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@y Docket Nos.: 50-440
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and 50-441 MEMORANDUM FOR: ELP 6,mdDirector, Division of Proie:t and Resident erogroms Eeilon III FROM:
D. G. Eisenhut, Director, Division of Licensing, NRR
' Sti!JEC'-
M T!JNMENT VE5SEL WELDS NOT IL STRIC7 COMPLIANCE WITH FSAR COMMITMEhT5 - PERRY NUCLEAR POWER PLANT (UNITS 1 6 2)
Your memorandum dated April 1,1983, same subject, requested NRR assistance in the resolution of the Cleveland Electric Illuminating Company (CEI) deviation from FSAR commitments for the Perry containment vessel design.
You advised that, as a result of Region III inspection findings, CEI conducted a re-review of previously accepted containment steel shell weld radiographs which determined that many of these radiographs were, in fact, rejectable.
Since NRR was then in the process of evaluating the use of concrete in the containment annulus as a strength-bearing structure (i.e.
to reduce stresses in.the containment vessel due to safety-relief valve actuations), you requested that NRR assess the technical and safety aspects of CEI's proposed deviation to the ASME Code requirements and their request to disposition in the welds in question, "use-as-is."
Attached, is a letter recently sent to CEI, providing the NRR staff's evaluation findings on the containment steel shell welds in question, and the annulus concrete fill design modification.
It concludes that the ASME Code deviations proposed for both these items are acceptable.
We propose t r docur ent tm sitfs fir.cings ir, Perry SER Supplpent No. 4 (NUREG-0857) to be issuec in hcvember 1983.
It should be noted that the staff's accep-tance of deviations to the ASME Code requirements for the deficient welds only pertains to the lower first four course circumferential welds, from the besenat, for both Units I and 2, which are inaccessible to repair due to completion of subsegaent construction work.
CEI has committed to repair all other questionable containment shell welds which Region III should continue to pursue with CEI in the resolution of its 1C CFR 50.55(e) action in this mhtter,
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We appreciated the opportunity to be of assistance in addressittg the l
- containment vessel weld issue.
If there are any questions concer.ning the l
.ettached evaluation findings, please have them directed to the ferry Projec
.. Manager (John J. Stefano). Mr. Stefano may be reached by FTS at 8-492-7037.
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Division 6f Licensing Office of Nuclear Re.ector Regul6tior
Attachment:
As stated cc w/ attachment:
J. G. Keppler, Reg. 111
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J. Konklin, Reg. 111 D. Danielson, Reg. 111.
W. Little, Reg. 111 V. Ward, Reg. 111 P. Pelke, Reg. 111 M. Gildner, Res insp. (Perry)
J. M. Taylor, DQASIP/01E E. L. Jordan, DEPER/01E R. Wessman, AD/SA, NRR
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UNa TE D STATES 1
1 NUCLEAR REGULATORY COMMISSION
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o SEP 211983 4
..ket Hos.:
50-440/441 Mr. Murray R. Edelman Vice President - Nuclear Group
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.The C1.eyeland. Electric 111uminating Company.
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P. O.. Box 5000 CleveTend, Ohio 44101
Dear 'Mr. Edelman:
Subject:
Acceptability of the Containment Steel Shell Weld Deficiencies and the Containment Annulus Concrete Fill Desien Modification for the Perry Nuclear Power Plant (Units 1 and 2)
The NRC staff has completed its review of the containment steel shell. weld deficiencies addressed in your letters dated May 31, 1983 and June 22,, 1983. 'It,
was requested that the staff accept your proposal not to require the repair of the weld flaws in the lower first four circumfer' ntial welcments of the steel e
shell, inaccessible for repair beceuse of subsequent construction work, based on the technical justification provided is your submittels. The staff has also cccietec its review of the containment cnnulus concrete fill desien nodification
. ycu proposed for reducing stresses in Ilfe containment structure due to safety-
-eif ef valve actuation, addressed in your letter deted April 25, 1983.
