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| McGUIRE NUCLEAR STATION

REANALYSIS OF MATH MODELS:.

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ENVELOPE SPECTRA

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AUGUST 14, 1981

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i 8108310358 810824'PDR ADOCK 05000369

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1.0 INTRODUCTION

This report summarizes the results of the reanalysis of 22 pipingmath models for McGuire Nuclear Station, Unit 1, which was requiredby the Nuclear Regulatory Commission in its letter of April 8,

1981 ( AttachTent 1). These math models were identified in DukePower's report, " Review of Piping Seismic Analysis Methods" ofMarch 2,1981, as using spectra analysis methods different fromthe envelope of all spectra as specified in the Standard ReviedPlan 3.7.3. The NRC letter requested these math models to bereanalyzed to include the envelope spectra method. Table 1 is alisting of the 22 math models which fall in the scope of thisreanalysis .

The topics addressed in this summary report are listed in Part 2of Attachment 1. The following sections and tables summarize

the analysis results of each math model and present the acceptancecriteria for each topic.

2.0 ANALYSIS RESULTS

2.1 Loading Conditions

The piping in all the reanalyzed math models is ASME Class 2 or 3or non-ASME (Duke Classes B, C or F). Table 3.9.2-1 of the McGuireFSAR (Attachment 2) lists the loading conditions for these particularclasses of pipe. The loading conditions reanalyzed for these mathmodels were the Operating Basis Earthquake (0BE) and the Safe Shutdown

Earthquake (SSE). The results of the other loading conditionswere obtained from existing analysis and combined with the OBEand SSE loads for evaluating code combined stresses, support /

restraint design and nozzle loads on equipment, as appropriate,

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2.2 Code Computed Stresses

The McGuire Nuclear Station, Unit 1 piping analysis was performedusing the load and stress criteria listed in Attachment 2 and thecorrespcoding code equations in paragraph NC-3652 of the 1971 ASMESection III Code, Winter 1972 Addenda, the Code of Record for

McGuire piping analysis. Since the reanalysis of the 22 math modelsinvolved only the OBE and SSE loads, only the Upset (ASME Equation 9)

and Faulted Conditions were evaluated. All other design conditionswere met by the previous analysis. The Dynamic Internal FluidLoads (DSL) noted on Attachment 2 were actually combined with the

Upset loads, as required by Equation 9, as well as the Faulted loads.

The largest Upset (Equation 9) stress is tabulated in Tables 2 and3 for each math model along with the corresponding allowable stress

(1.2 S ). The sixteen (16) math models in Table 2 were reanalyzedhto include the appropriate Reactor Building spectra because these -math models attached to this structure at a containment penetration.As seen from Table 2, no math model had an Equation 9 stress toexceed its allowable value.

Table 3 lists the six (6) math models which were previously identifiedas using multiple spectra methods for seismic analysis. The mathmodels were reanalyzed with their appropriate boundaries to includethe envelope spectra for each. Again, no math model had Equation 9stresses to exceed its allowable value.

Safe Shutdown Earthquake stresses were not directly evaluated forMcGuire Nuclear Station, Unit 1. It can be seen from Attachment 2that stresses combined for the Faulted Condition are identical tothe Upset plus DLS when the SSE stresses are substituted for theOBE stresses. Since SSE stresses are 15/8 OBE and the allowablestress for the Faulted Condition is two times that for the Upset

Condition, it can be seen that if the Upset stresses are less thanthe Upset allowable stresses, the Faulted stresses will be lessthan the Faulted allowable stresses.

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2.3 ASME Service Level Allowables

The allowable stresses listed in Attachment 2 were used for eachdesign condition rather than the ASME Service Level allowables.The service level allowables were introduced in a version of thecode later than the Code of Record for McGuire Nuclear Station.

| 2.4 Support / Restraint Loads

New SSE loads were generated for all support / restraints (S/R)

in each reanalyzed math model. For this reanalysis, SSE response

spectra were used with the allowed SSE damping values listed inRegulatory Guide 1.61. The previous analysis of these math models

used OBE spectra and OBE damping values with the results beingratioed by 15/8 to obtain SSE results. The conservatism of thisratio method in obtaining S/R loads was substantiated from thereanalysis. Even though higher floor spectra were used in theenvelope reanalysis, only a small percentage of the total numberof 5/R's actually had SSE load increases over the previous analysisand, furthermore, no additional S/R's were required.

Table 2 summarizes the S/R results of the envelope spectra reanalysis

of the 16 containment penetration math models. Seven of these 16math models had no SSE load increases. This was mainly due tothe conservatism of the previously discussed method for obtaining

SSE loads.

Table 3 presents a summary of the S/R results for the six math modelspreviously analyzed using multiple spectra methods. These mathmodels were analyzed with their appropriate overlap boundaries

and using the envelope spectra methods. Since the steam generator

spectra was included in the envelope for these math models, ahigher percentage of S/R had SSE load increases.

