ML18047A337
| ML18047A337 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 04/01/1982 |
| From: | Diianni D Office of Nuclear Reactor Regulation |
| To: | Eisenhut D Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML18043B117 | List: |
| References | |
| TASK-2.K.3.07, TASK-TM NUDOCS 8205270433 | |
| Download: ML18047A337 (3) | |
Text
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DiYisicn cf Lic~~sing Tho -~ s u I..
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Robert A. C1ark; Chief f~eflc~
Operati_ng Reacto:rs Branch ~3; DL
- Dominic C. Di!anni, Project l~naoer Operating Reactors Branch t3, DL-HULTI PLANT ACTION ITEH II.K.3.7-POWER OPERATED RELIEF VALVE OPENING PROBABILITY Hy status report date'd January 21, 1982 recommended that Action P1an Item*
I I. K. 3.7 of NUREG-0737 be reeva 1 uated for _poss.i b1_e can.ce.11 ati on or redi*rec~
.t.ion fr.om~- tec:hnical....point.of view.-~
- Item II.K.3.7 requires licensees of B&W operating p1ants to derr~nstrate that the PORV*wi11 open less thari 5% of all anticipated overpressure
- transients-using the revised setpoint and anticipatory trips for the ranges of plant conditions occurring durirrg a fuel cyc1e.
The objective of this action.is to deterrn.irie, -by.* ~naiys'fs. and operating ex-*
perience, if the ?ORV challenges ar~ greater or less than 5% of the total nu;-;;be1:" of overpressure transi'Emts..
-~)~si_s.f9r __ autqrr~ti_DS. the_:b_i_o_c~_ya1ve __
to the PORV could be established if results show.that the EORV challenges r*-*-****--,,_-* -**,**-** r*---,*.* ****--*** "7".;.... --.-** "-' -*-**.
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nowever, 1r resu1i..s sh9w tnai.. challenges-~.. he.
- PORV *are 1 ess than 5%,
- it wou1 d then confirm: that the revised PORV set point reduces the PORY challenge to an acceptable 1eve1 and.no further system changes would be needed.
In ~y o~inion a deci$ion to autori~te the block va1ve based on iesu1ts from this action does not appear adequate, based on the following.
- 1. Tnis action_cfo:s not*co*nsider the operating history nor the 1ongeyity
- of the PCRV ii~i ch affects tne probabi1 i ty of adequate opera ti on of the PORV.* -~estricting Item II.K.3.7 to overpressure transients does not*
consider. ot~1er* rr.inua f cpe.rati ons-o*(-the *PbRV which wou1 d *; m6.act on the Qpenin_g-_and ciosing"_l5h)_babi1ity"when-require{dur1ng a transient.
O~her manua1 operations of the ?ORV wou1d include de-.gassing, norr.ia1 pressurizer
_venting~ or pressurizer vapor sp~ce.deve1oprnent which impact on the wear arid-~ear of the va1v~. Present1y technical spe~ification~ do not restrict the use cf the PORY.
- 2.
The probability ana1ysis was performed using -the best estimated nuii".::ers as input for the analysis for determining* the nu~ber of PORV actuations.
h'hetter. acC:itiona1 confidence can be gained by furthei q'.l:r,ying the licensees on thiS issue is open _to._question.* Such esti.mated numbers
,.~.:cession ~;: > 32*052 i04 33 as.* B~en* Sent to
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- . e. "r:*:~1c ~= C.ifficu1~ t6 jt;stify.
Hor.*ev:r, O?:rat~ona1 ex?E:iie:nce does indicate that 190 re~ctor trips wou1d have actu~ted the PO~Y with the pre T~I setpoint v~rsus 3 PORV actu~tions with the revised setpoint.
~~ s ed on this *data, the present POR\\'-cpeni ng prot-abi.1 i ty. is less th!n 1.6: which.could indicate that automating th~ ~b1ock. va1ve is nnt
- -.ecessary.
Ho;,*:ver, such a decision \\..'ou1-d*1ead tb a *false sense of security s i nee.i tern 1 above is not being considered. n-.e en ly. reasora-a bl e conclusion that can be d.rawn from the avai1ab1e information on this* action is that the revised PORV setpoint does reduce the number of challenges to the POKV1during plant transients.
- 3.
Basi*_ng any decision on t~e PORV c:h.a11enges at a s% 1eve1 is *also
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. questioned since ~here ts rio techni~a1 basis for selecting the S~ /
1 eve1 to ~ry~ best of* my know1 ege*.
- 4.
Eric1osures 1 and 2 address many areas in which the ~e1iabf1itj cf ~
- the ?ORV can be improved.
Any probability* analysis would be pre-
. rr..a tu re without first considering* so~e of these improvements.
The
-_> mission of the PORV has yet to be defined (note Enclosure. 2). This shoui d be *considered part of the overa.11 ;program.
In my judgement the.- pres.ent.actu.a.:tfng.s.etp.oint..;;.Qf.the.. P-DRV.-s.ho.u.ld b.e.:.,c..onstd.ered.....:.
- s an int.edrn position for the. reasons given in enclosures 1 and 2. -
!n acdition,.automating the block va1ve is on1y one of rr~ny areas t.h~t need to be studied an-d evaluated in this program ~s brought out in enclosure 2,
- 5. It requires the* coo*rd1na.tions of many disciplines {i.e. *Materials,**
"Het:hanical, Reactor systems, I&.C and E1ectrica1 Engineering) in **
order to upgrade the re 1 i ability of the PORV.
This coordi na ti ori is ~eeded ~ince these disciplines are interrelated when one considers their effects on the PORV.
I know ~f no single person at NRC that 1 s cc o r G 1 r1 a 1. i.il g
- 1. n 1 s e T r. or i.
- 1 r.e.3c bcock ~ h'i 1 cox (5£\\.:) oio\\ners group re-port (is sued on Janu~ry 1, 19.81) which a~dresses action 1tern:II~K.~!7 is being reviewed ~nder contract with Frank1in Research Center.
By our letter dated December 16, 1981, we requested that a licensee (ANC-1 1ead*p1ant) furnish additiona1 information within 45
- . days.
As it now stands, work on. the response is not s chedu1 ed to start until
- *May 1982 and a submitta1 to us is not expected until SepteMber 1982.
In conclusion, based on the above I cannot justify further consultant contract.
. work or contacts with 1icensees on action Plan item II.K.3.7 until th~ matter~
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Enc1osure: ~s stateo
- c.c:: P.. Denton E. Case
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J. F.unc:hes
- O. Garner R. C1ark R. Kattson
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H~.'nauer R. Vo11mer
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uc.* :iriic C. Di.:::... ni, ?r-oj:ct P:ar.::ger O?er~ti~g ~eectors Sr~nch ~3 Division of Licensing
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