ML20217N034
| ML20217N034 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 03/27/1998 |
| From: | Stolz J NRC (Affiliation Not Assigned) |
| To: | Smith N SEISMIC QUALIFICATION UTILITY GROUP |
| References | |
| REF-GTECI-A-46, REF-GTECI-SC, TASK-A-46, TASK-OR GL-87-02, GL-87-2, NUDOCS 9804080302 | |
| Download: ML20217N034 (7) | |
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UNITED STATES y
NUCLEAR RE2ULATORY COMMISSION 2
WASHINGTON, D.C. ma anat F'
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l March 27, 1998 Mr. Neil Smith, Chairman Seismic Qualification Utility Group clo MPR Associates,lnc.
320 King Street l
Alexandria, VA 22314
Dear Mr. Smith:
This is in response to the Seismic Qualification Utility Group (SQUG) letters of January 22 and 26,1998, regarding the SQUG concerns with NRC's recently issued requests for additional information (RAls) to SQUG members and the Nuclear Regulatory Commission's (NRC) approach to the Unresolved Safety issue (USI) A-46 (Verification of Seismic Adequacy of Mechanical and Electrical Equipment in Operating Reactors) closure process. This is also a
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follow up to a telephone conversation held on March 19,1998, between Mr. Wessman and Mr.
Manoly of the NRC and yourself and Mr. John Butler of the Nuclear Energy Institute (NEI).
As you are aware, except for Millstone Unit 1, all the licensee summary reports, documenting licensee actions to address USI A-46 have been submitted and are under staff review. The staffs review is to allow NRC to make an assessment of licensee USI A 46 actions for consistency with SQUG's Generic implementation Procedure, Revision 2 (GlP-2) and the staffs Supplemental Safety Evaluation Report (SSER) of GIP-2, issued on May 22,1992, with Generic Letter (GL) 87-02, Supplement 1. Censistent with GL 87 02, the staff intends to issue a site-specific SER for each USI A-46 facility. In the course of the staffs review, RAls have been issued to SOUG member licensees. The staffs focus in these RAls has been to clarify site specific situations or individuallicensee actions addressing USl A-46; however, as detailed in i
your January 26,1998, letter, SQUG believes, in four generic areas, "the staff is using the RAI process to re-review the criteria and guidelines in the GlP which have already been accepted by the NRC in Supplemental Safety Evaluation Report No. 2 (SSER No. 2)." The staff does not i
view the RAI process as a re-review of the GIP, and our response to each of SQUG's four generic issues is provided in the enclosure to this letter.
The NRC plans to move expeditiously towards closure of the USI A-46 issue and has committed substantial resources to this effort. Each plant specific SER will provide an assessment of the licensee's submittalin response to the NRC's request for information under the provisions of 10 CFR 50.54(f), made as part of GL 87-02. Each SER will address the following:
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- description of the submittal within the A-46 scope f' ~ l
- areas where, in the staffs judgement, the licensee met GIP-2 and the staffs May 22,1992 Li SSER fi 7& 7/
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- areas where, in the staffs judgement, the licensee did not fully meet GIP-2 and the staffs t.)
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- whether or not the licensee has completed outlier disposition or provided a schedule for outlier 1
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- whether or not the licensee identified any operability concems, and
- actions the licensee would have to take to incorporate GIP-2 into the licensing basis for the facility.
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Where the staff has determined that the licensee's implementation of USl A-46 has met the provisions of 10 CFR 50.54(f), the SER will conclude that the licensee's USl A-46 implementation program has, in general, met the purpose and intent of the criteria in GIP-2 and the staff's generic SSER No. 2, and that there is sufficient basis to close USl A-46 at that facility. In these SERs, the staff expects to be able to conclude that the licensee's already completed actions and commitments to complete the disposition of remaining outliers will result in safety enhancements, in certain aspects, that are beyond the originallicensing basis of the facility.
U.Sl A-46 SERs for the first group of plants reviewed by the staff should be issued within the next 1-2 months. The staff expects to move expeditiously with the A-46 reviews with a target that most reviews will be complete by mid-1999.
Please contact Richard H. Wessman, Chief of the Mechanical Engineering Branch, at (301) 415-3288, if you have any questions.
