ML20154H012
| ML20154H012 | |
| Person / Time | |
|---|---|
| Site: | Farley  |
| Issue date: | 09/30/1998 |
| From: | BROOKHAVEN NATIONAL LABORATORY |
| To: | |
| Shared Package | |
| ML20154G968 | List: |
| References | |
| NUDOCS 9810140047 | |
| Download: ML20154H012 (6) | |
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SUBMirrAL-ONLY SCREENING REVIEW l
OF THE l
FARLEY NUCLEAR PLANT i
INDIVIDUAL PLANT EXAMINATION
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FOR j
EXTERNAL EVENTS i
(Seismic Portion) i i
l September 1997 i
L Brookhaven National Laboratory 9810140047 981001 PDR ADOCK 05000348 P
PDR opotuo047
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INTRODUCTION 1.1 Purpose in response to the NRC issued Supplement 4 to Generic Leuer (GL) 88-20, Individual Plam Examination of External Events (IPEEE) for Severe Accident Vulnerabilities - 10 CFR 50.54(f), the Southern Nuclear Operating Company (SNC) performed an IPEEE for the Farley Nuclear Plant (FNP), and submined the IPEEE results to NRC. Brookhaven National Laboratory (BNL), as rgW by NRC, has performed the subminal-only screening review to verify the technical adequacy of the_ seismic portion of SNC IPEEE subminal. His Subminal-only Screening Review presents the resuhs and conclusions of the BNL review and evaluation.
BNL's methodology utilized for the review followed the Fuidelines provided in the document titled Guidance for the Performance of Screening Reviews of Subminals in response to USNRC Generic Leuer 88-20, Supplement 4" (Draft. Oct. 24,1996).
1.2 Background
FNP is located in southeast Alabama on the west side of the Canahoochee River, about 16.5 miles east of Dothan, Alabama. De FNP units are essentially identical and share a common site.
Both units are a three-loop pressurized water reactor (PWR) manufactured by Westinghouse, with an electric j
output of 861 MWe. Unit I began commercial power operation in December 1977, and Unit 2 began operation in July 1981.
4 De safe shutdown earthquake (SSE) for the site is 0.lg. and the plant is binned in the reduced-scope category, i
1.3 Licensee's IPEEE Process and Licensee's Insights
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De FNP reduced-scope seismic margin assessment (SMA) was performed using the EPRI SMA methodology i.
as part of a combined IPEEE and USI A-46 Program. Since FNP is categorized as a reduced-scope plant, l
the SSE ground response spectra with a PGA of 0.lg were used as the IPEEE RLE. For the component screening and eva:uation, the Seismic Qualifration Utility Group (SQUG) Generic Implementation Procedure j
(GIP) was used for both units. For items not covered by the SQUG GIP, the guidances from EPRI NP-6041 j
were used.
1 De site is located wnhin an area that has infrequent seismic activity. De evaluations of potennal soh Ere and relay chauer are not required for the plant. However, a USI A 46 relay evaluation was performed for Unit 1, and the results are included in a separate report already submined to the NRC in May 1995. After walkdowns, a total of 498 equipment / components for Unit I and 389 for Unit 2 were selected in the SSEL.
As a result of screening, a total of 117 outliers were identifad, and listed in the submittal together with the reasons for retention in such as an anchorage problem.
In accordance with the SMA methodology, preferred and ahernate success paths were selected for each unit.
Both success paths assume loss of offsite power (LOOP) and a small LOCA, and are identical in equipment I
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configurmion. De only difference is that the preferred path is for the A-train RHR system, and the alternate path utilizes the B-train.
j The IPEEE analysis concluded that installed equipment is generally rugged and well anchored. A limited i
number of anchorage and irneraction concerns were idemified with regard to the evaluation criteria. However,
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k was concluded that none of these concerns were determined to impair component operability, and all are scheduled for resolution.
