ML20148H513
| ML20148H513 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 06/05/1997 |
| From: | James Shea NRC (Affiliation Not Assigned) |
| To: | Hunger G PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| References | |
| REF-GTECI-A-46, REF-GTECI-SC, TASK-A-46, TASK-OR GL-87-02, GL-87-2, TAC-M69469, TAC-M69470, NUDOCS 9706100306 | |
| Download: ML20148H513 (8) | |
Text
June 5, 1997 o
i Mr. George A. Hunger, Jr.
Director-Licensing, MC 62A-1 PECO Energy Company Nuclear Group Headquarters Correspondence Control Desk P.O. Box No. 195 i
Wayne, PA 19087-0195
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION (RAI) ON THE RESOLUTION OF UNRESOLVED SAFETY ISSUE (USI) A-46, PEACH BOTTOM ATOMIC POWER STATION, UNITS 2 AND 3 (TAC N05. M69469 AND M69470)
Dear Mr. Hunger:
In its letter of May 7, 1996, PECO Energy Company (PECO) provided the plant-specific summary report in accordance with its commitment relating to Generic Letter 87-02 on the resolution of USI A-46 at the Peach Bottom Atomic Power Station, Units 2 and 3.
The NRC staff has reviewed tce summary report and determined that additional information is necessary in order to complete the review of the licensee's A-46 response. The staff's RAI is included as an enclosure.
PECO is requested to respond to this RAI within 90 days from the date of this letter.
If you have any questions, please do not hesitate to call me at (301) 415-1428.
Sincerely, (Original signed by)
Joseph W. Shea, Project Manager Project Directorate I-2 Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation Docket Nos. 50-277/278 gg g{ @[hh h
Enclosure:
RAI cc w/ enc 1: See next page I
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June 5, 1997 l
Mr. George A. Hunger, Jr.
Director-Licensing, MC 62A-1 PECO Energy Company Nuclear Group Headquarters Correspondence Control Desk P.O. Box No. 195 Wayne, PA 19087-0195 1
i
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION (RAI) ON THE RESOLUTION OF UNRESOLVED SAFETY ISSUE (USI) A-46, PEACH BOTTOM ATOMIC POWER STATION, UNITS 2 AND 3 (TAC N0S, M69469 AND M69470) l
Dear Mr. Hunger:
In its letter of May 7, 1996, PECO Energy Company (PECO) provided the l
plant-specific summary report in accordance with its commitment relating to Generic Letter 87-02 on the resolution of USI A-46 at the Peach Bottom Atomic l
Power Station, Units 2 and 3.
The NRC staff has reviewed the summary report l
and determined that additional information is necessary in order to complete l
the review of the licensee *s A-46 response.
The staff's RAI is included as an enclosure.
i PECO is requested to respond to this RAI within 90 days from the date of this letter.
If you have any questions, please do not hesitate to call me at (301) 415-1428.
l l
Sinc 1
l r
o Jose b.
hea, Pro ect Manager l
Proj ct Directorate I-2 i
Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation Docket Nos. 50-277/278 l
Enclosure:
RAI cc w/ encl:
See next page l
1
?
1 l;
Mr. George A. Hunger, Jr.
Peach Bottom Atomic Power Station, l
PECO Energy Company Units 2 and 3 i
cc:
l 1
l J. W. Durham, Sr., Esquire Chief-Division of Nuclear Safety Sr. V.P. & General Counsel PA Dept. of PECO Energy Company Environmental Resources 2301 Market Street, S26-1 P.O. Box 8469 Philadelphia, PA 19101 Harrisburg, PA 17105-8469 l
PECO Energy Company ATTN: Mr. T. N. Mitchell, Vice President Board of Supervisors Peach Bottom Atomic Power Station Peach Bottom Township 1848 Lay Road R. D. #1 3
Delta, PA 17314 Delta, PA 17314 l
PECO Energy Company Public Service Commission of Maryland ATTN: Regulatory Engineer, A4-5S Engineering Division i
Peach Bottom Atomic Power Station Chief Engineer 1848 Lay Road 6 St. Paul Centre i
Delta, PA 17314 Baltimore, MD 21202-6806 Resident Inspector Mr. Richard McLean U.S. Nuclear Regulatory Commission Power Plant and Environmental Peach Bottom Atomic Power Station Review Division P.O. Box 399 Department of Natural Resources Delta, PA 17314 B-3, Tawes State Office Building Regional Administrator, Region I U.S. Nuclear Regulatory Commission Dr. Judith Johnsrud 475 Allendale Road National Energy Committee King of Prussia, PA 19406 Sierra Club l
433 Orlando Avenue l
Mr. Roland Fletcher State College, PA 16803 Department of Environment 201 West Preston Street Manager-Business & Co-owner Affairs Baltimore, MD 21201 Public Service Electric and Gas l
Company A. F. Kirby, III P.O. Box 236 External Operations - Nuclear Hancocks Bridge, NJ 08038-0236 Delmarva Power & Light Company P.O. Box 231 l
Wilmington, DE 19899 Manager-Peach Bottom Licensing i
PECO Energy Company i
PECO Energy Company Nuclear Group Headquarters i
l Plant Manager Correspondence Control' Desk l
Peach Bottom Atomic Power Station P.O. Box No. 15:
1848 Lay Road Wayne, PA 19087-0195 Delta, PA 17314 1
REOUEST FOR ADDITIONAL INFORMATION PEACH BOTTOM ATOMIC POWER STATION. UNITS 2 AND 3 UNRESOLVED SAFETY ISSUE A-46
- 1.
