ML19210C876

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Summary of 791026 Meeting W/Util & Bechtel Re Structural Integrity of Walls,Considering Piping & Equipment Support Reactions
ML19210C876
Person / Time
Site: Trojan File:Portland General Electric icon.png
Issue date: 11/08/1979
From: Trammell C
Office of Nuclear Reactor Regulation
To:
Office of Nuclear Reactor Regulation
Shared Package
ML19210C865 List:
References
NUDOCS 7911200248
Download: ML19210C876 (8)
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NOV 8 1979 Docket No. 50-344 Licensee: Portland General Electric Company (PGE) Facility: Trojan Nuclear Plant

SUMMARY

OF MEETING HELD ON OCTOBER 26, 1979, WITH PORTLAND GENERAL ELECTRIC COMPANY AND BECHTEL TO DISCUSS STRUCTURAL INTEGRITY OF WALLS CONSIDERING PIPING AND EQUIPMENT SUPPORT REACTIONS AT TROJAN NUCLEAR PLAhT On October 26, 1979, the NRC staff met with representatives of PGE and Bechtel to discuss the structural integrity of certain Trojan walls considering piping and equipment support reactions under earthquake conditions. A list of attendees is contained in Attachment I. Highlights of the meeting are summarized below. Attachment 2 served as the meeting agenda. On October 12, 1979, Trojan was shut.down to repair primary-to-secondary leakage in the A and D steam generators and to conduct an inspection of piping supports in inaccessible areas as required by IE Bulletin 79-14. The plant is currently in the cold shutdown condition. Both the A and D steam generator manways are open. The reactor coolant systen is drained to the " half-pipe" level of the reactor vessel nozzles. Decay heat is being removed in the normal manner using the residual heat removal (RHR) system. In continuing the inspections required by Bulletin 79-02 and 79-14, a problem was discovered in seismic anchor SA-83. This device anchors a portion of the pipe that connects the RHR system to the spent fuel pool and is used when the reactor core has been transferred to the spent fuel pool. This pipe is connected to the suction header which joins both RHR pumps. The problem that was discovered was that the structural integrity of the wall to which SA-83 was attached (by concrete expansion anchor bolts) was not adequate to resist reaction forces from attached piping.* This wall separates the east and west RHR pump rooms, and, as it rises from el. 5', becomes a pipe chase separating the two trains up to el. 45'. The finding was identified as a possible problem on October 17,1979 while conducting a base-plate flexibility analysis for SA-83. By October 19, after further investigation of the metter, the SA-33 problem was confirmed, and orally reported to NRC that day. This was subsequently confirmed in writing by PGE on October 22, 1979.

  • A double wythe concrete block wall, with grouted cells and rebar.

1363 307 7 9112 00 c) s

p Qfr D i Al$]m sh]D NM Nfru Meeting Summary for Trojan An imediate action letter was transmitted by IE Region V on October 22, 1979, confirming PGE's comitment to provide NRC with full information as to the nature and extent of the problem - and correc:ive action - prior to resuming operation. The SA-83 anchor is especially important since its failure could result in significantly exceeding yield stress in the cor:ron suction line from the normal RHR letdown path. This could result in the loss of capability of both RHR pumps from taking suction from the reactor :colant system and the refueling water storage tank (RWST). Bechtel explained that, with respect to this one wall, acmal design procedures were apparently not followed in that the wall was not checked following the detailed pipe support design (by Bercen-Patterson) to ensure its adequacy to carry reaction forces from attachec piping. As a result, this wall must either be strengthened or equip ent/ piping attached to other places to reduce the load on the wall. At the present time, SA-83 is being removed from this wall. The pipe will be atta:hed to a steel beam spanning the other walls. This is scheduled for cc=pletion by Sunday, October 27, 1979, at which time all RWST and RHR sucticn pising will be below yield and would be considered operable.* In the interin, PGE has developed procedures to maintain core cooling in the event of a severe earthquake and associated pipe rupture. This procedure was discussed at the meeting and is described in Attachment 3. The NRC staff stated that the reactor vess:1 level instrument should be made reduncant or readily recoverable and that the 2 submersible pumps should be set in place. Restoration efforts should put first priority on the ncrmal RHR system. PGE/Bechtel is investigating to see if the problem with the wall associated with SA-83 is an isolated case or if the problem extencs to other walls. A survey of similar concrete block walls and attached equip ent/ pipe anchors, restraints, and supports is underway. As for the SA-83 wall, there are 48 supports attached to it. Results: 24 - Acceptable as is. 24 - Corrective action being taken as follows: 5 - to be thru-bolted 19 - to be removed frca wall'*

  • All such piping will not necessarily be below Code allcwable stresses, however, until further investigations / modifications are completed.
    • Removal does not in all cases indicate it was recuired.
n some cases, due to piping geometry, it was easier to accomplish.