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REVIEW FINDINGS i
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2.1 IPEEE Format and Methodology Documentation j
De subminal was orgamzed in a format consistem with the guidelines of NUREG-1407, and the methodology
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used in the seismic analysis was described in sufficiem detail. All major IPEEE related issues and certain generic issues were addressed. Therefore, h was concluded that the IPEEE format and methodology j.
documentation a'e adequate.
l 2.2 Scismic Review Team (SRT) Selection De seismic review team (SRT) enmia*A of personnel from th : Southern Nuclear Operating Company (SNC),
i who were the subcontrr: tor for the IPEEE seismic analysis, a ad personnel from the FNP, who were familiar l
with the system and operation procedures. Detailed desciiptior;, on the team members' background are 2
provided in the submitt:J, and it is concluded that the SRT sekstion meets the NUREG-1407 objectives.
2.3 Seismic Input
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Since FNP is categoris.ed as a reduced-scope plant, the SSE ground spectra with a PGA of 0.lg was used as 4
the IPEEE review levol earthquake (RLE). When IRS were required, a factor of 1.5 was applied to the SSE
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spectra to represent the building IRS for components located less than 40 ft above grade with a natural 1
frequency above 8 'h. New IRS were developed for other components with a lower natural frequency. It i
is concluded that the methodology meets the guidelines of NUREG-1407.
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2A Success Path Selection and Safe Shutdown Equipment List (SSEL)
In accordance with the EPRI SMA methodology, a primary and an ahernate success path were selected for cach unit. Success path logic diagrams (SPLDs) for both the primary and alternate paths are provided in the submittal (Figures 3-16 and 3-17, respectively). Both the success paths assume loss of offsite power and a j
small LOCA. They are idernical in equipment configuration, but are independent of each other with the i
exception of the comrol rod drive (CRD) system. A detailed description of the functions of all the systems l
along the paths, as well as the SSEL are provided in the subminal. It is concluded that the selection of the success path is consistent with the guidelines of NUREG-1407.
De success paths contain.w J.y cooling via steam generators using auxiliary feedwater, RCS makeup by chargirig pumps, and long term cooling by the residual heat removal (RHR) system or by recirculation from j
the contammem sump. For a measure of diversity, feed and bleed cooling is also evaluated as a backup to the secondary cooling, with charging pumps and PORVs operating to renme the decay heat.
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Even though the two paths use the same systems, there is sufficiem diversity because both a small LOCA and a 1.OOP are consklered in both paths, and feed and bleed cooling is considered as an alternative to the steam generator cooling.
2.5 Plant Walkdown Approach
'!he seismic capacity walkdown for SSEL components was performed according to the requiremems of the EPRI SMA methodology and the SQUG GIP. A sheet was added to the GIF forms to address the relay walkdown, which is required for A 46, and seismic imeraction for flooding. Evaluation of components was
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performed on 1) adequacy of anchor bolts and weld anchorage 2) quick conservative calculation of seismic capacity based on weight, natural frequency, and anchorage strength 3) seismic spatial interaction. A total of 498 componems for Unit I and 389 components for Unit 2 were evaluated during the walkdown. The results of the walkdown were summarized on the screening verification data sheets (SVDS). A total of 117 outliers were identified and listed in the submittal (Appendix 3H). The procedure used in walkdowns to address the
' IPEEE/A-46 requirements appears adequate.
2.6 Structural Analysis and HCLPF Calculation Ahhough reduced scope plants are not required to perform a HCLPF calculation, a rather detailed evaluation of the seismic capacity of structures and components was conducted and described in the submittal. Most of the components were evaluated based on the SSE GRS per table 4-3 of the SQUG GIP New SSI analyses were conducted for the DG and SW intake structures, which are supported on cast in-place caissons.
2.7 Soil Evaluation New scil evaluation analyses were not performed in the IPEEE study because soil failure analyses are not required for reduced-scope plants.
2.8 Relay Chatter Evaluation Because FNP is categorized as a reduced-scope IPEEE plant, an evaluation of relay chatter is not required by 4
NUREG-1407. However, an USI A-46 relay evaluation was performed per the SQUG GIP for FNP Unit 1, and the results are included in a separate report, which was submined to the NRC in May 1995. Although not required, an evaluation of relay chatter is being performed for Unit 2 as a prudent measure.