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2.5 Support / Restraint Acceptance Criteria

The S/R loads generated by the envelope spectra analysis were compared

to the allowable loads in each S/R design calculation. All existingS/R designs for the math models listed in Table 2 were acceptablefor the new loads except for one S/R in Math Model FWA. This S/R

required field modification under the station modification program.

All but seven (7) S/R's for the math models listed in Table 3were likewise acceptable. These seven S/R's are in math models

which attach to the Steam Generator at a single nozzle whichtheoretically required its spectra to be included in the envelope.However, due to the large size of the math models, an analysiswas performed to determine the portions of the piping systemsactually influenced by this spectra. This analysis determinedthat the seven S/R's are not on a portion of the pipe which isexcited by the Steam Generator. Des.igns for these S/R's arequalified for the envelope spectra applicable to that portion of

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the piping system by which they are excited. As such, designsfor these S/R's are adequate without modification.

2.6 Equipnent Nozzle Loads and Acceptance Criteria

The equipment nozzle loads generated by the envelope spectra analysis

|were reviewed against the allowable loads. All equipment had allowable

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nozzle loads higher than the new loads.

2.7 I.E. Bulletin 79-02

The reports which were previously submitted by Duke Power Company

stating its compliance with IE Bulletin 79-02 are still valid for

S/R's in the math models which were reanalyzed for envelope spectra.Therefore, no new data concerning this Bulletin is required.

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3.0 McGUIRE NUCLEAR STATION, UNIT 2

The procedures for piping analysis for McGuire Unit 2 requirethe use of envelope spectra. Hence, no further information is

required to show compliance with Attachment 1 for this unit.

4.0 CONCLUS SN

The reanalysis of the twenty-two (22) McGuire Nuclear Station,Unit 1 piping math models for envelope spectra provided evidenceof the conservatisms in the existing design of piping and support /restraint components as well as in analysis methods. The allowablestress was not exceeded for any piping component in any of thesemath models.

Evidence of additional conservatisms comes from the review of thesupport / restraint designs. Only one S/R required hardware changesfor the envelope spectra loads. The majority of the support /restraints (83%) had no load increases from the previous analysis,mainly due to the use of OBE damping values in calculating SSEloads instead of the higher SSE damping values allowed in RegulatoryGuide 1.61.

The reanalysis of 22 piping math models described in this reportdemonstrated adequate safety nargins in piping stress levels andpipe support loads.

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,y y" p, f(k[.N NifCLIlh'R RhGd TOdY COMMISSION,,f- /.E n ASHINGTord. D. C. 20555

ATTACHMENT 1; ..

/{Shd[j8 APR LO Page 1 of 3#

{***** EO-

,. . fi ., . h Nlb'Dcciet Nos. : -50'-369

and 50-370.

Duke Powei CompanyATTil: Mr. William O. Parker, Jr.

Vice President - Steam ProductionP. O. Box 33189422 South Church StreetCharlotte, North Carolina 28242

Dear Mr. Parker:.

Subject: Piping Seismic Analysis Methods (McGuire Nuclear Station, Units 1 & 2).

Your report, " Review of Piping Seismic Analysis Methods" of March 2,1981indicates that in 22 out of 355 piping math models, the seismic analysisportion of the design used reponse spectra other than the envelope spectraas required by Standard Review Plan 3.7.3. We find that the informationsubmitted is not acceptable to justify this deviation from the SRP.. We will,therefore, require that the safety margin of these piping math c.edels becetermined by reanalyzing and including the envelope of the spectra in theseismic portion of the analysis.

Specifically, we request that you provide the following information:

1. A list of all reanalyzed problems.

2. For each piping problem:a. Prescribed loading conditions.

vb. / The largest code computed stresses for the combined loadingconditions and its locat' ion.

v c. Corresponding ASME Service Level allowable.d. Internal loads on all supports, and at equipment nozzles.e. Corresponding allowable loads and the basis for their

acceptability.f. t Confirmation of Base ' plate bolt ' factors of' safety pertIE

rBulletin 79-02. *|

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APR 8 1981* 2-- ,

We consider that submittal of the requested infonnation will meet our 90day reanalysis requirement described in Section 3.7.2 of Supplement No. 5to the Safety Evaluation Report.

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Sincerely,

kJ ~bE.

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- Oj fir. William 0. Parker, Jr. Page 3 of 3 ]i- ' lice President, Steam Production

Duke Power Company* -P. O. Box 2178 .422 South Church StreetCharlotte, North Carolina 28242

cc: Mr. W. L. Porter Mr. Tom DonatDuke Power Company Resident Inspector McGuire NPSP. O. Box 2178 c/o U.S. Nuclear Regulatory Commission422 South Church Street . Post Office Box 216Charlotte, North Carolina 28242 Cornelius, North Carolina 28031

Mr. R. S. Howard Shelley Blum, EsquirePower Systems Division 1402 Vickers Avenue'-Westinghouse Electric Corporation Durham, North Carolina 27707P. O. Box 355 !Pittsburgh, Pennsylvania 15230 Dr. Richard F. Cole

Administrative JudgeMr. E. J. Keith U. S. Nuclear Regulatory CommissionEDS Nuclear Incorporated Washington, D. C. 20555

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220 Montgomery StreetSan Francisco, California 94104 .

