REGULATORY 'ORMATION DISTRIBUTION SY M (RIDS)

ACCESSION NBR:8910260096 DOC.DATE: 84/10/05 NOTARIZED: No DOCKET 0FACIL:50 275 Diablo Canyon Nuclear Power'lantE Unjt li Pacific Ga 050002

50 323 Diablo Canyon Nuclear Power PlantE Unit 2E Pacific Ga &0323AUTH

BYNAME

AUTHOR AFFILIATIONSHIFFER,J AD, Pacific Gas 8 Electric Co.'RECIP,NAME RECIPIENT AFFILIATION

KNIGHTONE G ~ H ~ Licensing Br anch 3

SUBJECT: Forwards Procedur es I 59'Instruction for Evaluation ofLicensing Condition 7 Concernsi" 8 P-36'Nalkdown of'PipingDu> ing Hot,Functional i" in response to 840925 request forinfo r e piping 8 pipe support matters;

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05000275

05000323

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October 5, 1984

PGandE Letter No.: DCL-84-323

Mr. George M. Knighton, ChiefLicensing Branch No. 3Division of LicensingOffice of Nuclear Reactor RegulationU. S. Nuclear Regulatory CommissionWashington, D.C. 20555

Re: Docket No. 50-323Diablo Canyon Unit 2Piping and Pipe Supports Review Program and Status Report

Dear Mr. Knighton:

The enclosed material is provided in response to your September 25, 1984request for information regarding Unit 2 piping and pipe support matters. Therequest'specifically included Unit 2 efforts undertaken to address the sevenpiping and pipe support-related items defined in the Unit 1 LicenseCondition 2.C.( 11).

Kindly acknowledge receipt of this material on the enclosed copy of thisletter and return it in the enclosed addressed envelope.

Sincerely,

Enclosure

cc: H. E. SchierlingService List

841026009h 841005PDR ADOCK 05000275P 'DR

~ ~

PGandE Letter No.: DCL-84-323

ENCLOSUREDIABLO CANYON UNIT 2

PIPING AND PIPE SUPPORTS

I. SUMMARY OF UNIT 2 PIPING DESIGN PROGRAM

At the time of the initiation of the Design Verification Program in late 1981,the status of both engineering and construction for Unit 2 was different fromUnit 1. The Hosgri reevaluation and upgrading had been completed for Unit l.The Hosgri reevaluation and upgrading for Unit 2 had been completed only incertain specific areas requiring early completion, such as civil/structuralupgrades to the turbine building (buttresses). The Hosgri upgrading andengineering completion of the safety-related piping and pipe supports,including certain piping related programs for high energy line break andNRC IE Bulletins 79-02 and 79-14, had not been completed for Unit 2. In mostcases, the Hosgri work for piping and pipe supports had not yet been startedfor Unit 2. Also, certain engineering and construction work on Unit 2, suchas small bore pipe supports, had not been completed even for the previousseismic design conditions.

In completing the engineering, design, and construction of Unit 2, the basicdesign philosophy for the Diablo Canyon Nuclear Power Plant has been thatUnits 1 and 2: (a) remain as identical as practical; (b) conform toessentially the same licensing criteria; (c) are designed to the same criteriaby, generally, the same organization; and ( d) are built by essentially thesame contractors. The principal structures and systems of the two units areessentially the same with only minor, local differences. Consequently, thepiping arrangement is essentially the same for the two units.

Minor differences do exist in piping arrangement and pipe support design whichresult primarily from the "opposite hand" arrangement of Unit 2 with respectto Unit 1. These minor differences in piping design are necessary toaccommodate equipment which is identical to that furnished for Unit, 1 (samehand) for use in the opposite hand arrangement for Unit 2. Also, some pipinglayout differences resulted from construction time differences and experiencefrom the first unit, combined with minor layout changes to facilitateconstruction 'and improve access. Due to the rigorous analytical nature ofpiping design, these minor differences are sufficient to require a completeset of unique analyses, calculations, and pipe support designs for Unit 2.However, the same criteria, methodology, design process, and basic procedureswhich were employed for the Unit 1 review, verification, and modificationeffort were used for the analyses, calculations, and designs for Unit 2 piping.