2.9 Containment Performance
'!he earlier FNP IPE study concluded that the plant is not vulnerable to early containment failure. Based on this finding, only comainmem isolation failure was addressed as part of the IPEEE seismic analysis. A set of screening criteria were used to evaluate containment penetrati<ms larger than 2 inches in diameter. 'Ibe subminal concluded that all containment isolation valves included on the SSEL were demonstrated to possess
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a seismic capacity of at least 0.lg PGA. It is concluded that the conuinment performance evaluation i
procedure is consistent with the guidelines of NUREG-1407.
2.10 Nonseismic Failures and Human Actions
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Nonseismic failures and human actions were not di==ad as a separate subject in the subminal. However, equipment which requires operator actions was included in the seismic evaluation. No credit was given for recovery of offsite power loss.
2.11 Seismic Induced Mres/ Moods As part of the seismic capacity walkdown, all potential internal flooding sources, mainly piping and tanks, were evaloated by the SRT in areas con'aining SSEL equipment. De subminal concluded that no flooding concerns were identified because piping has a high seismic capacity, and all tanks were well anchored.
The seismic-fire interaction evaluation addressed the interaction concerns: 1) seismically induced fires,2) seismic actuation of fire suppression systems,3) seismic degradation of fire suppression systems. Based on walkdown findings and evaluations, the submittal concluded that no seismic-fire interaction issues exist at a seismic capacity of at least 0.lg PGA. It is concluded the above evaluation procedures are consistent with the guidel,ines of NUREG-1407.
2.12 Unresolved Safety Issues (USIs) and Generic Issues (GIs)
Information in the submittal regarding pertinent USIs and GIs is as follows:
l USl A-45 DHR capability was specifically addressed in Section 3.2.1 of the submittal.
1 USI A 46 Issues were addressed in Sections 3.1.1.4.1 and 3.1.1.5.12 of the subminal.
The complete evaluation for USI A-46 was included in a separate repon.
GI 131 This was addressed in Section 3.2.2 of the subminal. De flux mapping I
system (FMP) cart hold-down bolts were replaced to comply with the I
Westinghouse recommendation.
USI A 17 De seismic interaction was addressed in the IPEEE seismic analysis.
G1156 Seulement of foundations and buried equipment are not concerns for FNP, but detailed valuations of buried structures, piping and ducts were l
performed. (Section 3.1.4.3 of submittal). Seismic design of structures, systems, and components was addressed in the subminal by performing the SMA.
GI 172 Most related issues are addressed in the subminal as follows:
1) common cause failures related to human action were not specifically addressed in the subminal.
2) seismic induced spatial interactions are addressed as part of the walkdown l
in Section 3.1.1.4.
3) seismic induced fires as well as fire suppression system actuation are addressed in Section 3.1.4.7.
4) seismic induced flooding was not specifically addressed, but praa' int failures of dams and dikes are addressed in Section 3.1.1.5.6.
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Section 3.1.4.5 states that an A-46 relay evaluation was performed al the i
results are included in a separate report.
2.13 Vulnerabilities / Plant Improvements L
No dermition of seismic vulnerability was provided in the submittal, however, a total of 117 outliers were identified and listed, it is stated that many of them have been resolved either through the implementation of l
design changes or the plant maintenance process. SNC planned to resolve outliers identified in the subminal by December 31,1995. It is also stated that relays that did not satisfy the SQUG GIP criteria would be resolved. De list of the outliers is attached to this report as Appendix A. Most of the proposed resolutions involve the following types of actions:
1) installing restraining wires for overhead lights, 2) replacing anchor bolts, 3) bolting panels to walls or bolting cabinets together, l
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installing missing screws, and l
5) performing additional detailed analysis.
l 3.0 OVERALL EVALUATION AND CONCLUSIONS De submittal appears to be consistent with the guidelines of NUREG-1407. He IPEEE seismic evaluation was performed as an extension of the USI A-46 program. The screening review has identified no significant technical drawbacks and the licensee's IPEEE process appears to have met the objectives outlined in Generic Letter 88-20.
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FARLEY NUCLEAR PLANT INDIVIDUAL PLANT EXAMINATION OF EXTERNAL EVENTS (IPEEE)
TECHNICAL EVALUATION REPORT FIRES l
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