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| McGUIRE NUCLEAR STATION
REANALYSIS OF MATH MODELS:.
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FOR
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.
.
Sincerely,
kJ ~bE.
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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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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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| 2. Upset - Thermal Displacement--
N OBE (Displacement)_, } (Secondary Stresses) =g
'S
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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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