Both units were designed in accordance with the same (}uality AssuranceProgram, the same Engi'neering Manual, and the same Project Procedures Manual,under the direction of a Project Management Team that manages and overseesboth units.

Additionally, the Project Engineers Instructions (PEIs), Design CriteriaMemoranda (DCM), and piping-related procedures are essentially the same for

0014s/uU22K

MINMFRINErRggp>

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both units. Differences in these documents are not associated with basiccriteria, methodology, or design process, but are primarily administrative andresult from the fact that Unit 2 is a plant under construction, whereas Unit 1

has an operating license and, thus, requires different processing of designwork through the plant operating staff.

Since, on Unit 2, Hosgri upgrading was required for the piping systems (whichincluded reanalysis of all Class I large and small bore piping), it wasdecided that the most efficient and effective approach would be to usecomputer analyses for all Glass I piping rather than a combination of computeranalyses and span tables as was used for Unit l.This was done for the following reasons:

o Fewer additional supports or modifications would be required since acomputer analysis need not be as conservative as a span table method

o Computer programs allowed for combining thermal and seismic loadinginto one analysis

o Greater familiarity of current computer analysis methods ( versus spantables) by engineers performing the upgrading

o Ease of incorporating current as-built walkdown dimensionalinformation into the design calculations and analyses of record

Additions and modifications to piping and pipe supports resulted primarilyfrom the Hosgri. upgrading as part of normal plant completion for Unit 2. Anychanges to procedures, requirements, or criteria made for Unit 1 inconjunction with IDVP, ITP, or NRG concerns were directly applied to Unit 2since the criteria, methodology, design process, and basic procedures are thesame for both units. Therefore, the IDVP, ITP, and NRC concerns on Unit 1 arebeing addressed in Unit 2 as part of the normal completion process, and theUnit 2 results are entirely consistent with Unit l.

0014s/0022K

II. APPLICATION OF THE UNIT 1 PIPING LICENSE CONDITION TO UNIT 2

License Condition 2.C.(ll) of Facility Operating License DPR-76 for DiabloCanyon Unit 1 was issued by USNRC "Order Modifying License" dated April 18,1984. It established seven license condition items concerning piping and pipesupports that were required to be met prior to issuance of a full powerlicense for Unit 1. These seven items are being addressed for Unit 2 asdiscussed in the following sections.

A. SMALL BORE SUPPORT REVIEW (License Condition Item 1)

"PGandE shall complete the review of all small bore piping supports which werereanalyzed and requalified by computer analysis. The review shall includeconsideration of the additional technical topics, as appropriate, contained inLicense Condition No. 7 below."

All calculations (357 total) involving Unit 1 small bore, seismic Category 1

pipe support frame structures analyzed by computer were reviewed for theproper use of the STRUDL program as well as for the appropriate attributes ofItem 7 of the License Condition.

All supports were found to be acceptable and no physical modifications wererequired. Three supports were mod>fied to reduce angle member spans eventhough test data verified the,acceptablility, of the original design.

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All small bore, seismic Category 1 pipe supports are being reviewed for theappropriate attributes of Item 7 of the License Condition. As established forUnit 1, these have been determined to be issues (a), (c), (d), and (e) of Item7. In addition, the calculations are being reviewed for general quality andacceptability, and to ensure that as-built conditions are appropriatelyreflected in the analysis. This review is being accomplished as part of thefinal as-built acceptance process for all small bore pipe supports.

Procedures and Criteria

Attachment 1 is Instruction I-59, "Instruction for the Evaluation ofLicensing Condition No. 7 Concerns - Diablo Canyon Units 1 and 2," whichdescribes the procedures and criteria employed for this review.

Results

The review of small bore, seismic Category 1 pipe supports for theappropriate attributes of Item 7 of the License Condition is currently inprogress and will be completed prior to fuel load. To date, this reviewhas been completed for approximately 50% of the small bore supports. The

0014s/0022K

total scope of this review involves approximately 4,000 small boresupports.

