ML19289G138
| ML19289G138 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 04/20/1979 |
| From: | Heltemes C Office of Nuclear Reactor Regulation |
| To: | Ross D Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 7906270001 | |
| Download: ML19289G138 (8) | |
Text
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D. Ross Jr.,
D:puty Director, viv1'
- nageo. ant, ?;RR u
FRCM.
J. Hel te res, Chief, Stan'"
.-ation ar a, Division of Project r-
,3nt y
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SL'E FCT-ACRS E C 0"PE'iDA T I ON: RELATIVE T0 i 11-2
..e ha a revie. ed the ACRS rec:...andations cc.ntained in their letters of April 7,18
=:d 20 resrectively.
In anticipation that the T:'!-2 bubconr.ittee will conduct a further inqu;ry into this area at the '<ay 31-June 1 meeting.,e have attempted to
- 3parate these reco' nendations into three categories:
1.
Shcrt-tain agartance - being adeque tely addrassed 2.
Short-ts:- inportance - additional action required; and, 3.
Lcng-tcc-i: gortance - should : e included under lessons learned activity.
In those cases where we believe additional action is required, we have attempted to define the aporopriate acticn, responsible person and schedule.
For the icng-term acticn ;e believe that we should dacu ent the basis for deferral and reach agreement cn the.2ndling of these items in advance of the Subconmittee meeting.
icur ccrments and/or concurrence would be appreciated on the pecpcsed resolution of cach item.
C. J. Heltc es, Chief Standardizaticn 3rsnch Civisien of Froject "1.
- nt Enclo:ure:
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7906 2 70CO[ '
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A.
April 7,1979 Letter - Mr. Car bcn to Chair, un leMrie Recon.mendation 1 - Perform further analyses of sma'l break transients and accidents.
- Statu_s,
. Review of extensive B&h' small break analysis included with orders; Review of small break analysis will be performed for all 'd/CE plants;
'!eed for additional work is recognized by staff and is addressed in SERs; C.a_tpSo rv - Short-term importance - being adequately addressed Raco -:.ication 2 Provide oper. - additional inforcation and means to follo./ the course of an accident; as a minimu.m consider expeditiously:
a) unarbiguous reactor vessel level indication; b) re.:otely controlled vent for reactor coolant system high points.
Status -
Staff studies (NUREG-0560) recogni cd the importance of these items
~
and reco:m ended additional work / study be initiated; the installation of such devices will require additional design studies, deveicpment r.nd testing - reactor operation can continue based upon present instrurentation Definitive staff pcsition needed related to staff requirements.
Category - Long-term significance - should be included under Lessons Learned activity Item 4b of IE3 79-CEA is censidered ta be und,uly")
Ricc: :ndation 3 -
s a
c.en prescr ptive.
Q'tus_ - Items il and Ib
.Je :ubsequently.Jdi fied by 2alletin 79-053 to pc nit cper der action.
Ni t'cnal di s cus;".cns :ra teing 'mid.si th re jard to the c:ncern o?!ressed by this Sulletin it n-Catecorv - S crt-term r pactance - being adequately c< med.
3
Pec.
c.dation 4 - For TMI-2 only, expedite discussion regarding contingency reasures for backup contairment ar.d reactor cooldcwn mean and p roce du re s.
Status.- Ccmplete - address in NUREG-0557 c '; vv - short-term n Jortance - adequately adir.'ssed.
B.
?pril 18, 1979 Letter - R. Fraley to the Cc mission Recc m daticn 1 - (a) Detailed analjsis of ratural circulation mode, supported as required by experiment by licensees and NSSS vendors.
Status -
"atural circulation and related opera ar actions are being ac' dressed in generic analyses by NSSS vendors.
Additional anal sis and related test requirements are being defined, 3
and c:ay also be addressed in latcr studiec Category - Short-term importance - being av.cquately addressed.
Reccmendaticn 1 - (b) Ce /elop procedures for initiating natural circulation S_tatus -
Specifically cosered in Bulletins and related evaivaticos:
Bulletin 70-05A (Item 3)79-05B (Item 1) 79-CGA (Item 2)79-06B (Item 2)
Procedures being reviewed as part of genaric vall break analysis.
Catecorv - Shcrt-term i cortance - neing udequately addressed.
