ML19309G862
| ML19309G862 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom, Browns Ferry, Oyster Creek |
| Issue date: | 01/28/1980 |
| From: | Eisenhut D Office of Nuclear Reactor Regulation |
| To: | Gridley R GENERAL ELECTRIC CO. |
| Shared Package | |
| ML19309G857 | List: |
| References | |
| REF-GTECI-A-10, REF-GTECI-RV, TASK-05-04, TASK-A-10, TASK-OR, TASK-RR NUDOCS 8005070697 | |
| Download: ML19309G862 (5) | |
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January 28, 1980 Generic Technical Activity A-10
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Mr. Richard Gridley,' Manager....
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Fuel and Services Licensing ~
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General Electric.Corgany: -
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175 Curtner Avenue -
'1 San Jese, California 95215 D ea r ".r. G ri dl ey :
Since the initial discovery of cracting in boiling water reactor (SVR) control rod drive return line (CRDRL) nc::les in early 1977, General Electric (GE) has prepcsed a number of solutions to the problem in the course cf which several documents were sub:nitted for NRC staff review.
These d:cunents were as follows:
,1979, G. G. Sherwood (GE) to Y. Stello and Letter of March 1.
R. Mattsen (NRC) regarcing calculation of CRD system return flow capacicy; Letter of April 9,1979, G. G. Sherwood (GE) to Y. Stello and R. Mattson (NRC) forwarding results of CRD systes solenoid valve 2.
en.:rance testing; Le ter of May 1,1979, G. G. Sherwood (GE) to Y. Stelle and R. Mactson (NRC) forwarting results of CRD syste= solenoid valve 3.
perfor:ance testing; and Letter of Noveeber 2,1979, G. G. Sherwood (GE) to R. P. Snaider (NRC) forwarding additional information as requested recarding CRD 4
bycraulic system perfer:r.ance, especially with regard to corrosien procucts e:anating frc: carton steel piping.
All ccacerned the GE rationale for the latest proposed syste= modification to prevent no::le cracting; namely, total removal of the CRDRL and cutting Previcus submittals had presented the and ca:cinc of the CRDRL nc::le.
bases for i.he other =ccification propesals discussed herein.
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Mrs Ri:ha-c Gricley Janucry 23, 1980 Specifi:aily, your March 14, 1979 letter discussed the EI analysis performed after t e U.C's selectica of a base case f. use in cocparing capability to infect nigh pressu e water into the rea:t:r vessel when other water sources trere is:iated. This base case was the M75 incident at 3rewns Ferry Unit Xo.1, during which the' CRD system scretires was one of the only capahle The scu. ces Of high pressure water injection to keep the rea: tere core covered.
s'aff rec:g-i:es that the ;ressure of this capability had not been directly assu:ee: in any prtvious safety analysis. However, the critical need for the syste:.as again revealec.curin; the early 1979 incicent at the Oyster Creet ku: lear Ge erating Station. Coring this incident tne reactor vessel also was is:latec froc ether sources of high p essure water and the CRD syster v.aieep capa:ility helped preven; uncovering cf the active fuel.
Ycur analysis of March 14, 1979, included several assumptions which the NRC staff nas found acceptable. Principal a eng these was that concurrent cpera-i:. of the two CED pumps was possitie at any plant. This of course ic: lies that there will te ne electrical supply li=itations and no pu=p p;sitive suction., hest lx?SM) limits ina. will be reached.
Licensees ne an:,t:;1iInts will be re f ree to dem:nstrate this to be valic, by testing, p ri: r.: 0;r appr:ving CRD return line reeeval.
The 1e:.ers of April 9, and May 1,1979, discussed the solenoid valve testin; ; : gram initiated in respense to earlier WRC concerns. The original 1
a..aiysis Of CRDEL retcval vita ut rercuting deter ined that return flow to the te:::r vessel f-ce drive eperation would enter CRD cooling water lines an: e:u-n to the vessel rcu;n the CO me:hanis:s the=selves. During testir.;, h: wever,.you cis::verec :nat the actual path would be a reverse fi:w pt:.. :Ar:ugn the inse-e.aust directional control valves of the nc..-a:.uatec Mycraulic Cen rol Units. Tne long-ter= cycling of the control valves ir, the reverse dire: tion was a cause of WRC concern with regard to p:ssi:le ceietericus effects upon the operation of the CRD hycraulic system.
In' res;ense to this c:ncer., EI tested ten valves which had been removed fr:c t c:erating reactor en <nich the retrn line had been isolated for six acn:.s.
These valves were then cecet ed against tests performed on five new valves. The resuits shewed that the reverse ficw characteristier of all valves were sir.ilar and that de;rt:ation of-the valves to the point of 02usin; system r.alfun::icn v:uld net be expected during long-ter :
n:.-Il pera:icn cf tne sys.er.
The NRC suff is satisfied wi.h these r t sO'. ts.
r" iife cy:1e testing also was pe-f:vd en f'ive valves, resulting Sic /.1:e :
2: verse effe::s were :aused by tae bactflow.
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Mr. 'Richarc Gridley January 23, 1960 A
f our final letter of Neve=cer 2,1970, discussec in dettii your res;:nse to s aff cencerr.s regarcing pessiele degra:2:icn of ne CRD systec anc incivicaal CR0 sechanism de:ause of c:r :sf on pr:blem frA-caroon sael pipin;. Certain =:cifica icns were sugges:ac to solve nese problems.