1 Sincerely,
/s/
John F. Stolz, Director Project Directorate 1-2 Division of Reactor Projects - 1/11 i
Office of Nuclear Reactor Regulation
Enclosure:
NRC Staff Response I
- cc w/ encl: Mr. R. Kassawara, EPRI Mr. John Butler Electric Power Research Institute Nuclear Energy Institute -
3412 Hillview Avenue..
Suite 400 P.O. Box 10412
- 1776 i Street, NW..
Palo Alto, CA 94304 Washington, DC 20006-3708 i
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t Where the staff has determined that the licensee's implementation of USl A-46 has met the provisions of 10 CFR 50.54(f), the SER will conclude that the licensee's USI A-46 implementation piogram has, in general, met the purpose and intent of the criteria in GIP-2 and the staff's generic SSER No. 2, and that there is suWicient basis to close USl A-46 at that facility. In these
~ SERs, the staff expects to be able to conclude that the licensee's already completed actions and commitments to complete the disposition of remaining outliers will result in safety enhancements, in certain aspects, that are beyond the original licensing basis of the facility.
USl A-46 SERs for the first group of plants reviewed by the staff should be issued within the next 1-2 months. The staff expects to move expeditiously with the A-46 reviews with a target that most reviews will be complete by mid-1999.
Please contact Richard H. Wessman, Chief of the Mechanical Engineering Branch, at (301) 415-3288, if you have any questions.
Sincerely,
/s/
John F. Stolz, Director Project Directorate 1-2 Division of Reactor Projects - 1/11 Office of Nuclear Reactor Regulation
Enclosure:
NRC Staff Response cc w/ encl: Mr. R. Kassawara, EPRI Mr. John Butler Electric Power Research Institute Nuclear Energy Institute j
3412 Hillview Avenue Suite 400 1
P.O. Box 10412 1776 l Street, NW Palo Alto, CA 94304 Washington, DC 20006 3708 DISTRIBUTION Central File GLainas GBagchi PUBLIC RWessman POI-2 Reading GMizuno JStolz EMEB Reading /Chron RCapra KManoly DDorman RRothman OFFICE ABO,m -
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DATE 3 /2 7/98 h/bh8 7 N /98 J
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DOCUMENT NAME: SQUG0498
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N. Smith Where the staff has determined that the licensee's implementation of USl A-46 has met the provisions of 10 CFR 50.54(f), the SER will conclude that the licensee's USl A-46 implementation -
program has, in general, met the purpose and intent of the criteria in GIP-2 and the staff's generic SSER No. 2, and that there is sufficient basis to close USl A-46 at that facility, in these SERs, the staff expects to be able to conclude that the licensee's already completed actions and commitments to complete the disposition of remaining outliers will result in safety enhancements, in certain aspects, that are beyond the originallicensing basis of the facility, l
USl A-46 SERs for the first group of plants reviewed by the staff should be issued within the next 1-2 months. The staff expects to move expeditiously with the A-46 reviews with a target that most reviews will be complete by mid 1999.
Please contact Richard H. Wessman, Chief of the Mechanical Engineering Branch, at (301) 415-3288, if you have any questions.
Sincerely,
- 1
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n F. Stolz, Director Project Directorate 12 Division of Reactor Projects 1/11 Office of Nuclear Reactor Regulation
Enclosure:
NRC Staff Response cc w/enci: Mr. R. Kassawara, EPRI Mr. John Butler j
Electric Power Research Institute Nuclear Energy Institute 3412 Hillview Avenue Suite 400 P.O. Box 10412 1776 i Street, NW Palo Alto, CA 94304 Washington, DC 20006-3708 1
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i STAFF RESPONSE TO SEISMIC QUALIFICATION UTILITY GROUP CONCERNS 1.
Use of Ground Resoonse Soectra for Estimatino Seismic Demand The staffs RAls to SQUG members have stated the staffs concern with the licensees' selection of demand spectra, have pointed out the cautions applicable in the event a licensee chooses to apply Method "A" of the GIP, and (in some cases) have requested the licensee to justify its selection of the demand spectra. In cases where a licensee elected to use different spectra than that provided by the licensee in its 120-day response to GL 87 02, Supplement No.1, the staff has requested the licensee to provide a basis for their decision. SQUG has taken the position that (1) a licensee submittal of the in-structure response spectrum (IRS)in its 120-day response did not imply a commitment to use the IRS exclusive of Method A, (2)
Method A is an attemative to Method B for elevations up to 40 feet from plant-grade level, (3) there is no requirement to use the more conservative of Method A or Method B, and (4) the GIP-2 cautionary paragraph (Pg 4-16 of GIP-2) is only to alert the seismic review team not to use Method A for atypical nuclear power plant structures.