Pe c r" 1:Q tion 1 - (c)
Frovide oper! tar ^ Ins for assurance that nat;ral circulaticn has been es' 'al :';ed, a.g., by ins talia:!cn of ins rn;tation to indica te ticw at icw /elocities.
s S t a t_a_s_:
Icocedures and tr aining related to operator activities for natural circulation are to include provision for deter'ining whether natural circulation has been installed.
'!rdars
',{ and CE - have provided informaticn to ACRS as to how operators can determine whether natural circulation has been established c.nd is continuing to be effective using presently installed plant instru.entaticn.
Since there are means to determine Wther natural circulation has N :n established, using presently installed instru.r,entation, rr wirements related to additienal fa cil i ty edifications, such as Ccw ficw indication will be studied under " lessons learned" activity.
CAe<gy_ - Short-tena irportance - additicnal action required Eggested action:
(1)
B&',l orders - Z. Roszteczy should ccnfirm that natural Ccxletion Date circulation procedures specifically address how the opc-rator (1) c/18 is to determine whether natural circulation has been (2)
U <3 established using only presently avai le (3) 5/23 instrumentation.
(4)
S/2S (2) E/CE - A. Thadani - should assure that the natural circulation procedures are specifically che:ked for this aspect.
(3)
Bulletin respcnse - Licensee responscs to IE Sulletins shculd be specifi.. iy checked with regard to his sus
.c.
(4) Assu:ning a pu:itive response is received cn actians 1-3, then an action itcm should be included under " lesson:
learned" activity wi th regard to acditicnal ins trunnts ticn.
ecr :ndaticn 1 (d)
Exp PH ticusly survey oper1 ting P.l?s to deternine.imtimr suitable armn gents of pressurizer hca tars nd r':-l i ml e c.-site pc,ser distribution can be cecvi'ied.
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m Status:
..:ly !.ulletin 79-053 (:ta ' lb) ?ddressed the need to assure adequate capa ity of pressurizer heaters.
CE/E - infor.naticn has bean requested related to "Cescribe how the plant can be safety cooled with loss of off-site pcv.er in these evaluations - including natural circulation.
W and TVA described arran;2 rents for pcwering heaters fecm vital buses and dieselr.
Category - Short-term impcrtance - additional action recuired_
Suggested action:
(1)
Bulletin evaluation team quickly check respcnses to 79-053 Corpletion Cate with regard to this item - confirm that suitable arrangenents (1) 5/18 have been made for assuring power to P7".
(2) 5/28 (2) Assure this item is included in M/CE Thadani repo. t -
(3) 5/28 effort should be expanded to specifically address each plant.
(3) Action item should be included under " lessons learned" to assurc staff requirements and review plans / process adequately address this item.
Recc=endaticn (e) Operator should be adequately informed concerning ieactor coolant system conditions which affect natural circulation
' ility, e.g., indication that reactor coolant systam is cc approaching saturation conditions by sui' cable display to cperator of T '
and pressurizer pressure in conjunction C
H with steam tables, and use of ficw exit temperature indication by fuel assenbly therroccuples, where available.
S taf u s_-
Bulletins inply a need for operators to quickly and accurately deter.nine 0
degrees of - dcccling - i.e., maintained primary syst:m zbcooled 50 F.
aed for specific instrumentation and suitable operator.arning devic]s for degrees of subcooling will be studied under "lesscns learned" or7
~' F 9 activity.
L J._
Cat >ary:
Short-Lern i~ ort?.nce - additival action required.
Suggested Actions:
(1)
BSN task force (Rosztoczy) verify that all licensees Cc-eletion Dates _
have identified a practical method by which operators (1) 5/i8 can determine degrees of subcooling.
(2) 5/28 (2)
Sulletin evaluation te3.a confirm that all licensees (3)
SF3 have identified a practical met':cd fre operators to determine degree of subcooling.
(3) t;eed for additicnal instrumentation with regard to this iten to be investigated as part of " lessons learned" activity.
(4) We shuuld take a strong ?osition that the ACRS recomendation with regard to operator determination of subcooling is a vital require ents.
- ote
(1) core exit themocouples are addressed in next item.