B. PROXIltATE RIGID SUPPORTS (License Condition Item 2)

"PGandE shall identify all cases in which rigid supports are placed in closeproximity to other rigid supports or anchors. For these cases PGandE shallconduct a program that assures loads shared between these adjacent supportsand anchors result in acceptable piping and support stresses. Upon completionof this effort, PGandE shall submit a report to the NRG Staff documenting theresults of the program;"

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Design Class 1 large bore and small bore piping isometrics were reviewed toidentify proximate rigid supports. A total of 150 supports were shimmed wherenecessary to satisfy the new proximity criteria agreed upon by PGandE and theNRG Staff.

2. ~i" 2 P

Design Class 1 large and small bore piping isometrics are being reviewed toidentify rigid supports located in close proximity to other rigid supports oranchors. The criteria for the applicable proximity distance and theprocedures for identifying, inspecting, and shimming as necessary are ~

identical to those used for the Unit 1 review. 'As a result of de'tail'eddiscussions with the NRG's technical audit team assigned to review this issue .

on Unit 1, final conservative criteria were established and agreed upon forthe'Unit 1'eview of this issue. These same criteria are being used for theUnit 2 review of rigid supports and snubbers in close proximity to other rigidsupports and to anchors (equipment nozzles, penetrations, and pipeanchors/decoupled branch connections). Criteria for both supports (LicenseCondition Item 3 covered in paragraph C of this report) are summarized asfollows:

b.

Snubbers and Rigids Next to Rigids

All snubbers and rigid supports on large bore piping locatedwithin five pipe diameters (5D) of a rigid support are reviewed toassure that: ( 1) the snubber would actuate when required or pipeand support qualification is demonstrated with the snubber removedfrom the analysis, and (2) the as-built gaps in the hot conditionwere 1/16-inch or less, or shimming is performed as required.Piping of 2-inch diameter and smaller is excluded from this review.

Snubbers and Rigids Next go Anchors

All snubbers and rigid supports on large bore piping within tenpipe diameters (10D) of an anchor are reviewed to assure that:

0014s/0022K

( 1) the snubber would actuate when required, or pipe and supportqualification is demonstrated with the snubber removed from theanalysis, and (2) the as-built gaps in the hot condition were1/16-inch or less, or shimming is performed as required. Forsmall bore piping (piping~ 2 inches in diameter), supporteffectiveness is considereZ for all snubbers and rigid restraintslocated within 10D of an anchor. The criteria are summarized inFigure l.

All Design Class 1 large and small bore piping isometric drawings arebeing reviewed to identify all support pairs located within the "closeproximity" criteria. The review is being performed and checked by pipingstress analysis engineers.

The identified support pairs are then inspected in the field and all gapsin the restrained direction are recorded. These inspections areperformed with the plant in the hot stand-by or equivalent condition.

The support gap measurements are reviewed to determine support shimmingrequirements to limit differential movement at proximity restraints to1/16-inch.

The drawings of those supports which are identified as requiring shimmingare revised to specify a clearance which will provide compliance withmaximum gap differential requirements. The supports are modified'ocomply with the drawings, and as-built drawings are prepared and issuedto Engineering. Engineering then reviews, the as-built drawings to verifyconstruction to engineering requirements.

ResuTts

The review of proximate rigid supports is currently in progress and willbe complete prior to fuel load. Based on the results of the review ofapproximately 8(C of the pertinent piping isometrics, 115 pairs ofproximate rigid supports have been identified for further review andpossible shimming as necessary. It is expected that Unit 2 will have

~ fewer proximity restraints requiring shimming than were required forUnit 1. This is primarily due to the later schedule for Unit 2 and theresulting fewer iterations and modifications throughout the designprocess.