.ne staff has reviewed these submittels and finds that the design, analyses, materials and construction aspects of the containment steel shell weld defi-ciencies, the containment annulus concrete fill desien, end the deviations to the MME Code preposed for both these areas, are acceptable. 'Ine analysis per-formed by Aptech Engineerinc Services, Inc. on your behalf is considered to be quite conservative and demonstrates that General Design Criterion 51 would be met without repairing the weld flaws.
The staff finds that the containment annulus concrete fill design and deviations to the ASME Code requirements proposed would raet the intent cf the Code anc the applicabie provisions of the NRC Standard Eevie.s Finn (NURE3-C, Secticr. :.E.1) Enclosed are the staff's specific tecnni-cal evaluation, findings, and conclusions with respect to these areas, which we prcpcse to include in the next SER supplement to be issued in November 1983.
Sincerel,
((2%., dL B./J.Youngbood, Chief Ljtefsing B anch No.1 Division o, Licensinc
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Enclosure:
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See next page
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Mr. Murray R. Edelmar j
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Vice Presicent, Nu: lear Group The :leveland Electri Illumina:in; Company g-
. 0. 5:x 5000 leve7.and, Ohio 44101
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ec: ' Jay Silberg, Esc.
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Shaw, Pittman, Fo:ts & Trowbrioge i
4800 M Street, H. W.
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.fashington,'D. C.
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- Donald H. Hauser-, Esq.
The Cleveland Electric-111uminatine Company l-P. O. Box 5000 Cleveland, 0hi o '44101
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..esident Inspe: or'.s Office
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- 5. N.' clear ReE'.'.itory Commissior.
Farriy at Center Rcad '
Perry, Ohio 44051' U. S. Nuclear-Regulatory Cc missTo,n
'Mr. James G. Keppler, Regional Admin.istrator, Region III s
??E Ecosevelt Road Gier. Ellyn, Illinois 60137 D:nald T. Ezzone, Esq.
Assistant Prosecutinc Attorney 10E Main Stree:-
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Lake Ccunty Administration Center
- Painesville,. 0hio 44077' Ms. Sue'Hiatt DCRE Interim Representative
.E275 Munson Mer.t:r, Ohit 44050 Terry J. Lod;e, Esq.
McCormick, Pommeran: & Lodge E24 National Sank Eviiding sune c.s,.,
r.s-. a n.t.ce.
0;hn G. Cardinal, Esq.
Fr:se:Ufing A:terney Asn:acult Coun:y : urthouse defferson, Ohio 44047 r-l 3
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": Enclosure NRC STAFF EVALUATION t
OF
.c CONTAINMENT STEEL SHELL WELD FLAWS I
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-A e PRDPOSED ANNULUS CONCRETE FILL
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DESIGN MODIFICATION PERRY NUCLEAR POWER PLANT (UNITS 1 AND 2)
In Set: ion 3.6.2 of SER Supplement No. 3 ( April 19E3), the staff indic6ted that it was in the process of evaluating": (a) weld deficiencies located in the con-tEinre-steel shell (in the region of the suppression poo.1 area) found bv. re-radiog-sphy of the welds; and (b) the' placement of concrete in 'the annulu's
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6djacert to the suppression pool area.
The purpose of the annulus concrete is to recute stresses in the contaigment vessel due to vibration caused by safety-relief valve actuatiors.
e The stiff hes since completed its review of these items, the results of which are crisented below.
Beck;r:urd The fi-st iter, containment steel shell weld flaws, relates to the commitment nece by the applicant in Section 3.6.2 of the Perry FSAR which states that the sitel con:tinment structure will be designed and built in accordance with the re;uirements of ASME Code,Section III, Subsesction NE.
However, this comc.itrent was not fully met by the applicant because of the fact that several radiog Ephs taler cf the welts, now inaccessible due to ecmcletion of sub-sec e ; ccrs;ruc;ict wcrk, cere founc' nc: :t met: :nc ASME Code rec.iremer:s 1
per:Ei.ing c implemen:E: ion cf E cost effective prcgram Of re-rEciogr5pning end or repairing the flawed welos.
As an alternative solution, the applicant perfer ed a f racture f atigue analysis of the ineccessible flawed welds, and rec es ed.F1: de'ia:ic-s to :he AS"E Code recuirerents concerning radiogrt;hy or re:ti-ce accepted by the stEff on :ne resui s of their f racture fE igue EnEly!'s.