(2) discussions continue with ',[ on whether 50 subcool is necessary before HPI is terminated - W proposed nethods do not involve subccoling deter.ination Rece endation 2 - Ther occuples used to measure fue' assembly exit terperature to determine core performance should be used, where currently available, to guide operator concerning core stnus (full range capability).
Status:
- Some utilities have initiated this change.
Catecorv:
Shcrt-tem
-portance - additional action reauired Suggested action - (1) staff assignmnt should be nade (bulle _in evalu stion sugges ted) to determine:
(a) t.hich plants have T/C-installed and (b)
..hich pl.mts hava full cuage cagility.
(2) staff should request all licensees to ccnvert readout to
~(-/
,r full rance c a-Oiiity; ni._
/
3..
..lc (3) r4 r.c.nts en instaliatien of T/C aum readout range should be studied under "lassans learned" activity.
Rac: an.fation 2 - Operating reactors should be given priority regarding definition iiiple: entation of instrumentativa to diagnose and follo.v the.
c.
course of an accident, including (a). 3 roved rargling procedures under accident conditions and (b) irpec,ed techniques to provide guidance to offsite authorities.
Status: -
Staff racognizes the importance of this work and that priority should be glaced on achiuving an apprcved capability in cperating reactors at a first priority.
Catecory - Long-term significance - include under " lessons learned" activity.
acc. nsndation 4 - Reiterates previous recon:rendations that high pricrity be r
given to "research to improve reactor safety" (a) research on behavior of LWP.s during anomalous transients (b)
NRC to devalco capability to siculate range of postulated transients and accident conditions.
Status: Staff recognizes u.portance of this task.
Catecorv: Long-term significance - this activity will be included under "lcssens learned" activity.
F2cc rencatico 5 - Ccnsideraticn should be gi'.:n to additional monitoring of ESF equipment status, and to supporting services, to help assure availability at all tii c25.
Status:
The incrt:nce of this ;t u has 'xan stres:cd in bulletins:
79-05A (Itars 5, 7, 8, 10 ? 11)
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- u 10)
/9-CG (It;is 1, 5, 8 di 79-0C5 ('tcs 1, 4, 7 9, 3)
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Ia s addressed in 0: !:rs (e.g., ito.1 2)
Sbculd be revie',,ed adar "lesscns learned"
Cat :arv - Shoit-t_ r,,. ance - being adequately addressed Succested action - (1) need for additional requirements such as QA verificaticn; Ccr letien Date check nculd be addressed under " lessons learned" activity.
5l2S C
April 20,1979 let'.er - M Carlson to Acting Chairran Gilinsky Rece.cncation 1 - Initiate ir..ediately a survey of operating procedures far achieving natural circulation including:
(a) e-2nt involving loss of offsite pc,.er (b) consideration of role of pressurizer heaters.
St'tus:
Staff is investinatina those items as part of vendor generic studies noted earlier.
Cateeorv:
- Short-term irportance - being adequately addressed.
Succosted Acticn - Confirm that B&W ceneric work and W/CE in fact address natural circulation with loss of offsite power and with specific focus en PZR heaters - if not - slight to Icng-tenq.
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- 7. g ACRS ECOMMENDATIONS I
1.
APRIL 7,1979 LETTER A.
Recommendation Perform further analyses of small break transients and accidents
( All PWR's).
Orders on BSW plants specifically ir clude NRC Action:
e
" complete analysis for small breaks" review will be completed before startup.
Staff evaluations for CE/W plants include small e
break analysis performed by vendors.
Need for additional analysis work is recognized e
by staff.
B.
Recommenda tion - All PWR's Provide operator additional information and means to follow the course of an a:cident; as a minimum, consider expeditiously:
(a) unambiguous RV level indication (b) remotely controlled vent for RCS high points Staff recognizes need for additional work and requ re-NRC Action: e ments related to RV level indication and remotely controlled vent.
Reg. Guide 1.97 will be revised.
e
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A;RS Recommendations C.
I'.am 4b of Bulletin 79-05 A considered unduly prescriptive in view of uncertainties in predicting course of anomalous small break transients /
accidents.
NRC Action:
Items 4a and 4b were subsequently modified by Bulletin 79-05B to permit operator action to assure continued safe plant conditions and to account for reactor vessel integrity considerations.
D.