0014s/UU22K

FIGURE 1

PROXIMITY CRITERIA FOR SUPPORT REVIEW

Support Pair LARGE BORE (DP 2") SlNLL BORE (D ~ 2")

Ri gi d-Ri gi d 5D N/A

Ri gi d-Anchor 10D 10D

Snubber-Rigid 5D N/A

Snubber-Anchor 10D 10D

0014s/OU22K - 6-

C. PROXINTE SNUBBERS (License Condition Item 3)

"PGandE shall identify all cases in which snubbers are placed in closeproximity to rigid supports and anchors. For these cases, utilizing snubberlock-up motion criteria acceptable to the Staff, PGandE shall demonstrate thatacceptable piping and piping support stresses are met. Upon completion ofthis effort, PGandE shall submit a report to the NRC Staff documenting theresults."

Design Class 1 large bore and small bore piping isometrics were reviewed toidentify proximate snubbers. A total of 81 large bore snubbers (no small boresnubbers) were so identified. All proximate snubbers were shown to eitherfunction properly or to be unnecessary for piping and support qualification.

Design Class 1 large and small bore piping isometrics are being reviewed toidentify snubbers located in close proximity to other rigid supports orancnors and to demonstrate compliance with piping and support allowablestresses. The criteria for the applicable proximity distance are described inparagraph B above and are identical to those used for the Unit 1 review.

Procedures

A review of all Design Class 1 large and small bore seismic analyses is .

being performed to identify all cases where snubbers are within thedefinition of close proximity described previously. The stress analysiscalculations which include these snubbers are being reanalyzed. assumingthe snubbers do not exist. If the displacement at any snubber locationis found to exceed 0.06 inch, the snubber would actuate and the previousanalysis is validated.

Where snubbers are found not to act (displacement equal to or less than0. 06 inch), the calculations are evaluated for stress and supportacceptance. Based on this review, compliance with piping and supportallowable stresses is demonstrated in one of the following ways:

o Demonstration that the snubber can be eliminated and maintainpiping and support qualification for all levels of earthquake

Demonstration that the snubber locks-up during one or more levelsof earthquake and is not required to maintain piping and supportqualification to the remaining earthquake levels

Where either of the above can not be demonstrated assuming a0. 06 inch snubber dead band, actual manufacturer test reportsdescribing the lost motion or dead band performancecharacteristics of the unique snubber are used to demonstrate

0014s/0022K

Results

qualification. The actual lost motion or dead band is compared tothe calculated motion and lock-up is either demonstrated or notrequired.

The review of proximate snubbers is currently in progress and will becompleted prior to fuel load. Based on the results of the review ofapproximately 80% of the pertinent piping isometrics 30 proximatesnubbers have been identified. Further reviews are heing performed tocompare calculated piping motion and snubber lost motion in order todetermine snubber operability.

D. THERtlAL GAP lhODELING (License Condition Item 4)

"PGandE shall identify all pipe supports for which thermal gaps have beenspecifically included in the piping thermal analyses. For these cases thelicensee shall develop a program for periodic inservice inspection to assurethat these thermal gaps are maintained throughout the operating. life of theplant. PGandE shall submit to the NRC Staff a report containing the gapmonitoring program."

All Design Class l. large and small bore piping analyses subjected totemperatures above 200 F, or attached to lines subjected to temperatures

~

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~

~ ~ ~above 200 F, were reviewed to identify where pipe/pipe support gaps weremodeled in the thermal analyses.

Thirteen calculations were identified with.30 support locations which had gapsmodeled in the analyses. All of these affected analyses will be revised, andqualification will be demonstrated for pipe stress, pipe supports, equipmentnozzle loads, and other analysis criteria prior to the first scheduledrefueling outage.

2.

All.large and small bore analyses of piping subjected to temperatures above2OO F, or attached to lines subjected to temperatures above 200 F, arebeing reviewed to identify all locations where pipe/pipe support gaps aremodeled in the thermal analyses. As with Unit 1, piping subjected to amaximum temperature of 2OU F or less is not included in the program sincegap repeatability at these temperatures is assured by the extremely smallexpansion which leads to consistent pipe behavior during thermal cycling.