Tne se:c-c i;er, cesign aceovacy of the conteinmen; annuius concrete fill, pertei s to :ne at erial testing procedures used for the annulus concrete constr;ction.
Originally, there was a five (5) foot wide annulus between the s:te'. cc. Einrent vessel and the shielding building for the entire contEin-ren: rii;h.
However, with the consideration of safety-relief valve (SRV) vibra;;ry 1 cads for the EWR Mark III containment cesign, it became ne:essary
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to fill this annulus with reinforced concrete fo'r a heicnt of:b3f t-6in. above the top of the foundation mat (basement) in order to dampen viFratory loads iriuted within the containment vessel due to SRV actuations. The applicant
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asiured, in his analysis cf the annulus honcrete, a composite action of the st~ eel vessel, the annulus concrete end th'e thielding building to resist the inereased loads due to SRY actuations.
Furthermore, the staff questioned the appropriateness _ of the material testing procedures developed for the annulus concrete which also required resolution by the applicant.
Fo;;ceinc, is the staff's evaluation of these two items, its conclusions, anc t.he techr.ical basis for the conclusions rea:ned.
Deficiency of the Containter.: Steel Shell Welds The location of the questionable iniccessible steel shel1 weld flaws is in the 1: west weid courses of the containment vessel for both Ferry Units 1 anc' 2.
(i.e...the first four circumferential welds from the steel sheli/basema:
h, ir:erface).
Tnese welcs were fabrihated by Newport News Industrial Corpora-tier (NN~C), and were ini icily accepted based on a review cf their radio-gra:ns by NN 0 and the Authorized Nu~ clear Inspector (an inspector retainec ty tr,e applicant to perferr independent inspections for compliance with pipir; and vessel codes).
Tne +elcs were made in the 1976-1952 time period, and vere radiographed snor:1y af ter they were completed.
The radiographs vere re-reviewec in early 19E2 as the basis for continued acceptance of the welcs, when the ASME-require: macnetic particle inspettichs were found to have not been performed following scre repair welding.
This follow-up review raised questions about pt:ential defects or indications (flaws) in some racic-grepns.
Ey letters cated May 31,19E3 and June 22, 1983, the applicant provided a technical re: ort for supportinc and justifying his request for staff ecceptance of the
'i a..t :..eits with:ut rac air e r re-rac'iography.
The te:nnical reocrt, which was comrissi.cnet f rcm Ap;ech Engineering Services, Inc. ( Aptech) by the applicant, oresents the results of a fatigue and fracture mechanics analysis based on the flaw
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sizes, materials, preperties anc cperating conditions of the welds in question,
- efittin; f racture ;ef t rnEnte; i.e., if the flaws cresent would prevent cut:Ce failere er cause a rapicly propecatinc fracture.
Ap;ech chara::erirec
- he .aws by en ele:;r:ni: erhartenent technicue to c'efine their exten: (sire),
the tyoe tf flew (la:L :f fusion, cra:L, slac inclusions, ocrosity), and their a p;r:;ria:e c'epin.
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apprc>.ima: ion cf fiaw cepth by eie:tronic cata processing is viewed by :ne staff as a guide or aid in making judgments as to 9
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flaw depth, at the present time.
This technique is acceptable as an alternative to repeated radiography,provided t_ hat thg griginti productjort. radiographs meet minimum specifications as to image quality." Based'on the staff.'s experience with other original production radiographs, the Dse of computer-enhancement has provided assurances as to the actual width and length of weld tiaws; however, further demonstrated eccuracy of this i technique (for flew depth measurement.)t needed before it becoses e stardard
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\\ The stresses that thede' flaws would be' subljected to over the life of the structure,were characterized as to magnitude, direction, and frequency, for both applied and residual stresses.
The ferritic steels used in the containment shell were characterized as to fatigue crack growth by review of other date for the same materials.
Upper bound conservative crack growth rates were used when caluclating crack growth, includin; existing fracture toughness data for the weld metal (Charpy V-nctch va l u e s c f - 20F c r - 3,0 F ).
