticn of the ec.n-preosccs fcr safety gt;de air c;oling syste.c.
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- 16. Descrite the inlet-ai.: protectica system for the min A
ccntrol rocm.
htat dose level would be imposed on operators after a LOCA with " realistic" celeases (:!ot TID) to ccntainnent but with a single failure 'ceing that of electrical bicw-cut of an inter:nediate si::e cenetration (say 10" dia.)?
- 17. Cescrite electrical protection for pcuer-carrying gene-traticns subject to in<cntairrent faulting during LCCA. Include penetration for rain ecolant pug:s.
Cescribe,:rctection in centext of toth overcurrent trip anc gecund f ault (arcing) proteccion to prevent electrical curnout and thus 1 css of mechanical integrity of the gene-tration.
Incluce penetraticas handling ncn-safety grade pcwer circuits.
- 13. Page 9.9 descrices what is apparently an electrical ecol-ing systera for Auxiliary 7ee8/ater Peg cco..s.
Civersity m
was the basis for requiring engine driven Aux. Ecodiater pt.ps, yet apparently electrically Ec. sered roc.n ecoling is necessary to assure the engine-driven function.
Pie:se clarify.
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In respect to the volcanic asn pccolem:
19.
Are tne diesel-angine air filters designed to prevent disaaling upt:ke of asn to tne a.
engine during tnis situatica?
l ted what other air uptakes have been eva uato ins b.
dcwn during this condition sucn as:
Ccattol cco;n ventilatica and ccoling Di.esel generator air ccoling Aux feed <ater engine air cooling Service water actor ecoling kny.otner critical air ccoling syste:n Fct a rain stern line failure insice contair,2nt 20.
folicwed Ly the first randem f ailure ceing that of l e to close, the cpgesite. rain stein line isolstica va v i
descrito hcw excess ficw is preventec threugh "nca-qualified" valve f ailures sucn as turbine cy-pass valves.
in In this connecticn, clarify the raticnale *.,hich, I
ident scan dauf.gns, nasces that the 1,arge LCCA is "coinc
(!)" with an carthque.ke ' cut, asse.ing no LCCA, tne f ailure of other kinds of "causive" ele:nnts (auc tolerated -
as main ster.a lines in centair.mnt) can".at c 2 a
failure f
since sucsequent applicaticn of the sinale rende.n i
critnica,cuid dcctroy etit.ical active aetv ces.
t 4
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-g-Are the main feewater isolation val /es cesignec to 21.
provide the closing functicn in a bi-directional ficw Is instrum.entation diversified to assure main sense?.
Oces this feedsater ficw interruption when ecquired?
include separate d-4: or inverter pcwered systems?
t What prevents scurious cicsure_ of rain feedsater systems in the lignt of the critical need to step such ficw when necessary? dhat is tne estimated frequency of sucn closures as tne original accioent?
e The SF.R indicates that certain caoles will ce tasted 22.
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for water resistance by stir:urgence.
jicw often will this te done and what is the peccaole frequency of expcsure to this ccnditica curing opera-ticn?
Is this scrt of testing program pecposed fcr the electrical wiring and penetraticns within centair rent.
If not, why not?
e In ence-thecugh stcar.-;enerator designs, the auxiliary 23.
feedsater system r,ust respcnd very pec.ptly af ter ain 1
feedsater is tripped. Furt 2: ore, the rain feedsater system'is prest ably assured to trip curing any signi-ficant seicmic event.
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_9 Against these conditicns it appears to ce poor practice not to seismically qualify the condensate storage tank as the viable " passive" source of critical fcedsater fol-lowing a postearthquake trip and shutdcwn. The present design cces not require this but, instead, depends en the electrically driven (stopped and restarted en oiesel pcwer) service water system to provide sucticn to the Auxiliary Feecaater pug s.
For this particular conditien, the advantage of the diverse engine driven Aux feedaater pu.ps _is Icst since suction must be provided cy the v
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electrically pcwered service water peg s.
w'ny has tne~ design evolved in tnis manner?
24.
Frca the standpoint of finding tne worse credible situation in the context of the maxi. um rate and degree of succcoling i
of the unbrcken primary coolant system, it appears that main steam line failure within ccatainTent (wnich dis-l-
ables pressuriner heaters and providas ECCS trip signals) ccupled with failure of Tain f2:daater trip, is pec' anly c
the worst ccnfiguratica (It is.also prest.? ably intoleracle, if persistent, frca the st:ndpcint of c:ntairent pres-surizatien).
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- L Discuss the consequences of this event in respect to:
cegree and ^ rapidity of return of fissicn pcwer l*
a.
after rod insertion.
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b.
