IR 05000280/1991037
| ML18153D204 | |
| Person / Time | |
|---|---|
| Site: | Surry, North Anna  |
| Issue date: | 12/29/1992 |
| From: | Richardson J Office of Nuclear Reactor Regulation |
| To: | Lainas G Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML18153B357 | List: |
| References | |
| NUDOCS 9212300251 | |
| Download: ML18153D204 (6) | |
Text
MEMORANDUM FOR:
FROM:
SUBJECT:
1.0 BACKGROUND UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. Z0SM A TTACHMENi DEc 2 Gus C. Lainas, Assistant Director far Region II Reactors Division of Reactor Projects - I/II James E. Richardson, Director Division of Engineering NRR POSITION REGARDING VIRGINIA ELECTRIC POWER COMPANY INTERPRETATION OF ASME SECTION XI AND THE RELIEF REQUEST PROCESS
On February 3, 1992,.the NR'c issued a Notte, of Violation (NOV), for a violation identified in Inspection Report 50-280,.281/91-37, to Virginia Electric and Power Caap&ny (the licensee or VEPCO) against their Surry Nuclear Power Station. This violation was based on a failure of the licensee ta request relief froa the requirtt1ents of the ASME Code,Section XI, in accordance with 10 CFR 50.SS The violation concerned a leak in a socket weld Joint in I Class Z pipe for the letdown systea. Tht leakage was first noticed when unidentified leakage started to increase but was still within the Technical Specification (TS) 11att of 1.0 gpa. Entries were made into the cantain111ent and the leakage was noted 1s COIiing froa a defective socket weld joint. The licensee atteapted to isolate the leak but, because of seat leakage through the isolation valve, was unsuccessful. Further action was needed to isolate the v1lv1 that involved entry into a high r1di1tian area and additional planning. Stnc1 the leak was well within the TS 11aits, the licensee placid the sectiOft of piping back in service unttl actions were formulated and coaplet1 to aake repairs. This particular condition was identified by the Resident Inspector afterward and brought up far discussion with both the Region incl NRR technical staffs. Both indicated that return of the piping to t111POr1ry operattonal status, without aaking any repairs or requesting IIIC relief, COftStituted a violation on the part of the license The licens.. responded to the notice of violation by letter dated February 28, 199 In its letter, the ltc1ns1e dented the viol1t1on, citing their interpretation of the ASME S9Ct1on XI Cod&, the Surry TS, and the Standard TSs for Westinghouse PWRs, NUREG-0452, Revision 4. The licensee's arguments were supplemented by ASME Section XI Code C0111itte1 Inquiry INtl-017, dated September 10, 199 The question to the ASME was:
- 0o the provisions of Section XI, IWA-5250 apply to leakage found at t1.. s other than during a systea pressure test?* Th* reply: *No.* Paragraph IWA-5250 concerns
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corrective actions to bl taken upon the discovery of leakage dur/ing ;tKe
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canduct of syst* pressure test _.11~~
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I G. Lalnas 2 scuss10N The crux of the licensee's position was that operational leakage falls under the control of the station's TSs and not the ASME Code as stated in Generic Letter (GL) 91-18. A discussion of this position was presented to the NRC staff at the NRC/Virginia Power Counterparts Meeting conducted on September 24, 1992, at the licensees headquarters in Rich11and, Virgini The licensee interprets the scope of ASME Section XI to be limited to over-haul/ISi inspection activitie In their view,Section XI provides rules for:
exaaination and testing of c~onents;
timing the exillinat1ons and tests; and
controlling the repair/replaceMnt proces The view that Section XI does not apply to operational leakage was bolstered by the Code Co1111ittee inqY1ry cited ~bov With respect to the rep1ir/replace11ent rules, the licensee believes tut
repair/replac... nt actions are required to correct d*fects identified by Section* XI ex111in1tions or tests; and
repair/replac... nt action undertaken by the plant 1s required to 111et Section XI regardless of how tdenttfte The second point 111kes a fine distinction involving the tiatng of a repair/
repl aceaent. Th* tiatng for execution of a repair/replaceMnt h:, dependent upon how a defect ts discovered. Should a pressure boundary deficiency be noted during an ASME test, the licensee holds that 2 options exist:,.
repair or replace per Section XI; or,...
