ML19224B742
| ML19224B742 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 05/10/1979 |
| From: | Advisory Committee on Reactor Safeguards |
| To: | Advisory Committee on Reactor Safeguards |
| References | |
| ACRS-M-0114, ACRS-M-114, NUDOCS 7906220178 | |
| Download: ML19224B742 (4) | |
Text
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ACRS RF"bP'EliD?l l 0' S d/ //
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APRIL 7,1979 LETTER b (22]
A.
Recorn : n da t ion Perfern further enalyses of small break transients and accidents
( Al l l'..R 's ).
i fiRC Action:
o O rde rs on D r.'..' plants specifically include "complcte analysis for sr.ill breats' - reviest will be ccmpleted txf ore startup.
Staff evalu.itions for CE/i! plants include small o
breal analysis perfor; cd by vendors.
o I;eed fer additional anclysis wori; is recognized by staff.
B.
Recer cndation - All P..' 0 ' s Provide operstor additionel in formation cnd reans to follo.. the c o u r s e. of an accident; as c minimum, consider ex,reditiously:
(a) unarbiguous RV level indication (b) remotely controlled vent for r.CS hi gh points I;RC l.ction : e Staf f recognizes need for additional work and require-rents rel/ ted to RV level indication and rerrotely g
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controlled vent.
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o Reg. Guide 1.97 will be revised.
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ACRS f.eco :.cndations,
C.
Reco:. anda tion - (C W PWR's)
Item 4b of Bulletin 79-05A considered u. duly prescri'tive in view of uncertainties in predicting cour se of en lous s :li break transients /
accidints.
I;RC Action:
Items 4a and 4b u re sub:
. ly r'idified by Bulletin 79-05B to pernit ope ra tm tion t o a r t u re con t. inued m
safe plant conj;1 ions anc t:.. c c o u n t for reactor vessel integrity con si A:rati on s.
D.
Recoc : no tion - (T 4I-2 only)
E>podite decisions regarding conting.nc. i rv sut us f or i;ackup conta in-nient and reactor cooldown : t ms and pr u i dures.
l'RC Action ;
Co pleted II.
AFRIL 17 LETTER - All F;!R's)
A.
Rece mcnd? tion - liatural Circ ulation-relmted a tens
- 1. De t a i l e d an a l ys -: s o f n a t u : ;.1 ci
'!o< ion moce, supported as required by experit.ent, by licensen and i;E55 vendors.
fiRC Action: e Natural circulation and related c; </rator action included in pneric analyses for LM.' and CE/g pl a n t s.
o Additional analysis and related test require:ents will be ce fir.ed later
- 2. Develop procedures for initiating natural circulation.
I!RC Action:
c Specifically covered in Bulletins-Bulletin 73-05A (item 3)
Bulletin 79-DEB (item 1)
Bulletin 79-06 A (item 2)
,Bulletin 79-003 (itc 2) e See response to re c o:.
mdation 1 above.
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- 3. Fruv i ' o; f rator i:" ins for a nurance that natural circulation l as F w n mtabli shed, e.g., by installation of instructions to indic,^. f l c v.- at lou velocities, Procedures n.;d training related to operator fiflC /s *aon:
c, actions for natural circulation covered in heco: ;endation 2 above.
ficility todi fications related to. low flow o
indication will ht studied under " lessons l e a rn e ci" activity.
/.. Expsui. icu.ly surcy operating P!lR's to determine whether suitable arrent.
nts of Fu heaters and reliable on-site power distribution can N ga c i de c: to essure this vital aspect of natural circulation capbility.
Bulletin 79-05B (item lb) addressed need to assure fiRC /ction:
c e daquate capacity of pressurizer heaters.
/cditional revie'. will in performed under " lessons c
learr.ed" activity.
- 5. Operator shoule be adequately ir. formed concerning RC5 conditions which eifect natural circulation capability. e.g.
(a) indicatien that RCS is approaching saturatien condition by suitoble dioplay to operator of T &T nd PZR pressure in c
h conjunction with steam tables (b) use of flo. cxit terparature indica or by ftel Msembly t he r; acoupl es, wr.e re avail able I;RC /sclion :
o Bulletin items on natural circulation and ccre cooling erphasize need to assure primary system is subcooled by at least 500 F. (e.g.,79-05B iten 1),
o /.tiitional requircrents and facility modifications will te assesned under " lessons learned" ac+ ivity.
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ACRS Recommendations B.
Peco:r enda tion Therrocouples used to ncesure fuel assembly exit temperatures to core nerformance should Le used, where currently available, to guide operator concerning core status (full range capability).
determine Requircnents have not been established on this item, NRC Action:
o but some utilities have made this change.
Assessmer.t will be cade at part of " lessons learned" o
- activity, C.
Recermendation Operating reactors should be given priority regarding definition and and follow the course implez.entation of instrur:.entation to diagnos of a se riou:, accident, inciu jing (a) improved sampling procedures under accident conditions (b) improved techniques to provide guidance to offsite authorities
' Agreed' - appropriate requirements will be evaluated NRC Action:
as part of " lessons icarned" activity.
1 D.
Recor endation Reiterates previous reccnendations that high priority be given to "research to inprove reactor safety" (a) resear ch on behavior of LWR's during anomalous transients (b) NRC to develop cap::bility to simulate wide range of postulated transients and accident conditions Research needs will be spccifically included as part NRC Action:
o of " lessons learned" activity, TMI-2 activity did involve extensive use of R&D e
organizr tions and specific simalation E.
Re;o: andatic, shou!d f.e given to udditional monitoring of fSF equi [.
2nt Consideratior supporting services, to help assure availability at all status, and to t hr.es.
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ACRS Reco.endations.
Specifically addressed in Bulletins:
URC Action:
e Bulletin 79-05 A (iten 5, 7, C,10, & 11).
Bulletin 79-0b0 (item 2)
Bulletin 79-CG A (items 1, 5, 8, & luf Bulletin 79-0GB (item-1, 4, 7, & 9)
Specifically addressed in issued Orders (e.g., item 2) o Additional requirarents to be a ddressed in "lesscos o
learned" activity.
III. APRIL 20, 1979 LETTER A.
Fetc.rendation Initiate ir ediately a survey of operating procedures for achieving natural ci rculction, including:
(a) event involving loss of of fsite poster (b) consideration of role of PZR f. caters NRC Action:
Actions indicatcd in other re;crmendations.
Additional llRC Action:
ACR5 Reco nandatica contained in letters datec /,pril 17 cnd 20 were transmitted to all licensees via 15!Bulletin 79-058.
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