Procedures and Criteria

The Unit 1 License Condition requires PGandE to perform periodicinservice inspections of all support gaps that were modeled in thethermal analyses to ensure their maintenance throughout the life,of the

0014s/0022K - 8-

plant. This may be undesireable due to ALARA concerns. Therefore,PGandE has established the criteria that all of the affected analyseswill be revised, and qualification will be demonstrated for pipe stress,pipe supports, equipment nozzle loads, and other analysis criteria.

Results

The review of all .large and small bore piping analyses affected by thisLicense Condition item has been completed. The results of this reviewindicate that there are no cases where pipe/pipe support gaps weremodeled in piping thermal analyses.

E. MOT PIPING WALKDOWN (License Condition Item 5)h

"PGandE shall provide to the NRC the procedures and schedules for the hotwalkdown of the main steam system piping. PGandE shall document the mainsteam hot walkdown results in a report to the NRC Staff."

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Walkdowns of the main steam piping as well as other piping in both the coldand hot condition to monitor thermal expansion were conducted by the Projectduring initial plant heatup and will continue during power ascension.Observed piping performance was shown to be within the Project design criteria.

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7As w>th Un> t 1, walkdowns of the main steam piping as well as other piping, inboth the cold and hot condition to monitor thermal expansion, were planned bythe Diablo Canyon Project during initial plant heatup and power ascension.The purpose of these programs is to further confirm that the piping andsupports are performing properly and generally as predicted. Any anomaliesare shown by supplementary analysis to be within the Project design criteria.

Procedures

Attachment 2 is Procedure P-36, "Walkdown of Piping During InitialMeatup," which describes walkdowns to be done for main steam piping, aswell as other piping during initial plant heatup. Attachment 3 isProcedure P-38, "Walkdown of Piping During Power Ascension," whichdescribes walkdowns to be done for main steam as well as other pipingduring power ascension.

7

These procedures have remained essentially the same as those used forUnit 1, with the exception of the addition of the requirement, whereappropriate, to measure and record the thermal plus seismic gap.

OU14s/0022K

Results

The activities governed by Procedure P-36 for walkdowns during initialplant heatup are currently in progress and are scheduled to be completedin November, 1984. Malkdown package documentation will be finalizedprior to fuel load and will be available in Project files.

F. PIPE SUPPORT DESIGN TOLERANCE CLARIFICATION (PSDTG)AND DIABLO PROBLEMS (DP) (License Condition Item 6)

"PUandE shall conduct a review of the "Pipe Support Design ToleranceClarification" program (PSDTG) and "Diablo Problem" system (DP) activities.The review shall include specific identification of the following:

( a) Support changes which deviated from the defined PSDTC program scope;

(b) Any significant deviations between as-built and designconfigurations stemming from the PSDTC or DP activities; and

(c) Any unresolved matters identified by the DP system.

The purpose of this review is to ensure that all design changes andmodifications have been resolved and documented in an appropriate manner.Upon completion, PGandE shall submit a report to the NRC Staff documenting theresults of this review."

Unit 1 Program

A program was established to demonstrate that the DP and PSDTG programs, andtheir impl'ementation,'id not detract from appropriate resolution anddocumentation of all design changes and modifications. The program consistedof two components; one addressed DPs and the other PSDTCs.

The DP review program reviewed all piping-related DPs issued since 1973 andfound 186 DPs related to piping which transmitted design-related information.Information transmitted by these DPs was found, with one exception, to beincorporated in the appropriate design documents and qualified by theassociated calculations. The one exception was satisfactorily resolved.

The PSDTG review program sampled changes authorized by the PSDTC program andfound them to be incorporated in the drawing and qualified by the associatedcalculations.

Unit 2 DP Review Pro ram

All Unit 2 piping-related DPs issued since the start of the ITP are beingreviewed to assure that, for those cases where the DP is found to containdesign information, the changes were properly documented in the plant designdocuments and calculations. The review covers DPs issued subsequent to August1982 since all safety-related piping and pipe supports have been reanalyzedafter that date, effectively superceding all prior piping-related DPs.