Recommendation - (TMI-2 only)
Expedite decisions regarding contingency measures for backup contain-ment and reactor cooldown means and procedures.
NRC Action:
Compl e te d II. APRIL 17 LETTER - All PWR's)
A.
Recommendation - Natural Circulation-related Items
- 1. Detailed analyses of natural circulation mode, supported as sj required by experiment, by licensees and NSSS vendors.
s Natural circulati$n and related operator action NRC Action: o included in generic analyses for B&W ar.J CE/W plants.
e Additional analysis and related test requirements will be defined later.
'l
- 2. Develop procedures for initiating natural circulation.
NRC Action:
a Specifically covered in Bulletics-Bulletin 79-05A (item 3)
Bulletin 79-05B (item 1)
Bulletin 79-06A (item 2)
, Bulletin 79-06B (item 2) e See response to recommendation 1 above.
E' Y A ' l
6 ACRS Recommendations 3. Provi6e operator means for assurance that natural circulation has been established, 2.g.,
by installation of instructions to indicate flow at low velocities.
NRC Action:
o Procedures and training related to operator actions for natural circulation covered in Recommendation 2 above.
Facility modifications related to low flow e
indication will be studied under " lessons learned" activity.
- 4. Expeditiously survey operating P'WR's to determine whether suitable arrangements of PZR heaters and reliable on-site power distribution can be provided to assure this vital aspect of natural circulation capability.
NRC Actio :
e Sulletin 79-05B (item lb) addressed need to assure l
j adequate capacity of pressurizer heaters.
s s_
3 x
s Additional review will be performed under " lessons ys
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learned" activity.
I
- 5. Operator should be adequately informed concerning RCS conditions which affect natural circu'ation capability, e.g.
(a) indication that RCE is approaching saturation condition by ar PZR pressure in suitable display to operator of Tc&Th conjunction with steam tables (b) use of ficw exit temperature indicator by fuel assembly thermocouples, where available NRC Action:
e Bulletin items on natural circulation and core cooling emphasize need to assure primary system is subcooled by at least 500 F. (e.g.,79-05B item 1),
Add.itional requirements and facility modifications o
will be assessed under " lessons learned" activity.
/R9 l G I.
s=
s.
ACRS Recommendations B.
Recommendation Thermocouples used to measure fuel assembly exit temperatures to determine core performance should be used, where currently available, to guide operator concerning core statu' (full range capa'allity).
Requirements have not been established on this : tem, NRC Action:
e but some utilities have made this change.
e Assessment will be made as part of " lessons learned" activity.
C.
Recommendatial Operating reactors should be given priority regardino definition and implementation of instrumentation to diagnose cod follow the course of a serious accident, including (3) improved sampling procedures u 4er accident cone.itions (b) improved techniques to provide guidance to offsite authorities NRC Action:
' Agreed' - appropriate requirements will be evaluated as part of " lessons learned" activity.
D.
Refommendation Reiterates previous rec;mmendations that high priority be given to "research to improve reactor safety" (a) research on behavior of LWR's during ancmalous transients (b) NRC to develop capability to simulate wide range of postulated transients and accident conditions NRC Action:
a Research needs will be specifically included as part of " lessons learned" activity, o TMI-2 activity did invalve extensive use of R&D ceganizations and specific simulation E.
Recccmendation Consideration should be given to additional monitoring of ESF equipment status, and to supporting services, to hel, assure availability at all times.
ACRS, Recommendations Specifically addressed in Bulletins:
NRC Action:
e Bulletin 79-05A (iters 5, 7, 8,10,,& 11).
Bulletin 79-05B (item 2)
Bulletin 79-06 A (items 1, 5, 8, & 10)
Bulletin 79-06B (items 1. 4, 7, & 9)
Specifically addressed in issued Orders (e.g., item 2) e Additional requirements to be addressed in " lessons e
learned" activity.
III. APRIL 20, 1979 LETT_ER A.
Recommendation Initiate immediately a survey of operating procedures for achieving natural circulation, including:
(a) event involving loss of offsite power (b) consideration of role of PZR heaters NRC Action: Actions indicated in other recommendations.
Additional NRC Action:
ACRS Recommendation contained in letters dated April 17 and 20 were transmitted to all licensees via ISE Bulletin 79-058.
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