1363 308

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D o l\\ld AO c JB Meeting. mary for 1 a Trojan PGE/Bechtel has to date conducted a walk-down of 21 similar walls with similar large supports. The 21 walls were selected on the basis of wall thickness and nhether or not piping / equipment was attached thereto. No shear walls are involved at this point. Walls less than 14" thick with attached piping 3" or greater or having significant nechanical equipment supports are being investigated. Sixty-two supports on the 21 walls have been identifiet. Forty-five of the 62 were of priority interest because they are associated with piping in reactor cooling systems: safety injection, RHR, charging, boron addition. Results: 10 - Acceptable as is. 23 - To be thru-bolted instead of anchor-bolted to pick up both wythes of concrete block. 12 - To be removed from wall. T!i The balance (17 of 62) are of lesser priority (spray system, isolable parts of safety injection and RHR system, component cooling water, room coolers, etc.) and are not associated with normal r%r cooling systems in the present shutdown mode. PGE estimates that 10 days to 2 weeks will be reqtired to complete the wall / support survey and complete any necessary corrective action. Bechtel stated that the problems identified to date are due to either: (a) lack of post-desf p hanger review or (b) questionable a~dequacy of the original design criterin for the walls considering support reactions. To expedite the return to operation of Trojan, Bechtel stated that many of the changes are being made on the conservative side to save analysis time. Some supoorts are in the " judgment call zane" and are being modified also to dispense with possible differens:es of opinion. For example, if only one wythe of a double wythe con: rete block wall is questionable or is in the judgment zone, it was decided to thru-bolt the support to pick up both wythes to eliminate any question of adequacy. 1363 309

Meeting Sumary for Trojan The 21 walls studied to date were picked because of their irportance to reactor cooling in the present cold shutdown mode. Some 80 walls in all will be checked. Any necessary corrective action to restore the wall / support system integrity to appropriate levels will be accomplished prior to plant startup. PGE will be documenting this problem and associated corrective action in a written 14-day report required by the Technical Specifications. CMi /ramd!W C. M. Tramell, Project Manager Operating Reactors Branch #1 Division of Operating Reactors e 1363 310

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  • Meeting Summary for

. l Trojan Docket Files NRC PDR Mr. Jack W. Lentsch, Manager Local PDR Generation Licensing and Analysis ORBI Reading Portland General Electric Company NRR Reading 121 S.W. Salmon Street Portland, Oregon 97204 H. Denton ~, E. Case ~ D. Eisenhut Columbia County Courthouse B. Grimes 1 aw Library, Circuit Court Room R. Vollmer-St. Helens, Oregon 97501 J. Miller L. Shao Director, Oregon Department of Energy W. Gammill Labor and Industries Building, Room 111 G. Zech Salem, Oregon 97310 A. Schwencer D. Ziemann Dr. Hugh D. Paxton P. Check 1220 41st Street G. Lainas Los Alamos, New Mexico 87544 D. Davis B. Grimes Michael Malmrose T. J. Cartei-U. S. Nuclear Regulatory Commission T. Ippolito Trojan Nuclear P1 ant D. Crutchfield p, o, gox 0 R. Reid Rainier, Oregon 97048 V. Noonan. G. Knighton Dr. Kenneth A. McCollom.' Dean D. Brinkman Division of Engineering, P. T. Kuo Architecture and Technology . Project Manager Oklahoma State University OELO Stillwater, Oklahoma 74074 OSD (3) S Showe I&E Mr. Eugene Rosolie C. Parrish/P. Kreutzer Coalition for Safe Power R. Fraley, ACRS (16) 215 S.E. 9th Avenue TERA Portland, Oregon 97214 M. Milltr ASLB. - William Kinsey, Esquire. Richard M. Sandvik, Esquire 1002 N.E. Holladay Frank W. Ostrander, Jr. Counsel for Oregon Dept. of Portland, Oregon 97232 Energy R'onald W. Johnson, Esquire 500 Pacific Building 520 S.W. Yamhill Corporate Attorney Portland, Oregon 97204 Portland General Electric Company 121 S.W. Salmon Street Maurice Axelrad, Esquire Dnctland. Oregon 97204 Lowenstein, Newman, Reis, Axelrad and Toll Suite 1214 1025 Connecticut Avenue, N.W. Washington, D. C. 20036 136_3 3II Ms. Nina Bell 728 S.E. 26th Street Portiand, Oregon 97214

~ ATTACHMENT 1 List of Attendees Structural integrity of Walls Supporting Piping and Equipment Trojan Nuclear Plant October 26, 1979 NRC Staff PGE C. Tranmell W. Lindblad K. Herring D. Herborn

8. D. Liaw T. Bushnell H. Wong F. Rogan J. Gray H. McGurren G. Lanik Bechtel J. Zudans i

K. Wichman W. White G. Lainas D. Halligan D. L. Damon Other P M. Axelrad, Lowenstein, Neuman, Reis, Axelrad, & Toll B. Churchill, Shaw, Pittman, Potts & Trowbridge 1363 312

ATTACHMENT 2 Items to be addressed by PGE at 10/24/79 meeting RE: Structural integrity of walls co'nsidering piping and equipment support reactions, 1) Detaile'd description of the condition (i.e. failure to design structural elements for support reactions) on the Aux. B1dg. wall on which the problem was first identified. 2) Reasons for the existence of this condition. 3) The extent to which this condition exists elsewhere and the basis for this determination 4) Status of the review of other walls or other areas where this condition exists.