UU14s/0022K - 10-

Procedures

A program has been developed and is being implemented to assure that nosignificant deviations between as-built and design configurations orunresolved matters resulted from the DP system. The program requiresreview of all Unit 2 DPs issued since the start of the" ITP to identifythose which contain piping or pipe support-related information. The DPsidentified from this review are further reviewed to identify thoseconsidered to contain design-related information. Design-relatedinformation is defined as any information which allows, or could beconstrued to allow, construction to proceed with (1) work contrary toexisting design drawings and specifications, or (2) work not shown onexisting drawings or specifications. Those designs or installationsassociated with DPs found to contain design information are reviewed indetail to assure that the changes are properly documented in the plantdesign documents and calculations. These reviews are directed byprocedure and all findings are documented, including the details ofclosure of each DP considered to contain design information.

Results

The review of all Unit 2 DPs issued since August 1982 has been completedand the results indicate a total of 422 piping or pipe support-relatedDPs. The detailed review of these DPs is currently in progress and willbe complete prior to fuel load. To date, approximately 200 such DPs havebeen reviewed and none were found to contain design-related information.

Pi e Su ort Desi n Tolerance Clarification (PSDTC) Pro ram

No additional PSDTG review is considered necessary for Unit 2 for thefollowing reasons:

The PSDTC program was established to allow pipe support design changes to bemade by a qualified pipe support engineer located at the construction site,providing design criteria were not violated. The purpose of the program wasto provide expeditious resolutions of construction difficulties in theinstallation of large and small bore pipe supports in order to minimizeconstruction delays. The program allowed construction of such changes toproceed, at risk, based upon an engineering evaluation by an engineer at thejobsite. Although the details of the engineering evaluation were notdocumented, and calculations were not updated at that time, the judgment ofthe acceptability of the design change was approved in writing by the engineer.

The PSDTG program was considered to be an adequate program for controlling thework because of the comprehensive as-built program which documented andformally approved any modification to a pipe support. In all cases, anas-built was made for the pipe support following any construction workauthorized by a PSDTG. As the name implies, the as-built reflects thecondition of the pipe support as it was actually built, not necessarily asengineering originally designed it. This process assured that all relevantPSDTCs were incorporated in the as-built drawings and calculations.

0014s/0022K - ll-

( The process of as-built drawing preparation and verification, andreconciliation of the as-built drawing with the appropriate calculation, hasbeen rigorously controlled and includes many checks and reviews. Uponcompletion of construction of a support, an as-built is prepared by the pipingcontractor's engineering organization. This as-built, which includes changes

-allowed under the PSDTG program, is then provided to the piping contractor'squality control group. Yerification of correctness of the as-built isincluded as a part of- the final quality control acceptance and sign-off of thehanger installation. Following quality control acceptance< the hangerconstruction package is submitted to the piping contractor s quality assurancegroup for review and acceptance. Thus, the as-built is produced by a groupcompletely separate from the PSDTG group, and is done to completely separatequality control and quality assurance procedures.

The as-built hanger drawing is then forwarded from the piping contractor tothe Project construction organization, which for war ds it to Engineering forreconciliation with calculations and incorporation in the final plant designdrawing. The status of the support relative to this process, including allengineering review and drawing incorporation activities, is established andmonitored by a computer-based program developed specifically for pipesupports. Pipe support engineering personnel review each support as-built toverify and document compliance with design criteria. This review includescoordination with other piping disciplines such as stress analysis, whennecessary, as well as other engineering disciplines. The civil discipline isinvolved in these reviews to verify that structures or substructure designsare compatible with the loading caused by the pipe support.

The review completed by Unit 1 in response to this item of the LicenseCondition demonstrated the thoroughness and comprehensive nature of theas-built process. The procedures used on Unit 1 and Unit 2 are the same inthis regard. Therefore, there is a high confidence level that all changesauthorized by a PSDTC were incorporated in the support as-built drawing, whichsubsequently received final engineering review and acceptance.