The conservatism of the seismic margin methodology in the EPRI NP-6041
~
procedure is not certain at this time, when compared to the GIP-2 guidelines.
Its application is, therefore, not endorsed by the NRC for the analysis of safety-related system and components, including the resolution of USI A-46 mechanical, electrical, and structural component outliers. You are requested to reevaluate your USI A-46 program, if the above methodology has ever been used, and ensure that all the outliers
. identified in the Peach Bottom 2 & 3 A-46 program are resolved by using the plant licensing basis methodology or other approaches acceptable to the staff.
2.
Adequacy of Seismic Demand Determination (Ground Spectra and In-Structure / Floor Response Spectra)
Referring to the in-structure response spectra provided in~your 120-day-response to the NRC's request in Supplement No. I to Generic Letter (GL) 87-02, dated May 22, 1992, the following information is requested:
a.
Identify structure (s).which have ir.-structure response spectra (5%
critical damping) for elevations within 40-feet above the effective grade, which are higher in amplitude than 1.5 times the Seismic Qualification Users Group'(SQUG) Bounding Spectrum.
b.
With respect to the comparison of equipment seismic capacity and seismic demand, indicate.which method in Table 4-1 of GIP-2 was used to evaluate the seismic adequacy for equipment installed on the corresponding floors in the structure (s) identified in Item (a) above.
If you have elected to use method A in Table 4-1-of the
~
GIP-2, provide a technical justification for not using the in-structure response spectra provided in your 120-day-response.
It appears that some A-46 licensees are making an incorrect comparison between their pirit's safe shutdown earthquake (SSE) ground motion response spectrum and the SQUG Bounding Spectrum. The SSE ground motion response spectrum for most nuclear power plants is defined at the plant foundation level. The SQUG Bounding Spectrum is defined at the free' field ground surface. For plants located at deep soil or rock sites, there may not be a significant difference between the ground motion amplitudes at the foundation level and those at the free field ground surface. However, for sites where a structure is founded on shallow soil, the amplification of it.e ground motion from the foundation level to the ground surface may be significant.
c.
For the structure (s) identified in Item (a) above, provide the Enclosure f
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+ w suaz em.,qm es.sh ehusm awas-Ae..sas a in-structure response spectra designated according to the height above the effective grade.
If the in-structure response spectra identified in the 120-day-response to Supplement No. I to Generic Letter 87-02 was not used, provide the response spectra that were actually used to verify the seismic adequacy of equipment within the structures identified in Item (a) above. Also, provide a comparison of these spectra to 1.5 times the Bounding Spectrum.
3.
For those components listed in Table 4.2-1 of the Seismic Evaluation Report,- which are inaccessible during the walkdowns, the proposed methods of evaluation are based on general area walkdown, similarity to Unit 3 components, similarity to other components on the SSEL list, and drawings review.
You are requested to provide responses to the following comments:
a.
The general purpose of the equipment screening and walkdowns is to ensure the adequacy of the original seismic design; particularly, general installation, welded and embedded connections, and anchorages, as well as interaction concerns.
Explain how these objectives could be accomplished based on similarity to other components.
b.
Explain what is meant by "similar to Unit 3 components," and how the
" Unit ~3 Components" can be used for similarity comparison in i
walkdowns, if they are inaccessible as well.
c.
Provide a completion schedule for the evaluation of these inaccessible components, and the status of the resolution of the outliers, should they be identified by the proposed methods.
4.
As discussed in the attached relay evaluation report, the relay outliers have been resolved using the special exception contained in Section 4.2 of the GIP. You are requested to provide,_for staff review, a
. representative sample of resolutiora, which employed such special exception, as contained in Vectra Calculation No.. 0067-00084-C-021,
" Seismic Evaluation of PBAPS Relay," Rev.1, March 12,1996.
5.
The reference submittal states that all outlier resolutions, either by analysis, physical modifications, or administrative actions will be completed by December 31, 2000. You are requested to provide the justi-fication for assuring operability of the affected systems and components while a number of safety-related components in the safe shutdown path have been identified as outliers; thus rendering their seismic adequacy questionable and their conformance to the licensing basis uncertain, j
6.