Thermal gradients in most severely affected 1
parts of reactor vessel and steam generators and sucsequent sudden rise of prikaty coolant i
pressure to safety valve setpoints after enilling J
the interior face of the vessel.
i Maxima contaimunt' pressure as function of time -
c.
of continued run-on of main and/or auxiliary 4
i feedvater ficw to the failed steam generator, ti
- 25. In the startup of newer design B&d syst' ms, using comparatively e
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1 large purps and piping and using a water-solid seconcary system,
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the temgerature of the water in the seconcacy system is i
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o raised to 400-500 and sucsequently the secondary is drained until ner.Tal level is cbtained. Has the Staf f exanined tne safety aspects of tnis system?
1"
- 26. Ccasidering such matters as (1) off-site power failure, (2) ccndenser vacuum f ailure, (3) spuricus main feedsater valve closure (see item 21 preceding) and recent incicents of failures in auxiliary feedwater systers it aggears that, i
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si,ngle failure criteria nctwit: standing, at least short tera failures of the auxiliary feef.. uter systen musc be h
considered to estimate the nccded reliaoility of suca systen.
Wnat, for instance, culd be tne peak pri.Tary syste.n pres-sure, consequences to prirary ecolant systen safety and relief valves and rate of prir.2ry ccolant loss fc11cwing I
failure of the.'suxiliary fe; suter pc.:ps -hen needed?
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! \\"k,,. q / k NUCLEAR REGULATORY COr.it.11SSION f
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Aucust 23, 1973
. MEMOP,At: CUM FOP.: Chain::an Hendrie Coanissionce Gilinsky ayay m,, y g Comissioner Kennedy
/ r; p u, ^ M Cc:miissioner Bradford C
Comissioner Ahearne THRU:
Lee V. Gossick
. Executive Director for Operationg, ' g FROM:
Harold R. Denton, Director Office of tiuclear Reactor Regulation
SUBJECT:
RESUMPTIC:! 0F LICE?tSItiG REVIEUS FCR ::UCLEAR POWER PLAITS w.,..
In May of this year I described a realignmen't of current and near-tera pricrity tasks within the Office of l!uclear Reactor Pegulation (ii.U) to deal with activities relating to the accident at Three Mile, Island (see SECY-79-344).
One consequence of the realignment was a tempcrar'y celay in the processing of operating license and ccnstruction permit applications for nuclear piants pending cc pletion of certain TMI-2 related tasks.
The short-term TMI-2 tasks are essentially cceplete, as-summarized below, and based en the results of these efforts I have decided to resume staff
. licensing activities on pending construction perr.ti: and operating license applications.
It is my judgment that the TMI-2 related acticns being taken by tiRR on licensee e=crgency creparecness (see SECY-79-450), operater licensing (see SECY-79-33-E), buiietins and orders followup (primarily in the areas of auxiliary feedwater system reliability; loss of feedwater and sn:al' break loss-of-ccoiant accident analysis; emergency ocerating guidelines and prececures; and cperator training), and shcrt-term Lessons Learned, if accccolished generally cn the schecule zee have selected, are necessary and sufficient for the centinued safe cceration of ocerating plants and fcr the resumptien of staff licensing activities on pending construction permit and operating license applicaticns.
It is my intent to bring the staff's first cunpleted review ci a pencing coerating license application to the Ccm.;issica for revicu prior to staff issuance of the license.
The Lessons Learned Task Force and I also have considered whether the actions asscciated with these activities would foreclose other actions that subsequently may t'e shcwn to be necessary by the Lessons Learned Task Force, the President's Cecaission er the liRC Special Inquiry.
Wo have no indication that they will.
The Co=nission
, The principal element of the ccmposite of staff activities listed above is the completion of my review and the ACRS review of the first report of the TMI-2 Lessons Learned Task Force (tiUREG-0578). The Task Force report contains a set of reco=endations to be implemented in two stages over the next 16 months on operating plants, plants under construction, and pending construction permit applications. The Task Force recc= ended 20 licensing requirements and three rulemaking matters in 12 broad areas (nine in the area of derign and analysis and three in the area of operations).
A'. i but one of the 23 r eco=endations had a majority concurrence by the Task Force. The Task Force concluded that implementing its recomendations would provide substantial, additional protection which is required for the public health and safety.
The Advisory Comittee on Reactor Safeguards has completed its review of the Task Force report. The several public meetings of the ACRS subcc=nittee on TMI-2 and the public meeting of the full cemittee on Augus 9 provided an opper tunity for the presentation and discussion of public cements on the report. The ACRS letter of August 13, 1979, to Chairman Hendrie states that the Cc mittee agrees with the intent and substanca of all the Task Force recc cendations, except fcur upon whicnithe Comittee offered constructive cc=nents to achieve the same objecti\\.;es articulated by the Task Forcp. The Comaittee also noted that effective impi: mentation will require a more flexible, perhaps extended, schedule than proposed by the Task Force. A copy of the ACRS letter is provided as Enclosure 1.
The ACRS ccments en ::UREG-0578 concentrate en four of the Task Force recc=endations. These are:
(a) the revision of limiting condi:icns of operation to require plant shu" a for certain human or procedural errors; (b) the inerting of GI and II.