Field Chan e Re uest Pro ram Description

The PSDTG program was discontinued for Unit 2 on June 8, 1984, and wassuperceded by a Field Change Request (FCR) procedure. The FCR procedureapplies to all field requested deviations from pipe support designs issued byEngineering where the proposed deviations are beyond approved installationtolerances. Construction initiates requests for such deviations on an FCRform and submits these requests to Engineering for review and approval. TheEngineering approval of the FCR includes justifications for acceptance anddocuments any required coordination which has occurred with other disciplinegroups to determine acceptance. Where a calculation is required to verify theadequacy of the proposed change, the calculation is completed in accordancewith Engineering Manual Procedure 3.3 prior to approval of the FCR. TheEngineering approval of an FCR will be indicated by the signature of theresponsible engineer, the group supervisor, and the Project Engineer.

001 4s/0022K - 12-

In the case of deviations proposed by Construction which do not alter thefunctional design characteristics of the pipe support, or which are minordesign drawing clarifications, General Construction Lead Discipline Engineerscan authorize in-process work to continue on an "at-risk" basis for up toseven days while Engineering approval of the FCR is being obtained. Theauthorization is provided in writing and is included in the pipe support workpackage before the work can proceed. This in-process change authority willexpire and work so authorized will cease if formal Engineering approval is notreceived within seven days.

For all pipe support modifications for Unit 2, the pipe support as-builtdrawings will continue to include any modifications authorized by a previousPSDTG or an FCR such that no deviations will exist between the as'-builtdrawing and any modifications authorized in the field. Final acceptance ofthe installed condition will continue to be the final Engineering review,checking, and approval of the as-built pipe support dr awing.

G. TECHNICAL TOPICS (License Condition Item 7)

"PGandE shall conduct a program to demonstrate that the following technicaltopics have been adequately addressed in the design of small and large borepiping supports:

(a) Inclusion of warping normal and shear stresses due to torsion in thoseopen sections where warping effects are significant.

(b) Resolution of differences between the AISG Code and Bechtel criteria withregard to allowable lengths of unbraced angle sections in bending.

(c) Consideration of lateral/torsional buckling under axial loading of anglemembers.

(d) Inclusion of axial and torsional loads due to load eccentricity whereappropriate.

(e) Correct calculation of pipe support fundamental frequency by Rayleigh'smethod.

(f) Consideration of flare bevel weld effective throat thickness as used onstructural steel tubing with an outside radius of less than 2T.

PQandE shall submit a report to the NRG staff documenting the results of theprogram."

Small bore piping was reviewed to address License Condition Item 7 as outlinedin License Condition Item l.

0014s/OU22K -13-

The large bore pipe support review was performed on a sample of 200 suppor tcalculations. All supports were considered qualified to the Project criteriawith one minor exception not related to the License Condition issues.

2. ~U "i 2 2

A discussion of the small bore program to address the issues of this License.Condition item is presented in paragraph A above.

All large bore, seismic Category I pipe supports are being reviewed for the"appropriate attributes of Item 7 of the License Condition.

Procedures

~ Attachment 1 is Instruction I-59; "Instruction for the Evaluation ofLicensing Condition No. 7 Concerns - Diablo Canyon Units 1 and 2," whichdescribes the procedures and criteria employed for this review.

As discussed in the Unit 1 response to this issue, in order to addressany future analysis performed on pipe supports, the design criteriacontained in M-9 for pipe supports were revised to require considerationof Item 7, parts (a), (c), ( d), and (e) of the License Condition. Part(b), concerning unbraced angles, will be used ~onl to qualify existingsteel members. A specific restriction will prohibit its use in thedesign of new supports.

Results

The review of large bore, seismic Category I pipe supports for theappropriate attributes of Item 7 of the License Condition is currently inprogress and will be completed prior to fuel load. The review is beingaccomplished as part of the final as-built acceptance process for alllarge bore pipe supports. To date, as-built reviews have been completedfor approximately 50'X of the large bore supports, many of which werecompleted prior to issuance of License Condition 2.C.(ll). The as-builtreview process, including License Condition Item 7 concerns, has beencompleted for approximately 25K of the large bore supports. The totalscope of this review involves approximately 3,500 large bore supports.

0014s/0022K