Mr. J. E. Houghtaling -NUS Corporation .2536 Countryside BoulevardClearwater, Florida 33515 .

Mr. Jesse L. Riley, President.

The Carolina Environmental Study Group854 Henley Place .Charlotte, North Carolina 28207 .

J. Michael McGarry, III, Esq..

Debevoise & Liberman1200 Seventeenth Street, N. W. .Washington, D. C. 20036

/Robert M. Lazo, Esq., ChairmanAtomic Safety and Licensing BoardU. S. Nuclear Regulatory CommissionWashington, D. C. 20555.

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Dr. Emmeth A. LuebkeAtomic ifety and Licensing Board.U. S. Nuclear Regulatory Commission -

Washington, D. C. 20555 .

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;ATTACitMENT 2

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Table 3 9.2-1 .l''%

Stress Criteria for Piping

Duke Classes 8. C and F

C0tJD I T 10fl LOADS CRITERIA

1. Normal ThermalDisplacemenh ASME lil, Class 2- .Pressure -Weight

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N OBE (Displacement)_, } (Secondary Stresses) =g

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PressureWeight - )(PrimaryStresses) = 1.2 S

hOBE (inertia) .._

| 3 Faulted PressureWeight - ] (Primary Stresses) = 2.4 S

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SSE (inertia) h q51 DSL*1

4. Faulted Pressure * 110*6

)'._ (Primary Stresses) = 2.4 S

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TABLE 1

MATH MODELS REANALYZED FOR ENVELOPE SPECTRA

SYSTEM MATH MODELS

1. . Steam Generator Blowdown Recycle - BB 1. BBW, BBX, BBY, BBZ

2. Auxiliary Feedwater - CA 2. CAM, CAN, CAO, CAP

73. Feedwater - CF 3. CFC

4. Refueling Water - FW 4. FWA;

5. Residual Heat Removal - ND 5. NDA_

6. Safety Injection - NI 6. NIB, NID, NIE, NIK, NIU

7. Chemical and Volume Control - NV 7. NVA, NVS, NVU

8. Containment Ventilation Cooling~

8. RVAWater - RV

9. Main Steam - SM 9. SMA

: 10. Containment Air - VX 10. VXA! ii |

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TABLE 2 |

, CONTAINMENT PENETRATION MATH MODELS r| STRESS AND SUPPORT / RESTRAINT REANALYSIS SUMMARY

Stress Summary Support / Restraint Suninary

i Largest ASME No. of S/R No. of S/R With Basis| Eq. 9 Eq. 9 Stress per SSE Load for

Math Model Stress Allowables Ratio M.M. Increases Acceptance [BBW 16111 19080 .844 54 3 S/R Design ReviewBBX 16566 19080 .868 57 None --BBY 15502 19080 .812 53 6 S/R Design ReviewBBZ 18278 19080 .958 56 None --,

| FWA 17928 19680 .911 149 16 Note 1NDA 20012 21492 .931 117 9 S/R Design Review.NIB 12205 21492 .568 25 8 S/R Design Oeview-

1 NID 19074 21360 .893 _17 None --NIE 12794 20635 .620 9 2 S/R Design ReviewNIK 14904 21492 .693 45 None --NIU 18132 22320 .812 23 9 S/R Design ReviewNVA 18088 20640 .876 Note 2~-- --NVS 15724 19522 .805 -35 10 S/R Design ReviewNVU 11208 21000 .534 30 None -- 'RVA 14284 18000 .794 22 None --VXA 3708 18000 .206 6 None --

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Notes:,

1. One support / restraint was identified as not being acceptable for the new loads. A stationmodification project was initiated to update the support / restraint to handle the envelopespectra loads.

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2. The piping in this math model was rerouted for a station mr.dification. Envelope spectra >was used and support / restraints. were redesigned for new locations and loads.

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PREVIOUSLY MULTIPLE SPECTRA MATH MODELSSTRESS AND SUPP0P.T/ RESTRAINT REANALYSIS SUMMARY ;4

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Stress Sumary Support / Restraint Sumary'

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| Largest ASME No. of 5/R No. of S/R With BasisEq. 9 Eq. 9 Stress per TSE Load fori

Math Model Stress Allowables Ratio M.M. ...c reased Acceptance<4 ICAM 17110 18000 .951 93 21 S/R 1.esign Review

| CAN 19933 21000 .949 77 7 S/R Cisign Review

CAO 20378 21000 .971 97 35 S/R Design Review

.CAP 20384 21000 .971 92 13 S/R Design Review

CFC 17164 18000 .954 148 26 Note 1

M SMA 12639 21000 .602 - 94 60 Note 1'

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1. All supports / restraints were approved by the S/R Design Group and approved Tcr t.he envelopeof all spectra except for 4 in Math Mooel CFC and 3 in Math Model SMA for all spectra.Acceptance of these seven S/R's is discussed in Section 2.5 of this report.

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