.s containments; (c) the crovisica of recctbiner capability a operating plants that do not already have it; and (d) the addition of a shift technical adviser at each c;'erating plant.
The first three of these matters require Ccrission rulemaking, and it is a straightforward matter for the staff to consider the cc=ents in the process of developing :he required Ccmission papers.
I will assure that is done.
l It is my intent to ask the Office of Standards Development (SD) to proceed l
expediticusly with a Comnission paper proposing a new rule on limiting conditions of c:'eration (ite 12, above).
I will ask SD to include in the paper the alternative apprcach recc= ended by the ACRS, and one other approsch that I :nink marits consideration. My alternative would amend the Task Force recc=endation so as to differentiate bet..een an isolated l
occurrence and a reectitive pattern.
For examole, the forced shutdcun aspect of the Task Force recerendation could be reserved for a repeat violation within a relatively shor: time period, such as two years.
The Cc: mission "
In the case of the two hydrogen control matters (items b and c, above), I
. intend to folicw the advice of the ACRS by asking 50 to delay completion
.of the required staff papers for proposed rulemaking until after receipt and review of the final report of the Lessons Learned Task Force, now scheduled for cc:pletion in mid-September.
It is likely that the inerting and recc:biner requirements rec 0= ended by the Task Force wili be included in the eventual solution to the hydrogen control problems encountered in the T:41-2 accident. However, in view of the short time until the availability of the overall hydrogen control rec =endations by the fask Force, I agree with the ACRS that it is best to not dilute staff effort in this area by prcmpt pursuit of the two short-tern recc=endations, one of wnich was a minority view cf the Task Force foi-these same reasons.
'he ACRS c:=ents on the shif t technical adviscr (item d, above) have i
resulted in our reassessment of the possible means of achieving the two functions which the Task Force intended to pro. vide by this requirement.
The two functions are accident assessment anrc::erating experience assessment by pecole ensite with engineering ccm::etence and certain other characteristics.
I agree with the Task Force that the shif t technical at, sor conceot is the preferable sh rt-tera cathed of supplying these functicns.
However, I have concluded that scme flexibility in implementation may yield the desired results if there is canagement innovation by individual licensees. The Task Force has pre::ared a statement of functional characteristics for the shift technical advisor that will be used by the staff in the review of any alternatives proposed by licensees.
It is provided here as Enclosure 2.
In addition to c:=enting on four of the Task-Force rec:=endations, the ACRS letter of August 13 rect = ends three additional instrumentation requirements for short-tern action. These are c:ntainment pressure, containment water level and con:ainment hydrogen c;nitors designed to folicw the course of an a :ident.
I agree with these rec =endations.
The Task Force h:s ;'re::ared descriptiens of these recuirements in the same format as Appendix A of NUTEG-0573. They are ;:rovided here in Enclosure 3.
I have also decided on one further licensing recuirement 'or short-term action.
It is a rcquirement for remotely crerable high point venting of gas from the rea:::r c:clant systen.
The Task Force has precared a description of this requircrent; it is provided here in Encicsure 4 The Task Force hd previcusly d2ferred this irta for further study, but it is my judgment that design efforts by licensees can and should be initiated now.
Finally, the Task Force has c: coiled a set of errata and clarifying co=ents for NUT.EG-C573.
It i: provided here as Enclosure 5.
The Comission
,-4 In summary, the Task Force reccmmended prompt licenning' action on 20 items (excluding the three rulemaking matters).
I have added the three additional
. requirements recommended by the ACRS in its August 13 letter and one more on the basis of my own review. This Office will issue letter: to all cocratino plant licensees and all construction permit and operating license applicants within the next two weeks requiring thm to commit within 30 days to meet the total of 24 licensing requirements to the implementation schedule provided here in Enclosure 6.
Ancther letter to be issued at approximately the same tu..:. vill state the requirements flowing frem the work by the Bulletins and Orders Task Force on operating plants whic's also need to be picked up on the license applications.
Severallicenseesh$veadvisedthatscmeofthehardwarechangesrequiredin liREG-OS78 can be acccmplished at much icwor cost during springtime refueling t.? ages in 1950. Fcr good c:r;? shown, we intend to c:nsicer such flexibility in the implementation schedules. The end date for full implementation of all licensing requirements has not been changed fro;.; the January 1,1981, date recc= ended by the Task Force. The implementation dates for the Coranission rulemaking actions will be established in the course of rulemaking.
p/
Harold R. Denton, Director Office of Nuclear Reacter Regulation Enc)csurec:
- 2. Alternatives to Shift Technical Advisors
- 3. Instrumentation to Monitor Centainment Condi tions
- 4. Installation of Remotely Ocerated High point Vents in the Reactor Coolant System
- 5. NUREG-0:~i Errata G. Implemenution of Requirements for Operating Plants and ple.nts in CL Revicw cc: Mitchell Rogovin Saul Levine Robert Minogue Victor Stello William Dircks Carlton Kamerer ACI'.S i