ML19209B541
| ML19209B541 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 06/19/1979 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML18136A035 | List: |
| References | |
| NUDOCS 7910100083 | |
| Download: ML19209B541 (3) | |
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s NINE MILE POINT UNIT 1 NUCLEAR POWER PLANT REVIEW OF PIPING REANALYSIS PER I&E BULLETIN 79-07 SAFETY EVALUATICN REPORT INTRODUCTI0r By letters dated April 25, 1979 and June 12, 1979 the licensee (Niagara Mohawk Power Corporation) responded to Inspection and Enforcement (I&E)Bulletin 79-07 (dated April 14,1979) for Nine Mile Point Unit 1 Nuclear Power Plant.
Seven systems located inside r.ontainment were identified as.aving been designed using an incorrect piping comp' uter code. Thesa systems have been reanalyzed with a code which uses acceptable seismic response combination techniques and the new results showed that piping stresses remained within code allewable (ASA S31.1, 1955) and that piping support., penetrations, nozzles and ecuipcent loadings remained within original design conditions.
DISCUSSION The affected systems identified by the licensee are:
A.
Reactor Recirculation B.
Emergency Condenser Returns D.
Reactor Cleanup E.
Reactor Drain F.
Reactor Feedwater G~.
Control Rod. Drive NMPC has stated that the method of algebraic (considering signs) summation of the codirectional spatial components was used for the original analysie of safety related piping systems as identified above at Nine Mile Point Unit 1 during 1972.
The computer code used was the 1972 Version of ADLPIPE Code.
The licensee has indicated that the follwing computer codes were used in the reanalysis of these systems.
ADLPIPE - Teledyne Engineering Services (TES)
TMRSAP - Teledyne Engineering Services (TES)
TES has state.d that it used a version of ADLPIPE, dated 1975, thru the CDC Cybernet system.
is c de was used to generate responses :o the incivicual seisr.ic excitation n:or:0nents. The modal res:onse due to each excitation sere cr:ine: (internally)
Se 50,55 me:hce; these res:enses were then ccm:inec exte-ai'j ( anually)
- 50 by :ne SP.SS method.
Since the coe. iqation of the es: rses to :ne earth-
- 27.e co.;0nents is
- erf 0med externally, TES has nct bee re:;sste to submit
- e Or ran listing of this version of ACLP:FE; -hey ha<e, 90,e.er, descriced
- ei-etn:c Of 00m iqation arc have corm;;ec ; sc' ve a Ie c# NO. - ger. era ec r e :-~i#r Or ler! as a r*.
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791050 P00RORGN4,
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= TES has also state'! that it used the code TMRSAP. Thi.s is a prcprietary version of the code SA? IV which uses absolute summation for the intra odal co enents and SRSS for the intemodal cmponents.
No modifications were made to the dynamic response portion of the code.
In addition, a set of NRC benchmark preslems are presently being solved by fES as part of the code verification effort.
hMPC has indicated that the company, in conjunction with an Inspection and Enforce-ment inspector, verified that the drawings accurately depicted the as-built condition of the plant.
The licensee has stated that with the exception of the cleanuo system discharge, all of the piping sys.tems identified above were reanalyzed in April 1979 using the updated ADLPIPE cmputer code.
The results of these reanalyses show that stresses of all piping remain within code allowable ranges and the strength of structural attachments is within the design conditions.
The licensee has also stated that in late 1978 through early 1979, seismic analysis was perfomed for the re-route of the Cleanup System discharge to the-Feedwater System by Teledyne Engineering Services using the TMRSAP Code.
The TMRSAP Code calculated the earthquake component effects simultaneously.
For each mode codirectional components were added absolutely after which modal values were combined by the Square Root of the Sum of Squares method. This coce will be verified as part of the NRC Code verification effort.
The licensee has indicated that the relatively minor increased stress levels at certain points in the reanalyzed piping lines has no effect on their pipe break analysis.
The NMPC's response to I&E Bulletin 79-02 states that the reanalysis has resulted in. stress increases at ten restraints. These restraints have been reanalyzed pnd found acceptable to support the increased loads. Since the restraints where loads have increased are not supported by concrete anchor bolts, the reanalysis has no effect on the testing and inspection perfomed under I&E Bulletin 79-02.
In response to I&E Bulletin 79-04 the licensee has indicated that no VELAN swing check valves are installed in Seismic Category I piping systems at Nine Mile Point Unit 1.
EV'LUATION
'he reanalysis method used was a lumped mass response spectra modal ar.alysis.
The af erity cf piping systems reanlay ed used Regulatory Guide 1.92 for the crbin-a-':.s of cdal responses and spatial cor.ponents.
This cyr.ar'c analysis procedure
's acce:O:le.
The procedure used for the clean-up system cischarge to the eec-a er Sys e-- is also acceptable.
3-For the seven systems of concern the licensee utilized the compu er codes as is, discussed above.
In addition to satisfying the code verification recuirements, the licensee has also agreed to provide the NRC two problems for confirmatcry analyris Th'ese confirmatory problems will be solved independently by censultants to the NRC at Brockhaven National Laboratory.
The models submitted for these piping problems will be confirmed by the licensee as correspencing to the "as-built" condition. We find these ccmmitments acceptable.
We find the licensee's responses concerning I&E Bulle.in 79-02 and 79-04 accept-able for the piping systems reanalyzed.
The reanalys:s has no ef ~ect on Nine Mile Point Unit I pipe break criteria for the piping systems int aved.
CONCLUSION Based on the discussion and evaluation presented above, we conclude'that the requirements set forth in I&E Bulleti-79-07 are adequa ely satisfied to allow resum: tion of power operation. provide that the informa-ion necessary for code verification be provided within 30 days of unit startup.
P00R ORGINA 1131 354 e
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