ML18153D175
| ML18153D175 | |
| Person / Time | |
|---|---|
| Site: | Surry, Crystal River  |
| Issue date: | 11/16/1992 |
| From: | Strosnider J Office of Nuclear Reactor Regulation |
| To: | Berkow H Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML18153B357 | List: |
| References | |
| GL-90-05, GL-90-5, TAC-M83201, NUDOCS 9211190159 | |
| Download: ML18153D175 (4) | |
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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON. D.C. 211111 NOV l 6 1992 Docket No. 50-302 MEMORANDUM FOR:
Herbert N. Berkow, o;rector Project Oirectorat, 11-2 Division of R11ctor Projects FROM:
Jack Strosnider, Chief Materials and Ch1111ical Engineering Branch Division of Engineering ATTACHMENT
SUBJECT:
REVIEW OF FLORIDA POWER CORPORATION INTERPRETATION AND APPLICATION OF GENERIC LETTER 90-0S.
(TAC NO. M832~1)
By l1tt1r dated January 15, 1992, Florida Pow1r Corporation, the lic1ns1e, described an application of the provisions of G1n1rtc L1tt1r (GL) 90-05 with intentions for future similar actions based upon their int1rpr1tation of the
- guidance in the g1n1ric l1tt1r. The staff has reviewed the technical and non-technical aspects of the lic1ns11s confon1anc1 to the guidance of GL 90-05, and finds generally acceptable application of the technical provisions (engin11ring, operational) but takes exctption to the licens.. s*
inttrpretation and application of the ragulatory issues.
The specific application of the GL involved the discovery and teaporary rep1ir of a leak in a raw water (RV) servicts pipt. spool at Crystal River Unit 3 during 1991. This line is classified as a IIOderat, 1n1rgy ASME Code cl1ss 3 pipt. During unit operation a leak was discovered in a z* NPS pipe spool which is a branch connection off a 20 inch diaatter RV line. Visual examination deteratnecl the leak to be a through-wall pinhole, later verified to be due to a corrosion ptt at a holiday in the urethane ltntng of the pipe.
The licensee appears to have properly applied the technical gutdanct of the GL: impracticality det1r11inatton, root cause d1t1r11tnation, flaw characterization, flaw evaluation, structural integrity ass1ss.. nt, 1ugmented inspection, s1rvetll111Ct plan, app11cat1on of a reversible leak 11ait1ng measure and ft11111y, a Coclt qualtfted r1p1ir 2 months later during a mid-cycle outage.
B1caus1 of till ltrevtty of the letter, the staff could not verify tha validity of all the tedlfttcal ts1ue1, spectftcally the 1apracttca11ty dettrainatt,pn-~1'~
the fliw e1v1lu1t1c;; c;1cu1at10iii. Huwvir, t~ staff does not finC!/th9<~. /
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and reinspections.
The stopgap measure may become a part of the temporary repair, but its purpose is usually only for housekeeping reasons. Containing the leak is not required beyond reasons of housekeeping or system flow considerations or equipment flooding issues, except inside containment.
A leak limiting (or stopgap) m1asure has no structural significance beyond that necessary to resist the hydraulic pressure of the leak.
Leak limiting (or stopgap) measures may consist of a rubber patch and a hose clamp.
If the loss of flow is insignificant, the pipe may be left as is.
The real crux of GL 90-05 is 1n demonstrating structural stability at the flaw(s) and monitoring them to ensure that safe operating margins will be maintained until such time that a Coda repair can be made.
Should the analysis reveal unacceptable flaw size or growth (or other :dvcrs1 system impacts), an innediate unit shut-down and Code repair is required.
The staff position discourages application of haphazard, non-1ng1n11r1d *f1x1s* to.
operating syst.. s and m1n1aizts unnecessary challenges to plant 1quip.. nt and to plant personnel froa a ruptured pipe. Nott also that acceptance criteria
- for structural claaps with load blaring capability beyond that needed for hydraulic forces ar, outside the scop* of GL 90-05 and require staff evaluation on a cas, by case basts.
The position presented in this IIIIIIO ts consistent with that presented in a Task Interface Agre... nt, dated July 9, 1992, concerning similar issues at the Surry Power Plant and which received review and concurrence by OE and OGC.
GIIIIIII iaNd w.
Jack Strosnider, Chief Materials and Ch.. tcal Eng1ne,r1ng Branch D1v1s1on of Eng1nttr1ng Ttchnology DISTRIBUTION:
Central Files EMCB RF GHornsetll RHen11ann JStrosn1d1r
- SEE PREVIM CCIICUIIIENCE DE:EMCB Dl:EMCI.
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- RHermann 10/9/92 10/13/92 Ul"t'!':_:!.&!. D __:*_:*_*~_!_ '-,;Ul'I FILENAME: 1:\\HORNSETH\\LEAKS.FPC DE:EMCB ~ t JStrosnider ~ t 11/9 /92 "
Section XI by the NRC.
This ts clearly and unambiguously stated tn the first paragraph of page 1 of the introduction to GL 90-05:
NThe staff continues to find temporary non-code repairs of Code Class 1, 2, and 3 piping unacceptable without spe~ific w~itten relief granted by the NRC.
However, this generic letter prov1des gu1danc1 that will be considered by the NRC staff in evaluating relief requests submitted by licensees for temporary non-Code repairs of Code Class 3 piping.* This position originates from 10 CFR 50.55a(g)(6)(i) which states: *Tht Connissian will evaluate d1t1nninations under paragraph (g)(5) of this section that Cade requirements art impractical.