In Attachment B, " Third Party Audit Report and Resume," to the Seismic Evaluation Report, it is stated that a third party performed a walkthrough audit of the plant.
~_
i-l 4 o
Clarify the scope and the extent of the walkthrough' activity. Since a.
no specific walkdown findings were obvious from the audit report, you are requested to clarify whether the audit has indeed included L
an independent plant walkdown for all the relevant A-46 equipment or has it merely served to echo the walkdown results already generated by the Seismic Review. Team (SRT).
The SRT walkdown results are summarized in Table 4.2-4 of the attached Seismic Evaluation Report.
i If an independent plant walkdown was not performed, provide the dccumentation to indicate that this third party audit has complied with the walkdown requirements of GIP-2.
b.
In Section 2.2 of Attachment B, it is stated that the third party has reviewed at least one of each equipment classes on the SSEL.
Explain how such a limited scope of review can lead to a general conclusion that Peach Bottom Units 2 & 3 are, "in general, well designed for seismic loads and that equipment installation appears to be quite rugged." Also provide the documents which support such review findings by the third party, c.
Explain the apparent conflict between the conclusion drawn in item (b) above, regarding equipment ruggedness, and the multiple evidences of component outliers listed in Table 4-2.4 of the Seismic Evaluation Report.
7.
Seismic Adequacy of Cable and Conduit Raceways
- a..You stated in reference I that you performed an evaluation of tha cable and conduit raceways in accordance with the GIP-2 guidelin9.
e i
However, during the recent review of another plant's implementation I
of the GIP-2 Guideline, the staff found that the procedure for i
ductile cable tray systems might not be sufficiently conservative.
The GIP-2 guideline stated that the ductile cable tray systems do not require an evaluation for lateral loads.
The staff does not fully-endorse this position and is currently pursuing a resolution of the' cable tray system ductility issue with SQUG (Reference 2). A generic resolution, when established, should apply to the Peach Bottom plant cable trays as well. At that time, you should revise the evaluation of the Peach Bottom cable tray systems accordingly.
For the interior of the cable spreading room, provide drawings of the cable tray systems and structures including drawings of the floor and/or ceiling at the elevations where the cable trays are attached. Also provide the. corresponding floor response spectra, including a discussion of how the flexibility of the floor was accounted for in constructing the spectra, and the final results of l
i the cable tray system evaluations in terms of deflections and associated stresses of the support systems.. Provide the weights of 4
l the cable trays and its contents, such as fire retardants, which l
were considered in the evaluations.
In addition, provide the f
r 1
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r validation documents of any computer codes or any analysis l
methodology which are used to produce the results discussed above.
i b.
You discussed the cable tray systems evaluation in Section 3.6.3.
Provide.a sample calcelation (including the methodology used) which j
involves the worst-case configurations of cable tray and conduit raceways from a safety margin point of view.
Provide the i
validation documents related to the evaluation. Also, provide a copy of reference 5.3.3, "Bechtel Cable Tray and Conduit Raceway Seismic Test Program, Volume I and II, September,1978," and explain l
how this reference was used in your evaluation. Discuss how the 1
cable and conduit raceway evaluations discussed in Section 3.6.3 differ from those in Section 4.4.
8.
Deviations from the GIP-2 Guideline In the summary report you stated that you are committed to implement the GIP-2, including the clarifications, interpretation, and exceptions in SSER-2, and to communicate to the NRC staff any significant or i
programmatic deviations from the GIP guidance.
You further stated that the submittal confirms that no significant or programmatic deviations 3
from the GIP guideline were made.
Provide the worst-case items (from the safety point of view) which l
l deviate from the GIP-2 guideline but were. categorized as not f
significant.
In addition, you are also requested to provide the l
definition of " safety significant," which were used by the walkdown L
personnel to categorize the deviations as either being significant or non-significant, and provide a justification that such a definition is adequate.
9.
Outlier Resolution l-In Section 4.6, titled " Description of Outliers," you provided a discussion on in-structure response spectra.
It is not clear why this was done.
Clarify whether these spectra are different from those submitted in'your 120-day response to Supplement No. I to Generic Letter 87-02.
If they are, provide a detailed justification for changing the spectra and explain how these spectra are used for equipment qualification (including the names of structures, elevatiens, and equipment,etc.). Also, provide the validation documents of the l
methodology used for constructing the spectra. Clarify whether these spectra are different from those discussed in Section 3.7.2.
t i
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REFERENCES 1.
Letter from G. Hunger, PECO, to NRC Document Control Desk, " Summary J
Report for Resolution of Unresolved Safety Issue (USI) A-46," dated May 7, 1996.
j 2.
Letter to D. Dorman, NRC, from N. P. Smith, Seismic Qualification Utility Group, "SQUG Generic Response to the Staff RAI," dated August 19, 1996.
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