5) All systems, safety and non-safety, potentially affected.

6) Criteria (loads, and load combinations and acceptance criteria) for the evaluation of existing walls, any necessary modifications, and the evaluation of the equipment and piping. 7) Potential License violations including bases for determinations in this regard. 8) Postulate failure of all systems attached to the walls of the Control / Auxiliary / Fuel Bldg. complex. Discuss your contingency plan to provide core cooling capability and the time periods in which it is necessary to initiate this plan. ~ 1363 313

Alternate Core Cooling Procedure Present Plant Conditions (as of 10/26/79) Tav=135'F Shutdown time = 14 days 9ecay heat = 30 million BTU /H i RHR loop in operation Required makeup rate (boiling heat transfer) = 60 gpm Time to boil = 1.1-1.2 hrs Procedure (Reviewed and concurred by on-site and off-site review cormittees) 1. Open manual vessel head vent valve. 2. Use accumulators to inject flow to vessel intermittently. 7-8 hours of makeup available. Only 4 hrs assumed available to account for spillage. Note: Without makeup at all, it would take 4 hrs. for vessel water level to drop from the 1/2 pipe level to the top of the fuel. 3. Connect electric - driven submersible pump from RWST via fire hose to another submersible pump. Connect to test vent on hot leg SIS injection lines outside containment. 4 hrs. assumed for rigging time 4 day water supply from RWST. 4. Connect containment recirelation sump discharge line vents to a pump and heat exchanger (turbine bearing heat exchanger), thence to SIS lines as above. 5. If any line from RWST ruptures, RWST would drain to Aux. Building, el.5' and flood to about el.20'. Follow step 3 as above, except place pump in aux. bldg. 6. Use diesel-driven fire water pump (intake structure) to supply containment cooling function. 1363 314

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._ - a_c_t_obeF2 21 '19791cf.ri, firming the oral ~ report on' October,.19 cT. 977~ofV- .O . restraint on the. Spent Fuel. Fool Cooling System;,'~ ~ n ina equare seismic. - - -. vp_-- T - -.-;,nl(Si2-835 enclosed fB7 Licensee Event Report '7 9-15 which-describis '.tE.~n'---* . =.w_.w. = m,c ' T. a.T. ~.o.c, a ove'rstress conditions in : walls due 'to'1'oads from atr.a-e, w . 0ur.,investigatt n. -.hh d' ' ' 'J i i tt K on several safety. systems. ~ ~ o ., [.,pe sm g_ rc e _a n analyses [tg. ds,te, fr^e'" described in[tihe enclosed,Reporta ble'Occui fe,nd.F ^ ~ e I was 'advlsed by'Mr'.' Faulkenberry of your office" on Friday,' NovembcrT, - ~ ~ .. 19. 79.t.ha t."it9o,.ulif.1'e. accep table t.o fi.le.the a t. t.4. 9. I. 8. wo c .,, s ach. ed re ort ~ ~ .ber.5,;.1979 cyen.though Technical. Specification W-di;rfe - ' e '- f;, _4E-y;~_'*_- submit ta1.,,by.' Koves.b' r. 2, 1979. J e .-. J. -. . _. _-. _w.. r,... i '" ile'hM~ciIcTude'~dTh'at Technical" Specifications' 5.'5.~I 'and '5~~7TI' LWhe'un 6 f.]i ".. ';yldatM 'Jth'r(s'p_ect to the desig.n' and installatipn. ~o.f. a_jsgaJ13[r{$ngige v of ~thi~i~efsidfc"' pips reatrainta at '. Trojan.. At this. tice'. We, da_ not McIlhve . [,. "tha~ti; a*1'icTns'e aiEn' ment will be.neesssary since ' all 'saf'etir ElitgC@pe d .r ,,.. f'.t ' -,- su.ppor. ts and ~ restrai. n.ts installed.i..n. bl.ock walls.s.im_i.l. a__r.~to th.e_n.o.n_e_tt_o- ~ ~ . _. which__S. A _8)_isJC.tAched will be evaluated, the evaluation resul.ts;,wil.1. _ i.,*. ' __. be 'repor_ tedTf4 'aciiordance with your '. letter ' dated October' 2 2';. IY7C.~i}""-' ~_ ' C Go_odwin, Jr. eanf necessary mod.ifications or.tepairs.w .__be p.qr _ ~ a n.- " ',,,. '., '. <.f. o r,m..e d,. A.-. relimin.a.ry schedule of ~our ~ planned inV. estilgMifensW._odf -. u. ~-._-- j

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