Tne icnest value cf mcre tha? 3D electrede icts, selected to be representative of the electroces used in f abricating the con:Ein-ment shell, was used as the basis for calculating fractu.re toughngss.
- Values, for base metal toughness, although not relevant to this situation, as all except ene of the flews were found in the welds (i.e. as opposed to thE base metal or t
heat-affected zone), were also assigned a fracture teuchness value on a con-I servative basis.
The fatigue crack growth analysis, and the linear elastic i
fracture rechanics ar.alysis, were performed es specified in ASME Ccde,Section XI.
Ccnservative essum;;iens were died in performing these analyses in :ht the flaws were assured :c be cracks throuch to the surface of the weld (
.e. surface cracks reiner than the internal / cracks), and the appliec icads were assumed to ec perpencicularly to the flaws.
Eased on its review cf the Aptech repcrt, the staff finds that the analyses and technicues performed to assess the effects of the flawed welds were quite ccnservative and demonstrate wha General Desigr Criterion Ei, " Fracture Prevention of Centain en: Pressure Boundary," woulc be ne; without repairing the flaws in the inaccessible weld courses of the containment shell.
The entlyses convincingly show that the flaws will have virtually no growth under l
the c;erating loads for which the shell was designed, anc that the steel riterials used in the ccniainrer pressure bcuriary have adecua:e toughness sucn :ha; a li ge thrcugn-nickness flaw wcuic r.c cause a ra;idiy ;rcea;5;in; i
fracture.
Therefore, the staff accepts the applican;'s proposal to leave the flaws in the containnent shell welds as is, anc not perform any additional recair c.f these weids.
The ccr.tair. ment shell will net be strenchened s';nificantly by re;5 iring the weics as they are sucn a stali percen:Spe cf te e waii thickness.
In f act, there would be risks in makin; weic' repairs cue tc the cistortions induced and high restraint cf the joint figura; ions.
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acdi;icr,, int s;aff celieves tr.a recair cf :ne weids wili not si;rifican:ly 1
increase the health and safety cf the public, and accordingly,_the effer; I
(time and cost) of making repairs is not justified or recuired 6
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r-Annuits Centrete Fili Desien Modification l.
Acetaa:y of Annuius. Concrete Analysis Mathtd? and Results-The staff has reviewed the applicant's annulus concrete analysis method, and has ais: evaluated the analytical results submitted by letter 4_ated April 25, 1953.
A finite element method was used\\to analyze the response.cf the inter-fate bet een the containment vessel, shielding builcint, the foundation met (bisemat), and the annulus concrete.
The structural modelling methods, and the computer codes used have been reviewed for use in previous case applica-tions, and therefore, are judged adequate and acceptable.
The analysis results and the technical discussions provided by the applicant has allowed the staff to conclude the following:
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ine ar.ntius con: rete and ::n:-ete shieldin; bu.ildinc shovic att together as o.onolithic con: rete.
(b)
The steel containment vess,el will adequately be anchorec by bon (
and reinforcement in the ennulus cpncrete at.the embedded circum-ferential stiffeners.
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The shear key provided at(the basemat cf the concrete shielding bu;iding shculd adecuatelypresist the applied transverse snea.
(d)
Shear and normhl stresses developed at the shielding building / annulus con: rete interface assures tnat cebounding of the interface would not cenerally occur, except at a very localized region near the base cf tne annuius.
Such localizec cebondinc should not affect the intecrity of the structures analyzec.
(e) The accitional stiffness provided by the annulus concrete is the main reason for a substantial reduction in the acceleration response of the containment vessel, and a frequency shift with respect to the location of peak response.
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- ' tre A-.uius Con:vete The eenuius concrete design is judged to have met the requirements of Article CC-3C:0 of the ASME Code, Section 111, Division 2, and ccmplies with the
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- . si: s ci !CFEG-0E00, Section 3.E.1 with the exception cf the allowable ta :e.t:ai shear stress resistance in the annuius con: rete.
The raximur cal' 'a e: tancer.tial shear stress in the annuius concrete is 83 :si, which under aEntrmai/ extreme environrental ccncitions, based on Article occu-!
CC-3:22.5.1 (a), cf the ASME Coce,Section III.