You also ciscussec your re:comencations re;arding :ne installation ef pressure equali:ing valves in the CRD syste to prevent, under a hypo-tnetical transient, a large pressure cifferential across tne CRD system which could result in ex:essively fast acvement of a sele::ec control rod. The valves also prevent flow froc :ne carden steel piping of the norrai exhaus: wa er heacer :: tne crive c: cling water neacer.
Ve have reviewec your sut it als anc have concluced the following:
1.
Caly licensees of the fc11 ewing classes of plants will be alle=ed at this tice to imclement the rece=re-catien to cut and cap with no re-routing of tne CEDRL anc witneut furtner analysis. Eacn applicable
' ian must demonstrate, by testing, concurren; two CRD purg operation (with cne exception), satisf ac cry C7.D system cperaticn, requirec flow ca acili y, and eacn will de requirec :: install the sy: e m:cifica icns listed in 4. below.
a.
21E' EWR/6 3.
25i' EWE /6 c.
153' BWE/4 (only one pu=p neece: :: satisfy base case requirement) l 251' EWE /4
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'4: =ccificatiens shculd be perforrec :n operating reactors pri r to issuance cf the "For Cc= cent
- issue of XUREG-C513, sche:ulec for release in January 1950.
2.
Ve a: not accept the hypotnesis tr.a One calculati:ns for the above
- 1an s were bouncing. Therefore, price
- : our ap;r: val of mocification
- f ciner plan: classes, we snall re:uire analysis similar to snat per-f:rmec :n :ne plan; :lassts of 1. as:ve. The same testing and syste=
mocificati:ns will also be requirec.
1.
Ve f:unc :ne 251' SW:./5 ( ne fif a : lass anaiy:ec in the March 14, 1979 ie ter) presently :: de unaccep a:ie fer mocificati:n in that its calcu-i t ec fl ew fell :eit-One a :ep a:1e tase case value. Further analysis
- r pian -specific testing ::ul: p.:ve fio. capa:ity Oc de ac:eptacle.
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Mr. Richard Gridley January 25, 1933 4.
We will require that the folicwing :ocifications be i=plecented on all plants requesting the re=Cyal of De CEDRL without rtrouting and those which reroute but choose to operate with CRD return lirse flow valved out; a.
Installation of. equali:1ng valves between ce cocling water header and the exhaust water header.
b.
Flush ports installed at high and lo< points of exhaust water header piping run if carbon steel piping is retainec; and Replacement of carben steel pipe in the flow stabili:er loop with c.
stainless steel and rerouting directly to the coeling water header.
5.
Each licensee nus establish readily-available operating procedures for achieving maxicum CRD flew to an othe: vise isolated reactor vessel.
6.
Licensees who choose to rerate the CRDRL, either with or without centinuous return itne ficw to ne systers Deing tapped into, mst ac: the GE-reco cended pressure con:rci station t: ce cooling water
- h ea de r.
This station acts to buffer. hydraulic perturcations frec any connected system in orcer to prevent pressure flu: uations in the CRD systec.
M:cification 4.c is based upon our decision not to accept the "co n: thing" altemative addressed in your Wove =cer 2,1979 letter.
Ve consider the
'ocre absolute solution" (your characteri:ation) to be ce correct one and agree with your reco:mendation, made in accordance with mis
'r, ore absolute solution', tha the carbon steel piping should be elisinated. We cc net a::ept the option of filter ins:.allation as a means of trapping corrosion panicles that have a dele:ericus effe:: on the CRD meenanis=. Our con-cern is tna; improperly maintained filte: s on the cooling water header j
c:uld result in heatup of drive mechaniscs and the possieflity of multiple criYe f ailurts of a type nCt previously analy:ed.
M: e that we have discussed only the acceptacility of te latest GE rec:r-nenr.ation discussed in the four letters. Ve continue to ac:ept CRDRL re-routing to a line outside centair.oen that in tura provices the retum ficw to the rea::or vessel (valving out af ter re-routing results in other reput rements - see 4. and 6. aceve). Ve also find acceptacle, as a strictly interim masure, ce valving out of.he ORDRL. Hcvever, this will require inspe: icn, during ea:n refueling outage, of that portion of the itne c:ntaining stagnant water. We matter uni:h op f on is :nesen, we will re:uire cc:=lete inspectica, by cye penetrant technicues, of.the CRDRL n ::le, the apron area beneath the ne::le, anc the su sequent removal of any :racts f:und curing the inspect 2:n.
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a Mr. Ricnarc Gridley January 23,1g50 i
Fct the 3'G.s undergoing if censing revis and cesigned anc constractec without the CALE and its nc::le or metfied with the CR3RL cut anc capped without rer>;;ir.5, we will require testing (similar-to that for c;erating plants) to pr ye satisf actory system operation, return ficw capability equal to er in eness of the base case requirement dis =tssed above, and two pu:=p operation.
A;;ii ca:1e accifications of 4. above also rust be 1:;1emented.
We shall re:uire the establish..en of ope.ating procecures for achieving carisus CRD flo to an einersise
- isolated vessel.
Calculations with regare to base case retur 'ficw requirt ents sh:uld se subcitted, but in lieu of sucn calculations, the staff r.ay ac:e;t reference t: a beuncing analysis if necessary justification i s pr:vice d.
Ad:it':.a1 paidance en this subject will be contained in NUREG-0619. This do:::e..: is ter.atively schedulec for publication in February 1980.
Mincerely, 0 s-I
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... re 1 G. rfi senfiu.{, fi 4LL Acting Directer Division of Operating Reacters Office of Wuclear Reactor Regalation 4
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