request relieJ fl'Oll Section XI per 10 CFR 50.55 However, should a defictency be tdentiftld as part of non11l plant operation or maintenance acttvittes, the license, 111intatns th&\\ a different approach applies:
cllteratne and tapl-nt actions required by TSs;
tf TSs allow continued operation without tlllldtate action to repatr/rtplace; th111
deterat.. the pr1cttc1ltty of p@rfon!!l1ng I S@Ct1on XI repatr/replac... nt; and then
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repair per Section XI, or, operate with leakage, or,
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request reltef for non-Cod* repai Note that the option of operating with leakage does not involve a request for relief. The option to operate with leakage ts dependent upon the outcome of the practicality deten1ination for making a Code repair. This decistg.n-log..i.C----~.
provides aaxi11Ua operational flexibility for the ltcense.l
e e
G. Latnas
During the ti.. the above outlined events were ongoing, a related kind of incident aros By letters dated August 26, and Septlllber 2, 1992, the
licensee requested relief frOII the Code repair requ1reaents for a high energy Class 3 steaa condensate line at North Anna Unit The licensee found a pinhole steam leak in a 3-inch NPS drain line connected to the main steam syste*. The affected pipe was part of the *ain ste111 stop valves before and after seat drains. The leak was.attributed to erosio The leak was judged unisolable because enough seat leakage was thought to exist to *aka a weld.
repair iinpractical. A Code repair would require a unit outage. A temporary repair, consisting of an engineered mechanical claap was proposed by the licensee. Although teaporary repairs of this kind are normally discouraged for high energy systems, this *proposal.was approve One of the aitigating circuastances allowing this 1111asure was the fact that the systea could be effectively depressurtzed prior to attachment of the ~l111 The duration ta gain final written apprQval for this teaporary repair was also a conc;rn for the 11e@nse1, and was a subject for discussion at the
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counterparts aeettn *
3.o STAFF EVALUATION The staff has reviewed the above outlined events and discussion presented by Virginia Power Corporation in regards to actions to be taken with respect to th~ relief req~est process in relation to ASME S~ctton X * *
The license, has adopted an interpretation of the scope of ASME Section XI which, in the staffs' review, ts far too narrow. Apparently this position is bolstered by the lllbiguous Code C0111ttte1 tnt1rpr1t1tton whtch states that paragraph IWA-5250 does not apply to l1akag1 d1scoverld during noraal.
operation. The staff has yet to d1ctde if thts interpretation ts in the best interests of safet When a through-wall le\\i occurs tn ASNE Code class ptpfng, the licensee must promptly deteratne the operabtltty of the piping. For piping, this ts done by assessing its struci~ral 1ntegrtty. Thts assess.. nt aay be accoaplished under the flaw evaluation rules*of on, of several Code sections or Code case However, the Code does not peratt flaws greater than 751 through-wall to be evaluated. 10 CFR 50.S1a(g)(4) states: *Throughout th, s1rvtc1 life of a boiling or,ressur1zld water-cooled nuclear power fac111ty, caaponents (including....,.rt,) llllltcll are classtf11d as ASNE Code Class 1, Class 2, and Class sh~1111181 _tt.a ~tr.iifits, iXeipt th1 d1sign and access provisions and preservtce ex111tnatton reqi1reaents, set forth 1n Section XI of editions of the ASME Boiler and Pressure Vessel Cod* and Addenda that becOIII effective subsequent to editions specified 1n paragraphs (g)(2) and (g)(3) of this section and are incorporated by r1f1renc1 tn paragraph (b) of thts section, to the extent practical wtthtn the ltattattons of design, ge0111try and aaterials of construction of the coapon1nts.* Stnc, the Code flaw 1valuatton criteria ar, not sattsf11d, by the evidence of a leakage, and, therefore, the rl(Julat1on ts not.. t; hence, the coaponent aust be considered inoperable and the appropriate systea LCO aust be entered. This guidance ts also contained in GL 91-18 on degraded cond1ttons and operabilit G. Lainas
In the case of IIOderate energy ASME Code Class 3 piping that is leaking, the alternative rules of Generic Letter 90-05 May be applie An evaluation in accordance with the methods and criteria in the GL 1111y be conducted by the licensee to deten111ne 1f the pipe involved can be considered degraded but operable as stated in GL 91-1 If the piping can be considered degraded but operable by the licensee, a written request for relief should be prepared and sent to the NRC within 30 day In the absence of the evaluation in accordance with GL 90-05, the pipe is inoperabl Application of the generic letter 1s clearly and unlllbiguously stated in the first paragraph of page 1 in the introduction section in GL 90-05: *The staff continues to find temporary non-Code repairs of Code Class 1, 2, and 3 piping unacceptable without specific written relief granted by the NR However, this generic letter provides guidance that will be considered by the staff in evaluating relief requests subllitted by licensees for.temporary non-Code repairs of Code Class 3 piping.* This position originates froa and is consistent with 10 CFR S0.55~(g)(6)(1) \\llh1ch states: *Th* CG1111sston w11l evaluate deterainations under paragraph (g)(5) of this section that Code require1111nts are 1apractical. The Cot11ission ~Y grant relief and aay iapase such alternate requireaents as it detera1nes ts authorized by law and will not endanger life or property or the.c01110n defence and security and 1s otherwise in the public interest giving due consideration to the burden upon the licensee that could result 1f the requ1r... nts were iaposld on the facility.*