However, for the 2::vai reinferce-ment providec in the annulus concrete, the allowable tancential shear stress is 107 psi, which is greater than the computed stress of 87 psi,' and exceeds the l
correspending allowable stress of 60 psi specified in Section 3.E.1-II.fa in S
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ficnetheless, the applicant has provided the followi.ng justification for this ceviation, and indio3tet itet,.no inclined reinforce-ment in the annulus concrete would be used:
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(a)
The ennulus concrete design for tangential shear streir conforms
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to the recuirements of the A58E Code,Section III, Div~ision 2,-
Recent research results indic$te that the shear allowables of the A Code are judged to be conservatively low when the actual magnitude
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of stresses in the orthogonal reinforcement in the annulus concrete are taken into consideration.
(b)
The annulus concrete is not truly a part of the typical concrete containment.
It is used in Perry just to provide additional stiff-ness and t cc:en vibrations in the steel certainment vessel induced by SRV actuc.tions.
Therefore, the applicant mair.tains that the i
ext"emely conservative allowable stress of 60 psi specified in fiUREG-0300 need not be strictly adhered to in.this appl.ication.
(c)
From test cata obtained fred the Portland Cesent Asso3iation, the safety factor computed for the tancential shear stress computed for the annulus concrete is 2i27 (180/53), which the applicant believes to be ade:;uate.
h The staff finds inat the applicant's propcsed annulus concrete cesign end justification sumarized above for deviations to the ASME Ccde and h'UREG-i OE00 in recard to allowable tangential, shear stress, is acceotable.
3.
Materials, Testinc and Construction Considerations (a)
Reinforcing Steel - with respect to purchasing, placinc and mechanical splicing of reinforced steel bars in the annuius concrete, the applicant indicated that safety-related Perry specifications for concrete and reinforcing steel was used without consideration of the ASME Code, Se:ticn III, Division 2 recuirements.
However, the a;pli: ant nas ind'ea:ed that the Auth:-i:ed 0: lear :r5:ect:r was use:
at the site to review all material certificaticn anc construction procedures to verify that the Perry specifications are fully complied with; and that the intent of the aforementioned ASME Code provisions related si~~crcing steel and rechanical solices a-e generally met, his been assu ed.
The toolicant further stated that the cost to remove and repla:e the reinforcing steel in the annulus to comply fully with tne ASME Cc:e provisions will be excessive and w'll net significantly
'mprove safety.
~(b)
Concrete Supply and Placement - the applicant stated that, with respect 1 the supply of con: rete, its Specification SP-14 has been revisec to reet all appliceble ASME Code,Section III, Division 2 recuirenents.
The applicant also previdec a comparison of pertinent t -
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ASME Code provisions to tness of Spt.cifiestion, SP-14.
Scecification SF-14 meets and exceeds tne correspondin;- ASME Code Section III, Division 2 requirement.
Tne applicant further stated thaf'its site organization will continue to be responsible tct operate tni concrete 2.. batch plant, even though the ASME Code reovires th!t a se5ffate con-
'. tractor shall contract the batchin'g plant.
The applicant maintains"
~i-that no improvement in concrete qualit,y can be achieved by following the
- ASME Code in this regard; in fact some reductions in concrete quality could occur if. the contractor were required to control and operate the batch plent for the annulus concrete.
The staff has reviewed the applicant's justification for this deviation from the ASME Code requirement with respect to actininstrative control of the concrete batching plant, anc cencludes that tne deviatior is accepteble, since the ove eil Code inter.;
is. met by the ac;licant, anc actitional irortvement'ir Concrete cuality would be achievec through his tirect control of the batching plant for the rather small amount of concrete to be mixed for this annulus fill.
o' In view of the discussion and the te'bbnical justification delintated by the erolicant above, the staff concludes that both the containment steel shell weld ceficiencies and the various oeviat, ions to the annulus concrete cesign
.:difications fre-the ASME Code reg;the Code anc t?UREG-0E00 wiii be met irements end.the provisic.s cf tiUREG-0EDD, are acceptable, since the. intents ofe Further, the staff cencludes that the annulus concrete shou ac. maintain its structural integrity, and perform its safety functions when subjected to acplicable crerating icad conditions.
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