The Conmissian may grant rt11tf and may impose such alternate requirements as it detennints is authorized by law and will not endanger lift or property or the conmon d1f1nc1 and security and ts otherwise in the public tnt1r1st giving due consideration to the burden upon the lic1ns11 that could result if the requirements w1r1 imposed on the facility*.
Tht license* has not and cannot pravid! l basis for its fa11uri to request relief when the provisions of 10 CFR 50.SSa(g)(&)(i) art considered. It ts plainly evident that the ltc1ns11 ts obligated to request relief when compliance with the Regulations and the ASME Code is not continued when the plant is operating.
Clearly, the licensee was in v1alatton of 10 CFR 50.551 with respect to the tllllS)orary repair at Crystal R1vtr Untt 3. FurthtrllOrt, the licensee would be in violation in future cases if the proposed r1vtsion to the units' Repair and Replac... nt Prograa art carried out as stated on the last page of the licensees' letter: *Thts revision would docuaent FPC's intent to 111Ploy appropriate stopgap.. asures wttbpyt s11k1nq c*J11f far *1nor J11ks, Formal reJitf wiJJ b* sought only tn tbpsa cases wb*o
- Cod* c1a11r would not bt R*ctocntd 1t tb* 011t approprtat* opportyntty* c.. ph1sts idd<<IJ. under the provisions of the cited secttons of 10 CFR 50.5Sa and the guidance in GL 90-05, the staff ftnds the ltc1ns.. s* pos1t1on regarding when to request relief to be completely un1ccept1bl1.
In the area of techntcal concerns, the lic1ns11 co11111nts that so.. confusion exists w;th regard to appltcat1on of stopgap 1111sur1s while going through the relief process, and the appltcat1on of leak liatttng.. asur1s as part of the temporary l'lfl1P. TIie a,,ltcatton of stopgap 1111sur1s to reduce leakage is pennittld ~
that 1111119tne1rtng evaluation of the flawed pipe de110nstrat~
~safe operating 111rgtns exist. The stopgap.. asure must bt reversible.. 11 to allow l"lll0Vt1 tf required. The r1v1rs1b11 requ1r1111nt precludes..,su... s sucll 111Mldtng whtch 111y exacerbate the flaw (such as by d@stroy1ng ! p1pe 11n1ng) er any iiiehin1ea1 clii!Pint devices that would deform the piping.
The subsequent *tllll)Orary repatr* that follows tn the relttf process under GL 90-05 is really not so aucb a repatr, but a syst... ttc 1ngtn11r1ng evaluation of the flaw.
The steps include root cause analysts, flaw 1valuatton, operating syst.. 1ss1ssaents, augaented inspections, and pertodtc 11111ttoring
~--~-----------------------~---------i spec;fics of this technical analys;s to be a significant issue.
It appears that the licensee has a good grasp of the technical issues.
However the staff finds the licensees' regulatory interpretations and pos.itions in non-compliance with 10 CFR 50.SSa and contrary to the guidance provided in GL 90-
- 05.
When the through-wall leak occurred in ASHE Code class piping, the licensee should have requested relief from the requirements of 10 CFR 50.55a(g)(4):
H.
"Throughout the service life of a bo;ling or pressurized water-cooled nuclear power fac;11ty, components (including supports) which are classified as ASHE Code Class 1, Class 2, and Class 3 shall meet the r1quir1t111nts, except the design and access provisions and preservic1 ex111tnatton requirements, set forth in Section XI of editions of the ASHE Boiler and Pressure Vessel Code and Addenda that become effective subsequent to editions specified in paragraphs (g) (2) and (g) (3) of this section and are incorporated by reference in paragraph (b) of this section, to the extent practical within tht limitations of d;sign, g1om1try and materials of construction of the components.* Crystal River Unit 3 is currently required to meet the ASME Boiler and Pressure Vessel Code,Section XI, 1983 edition with the 1983 SWllllr addenda.
When a ltcensu finds a degraded coaponent. it 1111st proaptly det1r11ine its operabtltty. For piping. this ts done by assessing its structural integrity. For the 2* RV syst.. ptptng in question. allowable indication sizes for ferritic stul piping are specifttd in IWO/IVB-3000, "Acteptance Standards for Flaw Indications*. paragraph IVB-3514.Z. Table IWB-3514-1.
The through-wall flaw causing the leak is an indication with an a/t, exceeding 14.4; therefore. ASME structural integrity requir... nts are not sattsfttd and the c0111pOnent ts not satisfactory for conttnutd service. Using special analytical.1111thods, ASME XI and ASME XI Code cases peratt evaluation of both planar and *non-planar flaws to a maxillUII depth of about 75 I through-wall.
The staff recognized that these crit1rt11 aay be stringent and providld guidance in Gls 90-05 and 91-11 to provide relief for IIOderate energy Class 3 systeas.
In particular GL-11-11 allows IIOderate ene'ly ASNE Code Class 3 piping to be constdertcl d19radld but operable by the tcanstt tf th1 criteria in GL 90-05 are sat1sftecl. TIits allows the 11canstt tt.. to pr1p1r1 and subflit a relt1f without creating an urgent operab111ty sttuatton.
GL 90-05 spectffcally addresses the frequently encounterld flaws of the type seen tn RV or s1rvtc1 wat1r syst.. s 1n operating plants and provides for r!11ef under tliliPGrary~14lt1rn1tive analytical and acceptance criteria.
However. appltcatton of the &L (or any other t111PCJr1ryi non-Code ~~sur;)
requires spectftc re11ef froa the requtr... nts of 10 CFR 50.551 and ASME Code