There is no basis for the failure by any licensee to request relief when the provisions of 10 CFR 50.551 are considered. It 1s plainly evident that a licensee is obligated to request relief when coapliance with the regulations or the relevant sections of the ASME Code (that were incorporated by_reference as part of the reguJ1t1ons) 1s tn.doubt.. when th*. plant. ts.;p,rating. * *
The staff finds additional *deftci1nct1s with *respect to the VEPCO! s interpretation of their existing plant Technical Specifications (TS). The staff intends to address the TS issue tn a separate correspondence. It should be pointed out that the staff expects VEPCO will... t the regulations whether or not a question exists on TS interpretation There aay be instances.e..re a flaw evaluation ts either infeasible or i11111aterial die to tndtvtdual coaponent-specific circuastances such as peculiar geometries. 11--tllos* cases the regulatory issue ts overall plant safet The leaking NS valwe drain ltne at North Anna provides a good 1xaaple. A flaw evaluation..snot posstbl* due to an tn1btltty to 111asur1 the ~all thinning at the flaw loc1tt11 St11e1 structural integrity was indeterainate, the operab111ty determtn&ttn =:111 hav; to assu-that th&* 1 hili was d1graded and inoperable. Consequently, the safety significance of the existing leak and/or a postulated pipe rupture bec1111 a deteratntng factor in the JCO evaluatio By licensee evaluation, the significance of a postulated break was aini~al due to the location of the eroded pipe and the fact that tt could be isolated if it failed. Furtheraore, the line could r.._in tsolatld aost of the time, as it was only required to be in operation for periodic blowdowns-once a shif G. Lainas
In order to alleviate the structural integrity question, the licensee proposed that i load blaring cllllP be installed at the leik location. Because so111 amount of ao1sture r1a1ined in the line ifter isolation, i Code repair by welding wu considered risky, in the plant staff's opinio Due to the ability to isolate the line, there was no risk to personnel during installition of the proposed claap. Because of the short durations thit the line WiS in operation, and the ibility to isolate it and aaintain safety, the stiff found sufficient bases to approve the JCO and the non-Code repair relief request; ilthough, not under the provisions of GL 90-0 With respect to the licensee's coaplaint concerning the duration to obtain approval/dental of a relief request, the staff concurs that there is roOII for improvemen The staff 1s aware of this concern and w111 endeavor to aake improvements in this ire As an adjunct to the specific incident mentioned, the... staff position on pipe leakage and relief requests 111y be instructiv An inservtce leak 1n Code Cliss l, 2 ind high energy Class 3 syst.. s 1s generally unacceptable and only considered on I case by case basts. For these situations, relief aust bl explored through direct conversation with th1*1ppropriate technical staff during the syst.. LCO ti.. fr111 Once a licensee has contacted the staff and has obtained concurrence with their bases that the caaponent ts degradld but operable or that a safety 1rg11111nt can be provided to Justify operation, the staff consid1rs the relief request process to be in progr1ss. Th* affected component is either tentatively considered degraded but operable or the staff has tentatively agreed with the 11c1nse1s' JCO. Obviously, the ability of the staff to judge these situations tr, a tt.. ly 11ann1r 1s related tcLthe thoroughness and thoughtfuln1ss of the lic1ns1es' evaluations of the flaw and the systea consequences. r1.. 1y subllittal of the written relief request and supporting docu.. nts 1s necessary for th.. staff"'s written safety analysi Should the subsequent staff review of the subllitted aatertal be negative, the licensee returns to the provisions of the syst.. LC Clarification of staff position r191rding appltcatton of Generic Letter 90-05 is included in the attachld letter to H. Berkow, dated Novlllber 16, 199 Enclosu":
As Statid
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Technical Contacts:
R. He~nn 504-2768 G. Hornseth 504-2756 Crfgina Sianecf bv J1111s E. Ric~aritsbn, Director Division of Engin11ring SEE NEXT J!AGtJQ\\t DJSTR~ION ArlJ CONCURRENCES
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