The staff does not agree with SQUG, for reasons previously provided in our letter of December 2,1997. The staff expects that the licensee must have a basis for the selection of a demand spectra and that the basis should include consideration of site-specific factors such as soil, the plant structure, the equipment location and natural frequency, and the availability of an IRS. Site-specific situations cannot be disposed of solely on the basis of generic arguments. The justification for the inclusion of Method A in the GIP was that, for stiff structures such as those used in nuclear power plants, the amplification of the ground response spectrum up to the elevations of about 40 feet above plant-grade level would be approximately 1.5 and that the original design bases IRS are overly conservative. We have found in our A-46 summary report reviews that the IRS developed specifically for this program using the latest modeling and analytical techniques can indicate amplifications greater than 1.5 at elevations below 40 feet. However, to move forward on the USI A-46 closure process, the staff intends to proceed as follows:
The staff is reviewing the use of Method A on a case-by-case basis and where a licensee provides an appropriate justification, its use will be acceptable.
- Where a licensee's summary report indicates the use of a demand spectrum other than the licensing basis or that described in the 120-day response, the staff will continue to seek additionalinformation regarding the methodology employed for developing the new spectrum, if the basis for the methodology was not provided.
Where a licensee's summary report indicates the selection of a different demand spectrum than that provided in the 120-day response, and sufficient information is provided regarding the methodology employed for developing the spectrum, the staff will not seek additional information on this issue.
If, in the staffs judgement, the licensee's use of Method A is not shown to be adequately justified, the staff will document this finding in the USI A-46 SER.
ENCLOSURE
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- 2. Lateral Load Ductility Evaluation of Cable Travs On a site-specific basis, the staff has questioned the licensee's application of the GIP methodology with regard to the assumption of ductility of cable tray and raceway supports.
4 The staff has questioned the basis for performing a limited analytical review and has asked.
1l various plant specific questions regarding the evaluation of cable trays. SQUG believes certain of the staff questions are generic in nature and provided with its January 22,1998,
' letter, additional materialin support of the GIP-2 guidelines for the verification of cable tray seismic adequacy.
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The staff reviewed and accepted the approach provided in GlP-2, The staff concern is not necessarily with the GlP-2 concept, but rather with the way it has been employed by some licensees. Consequently, licensees have been asked to explain their bases for
~ determinations made during plant walk downs that cable tray and raceway supports are ductile; The staff accepts SQUG's position that cable tray and raceway supports in the data base are inherently rugged because they generally behaved in a ductile manner. However, for A-46 plants with cable tray or raceway configurations which are not in the. experience database or those with obviously rigid support configurations the staff will continue to ask plant specific questions regarding a licensee's basis for their ductility determinations. These plant specific aspects cannot be addressed generically.
- 3. Seismic Adeauaev of Relavs Mounted on Diesel Generators and Air Comoressors At one facility (Point Beach) the staff requested the licensee to justify its basis for relay operability for certain relays mounted in control cabinets anchored on a common skid with a -
diesel generator or air compressor. SQUG. assumed this was a generic issue and expressed concern that the staff was taking issue with the provision to accept relays mounted on equipment such as diesel generators and air compressors.
1 This original question was focused at relays in control cabinets anchored to a common skid with the diesel generator or air compressor, as opposed to relays mounted directly on the equipment. This issue has not been identified at any other facility and the Point Beach
- licensee has agreed in its response of July 31,1997, to reexamine the staff's original concern. The staff believes this issue is closed.
- 4. Justification for Schedules to Resolve GIP Outliers Staff RAls have asked licensees about their schedules to resolve indeterminate outliers and -
have inquired if licensees have addressed possible operability issues. SQUG stated in its
' letter of January 26,1998, that licensees are committed to perform a seismic adequacy review and report the results to the NRC in response to the NRC's 50.54(f) information request. SQUG reminds NRC that, as stated in NUREG-1211 (Regulatory Analysis for Resolution of Unresolved Safety issue A 46, Seismic Qualification of Equipment in Operating Plants, February 1987) a backfit analysis for the correction of any deficiency will be performed on a case-by-case basis if required.
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.q 3-l The staff agrees with SQUG that licensees would not have to correct A-46 outliers unless there are situations where the plant does not meet the licensing basis. Licensees would be expected to report and address these situations under existing regulations. The staff's RAls j
have been a consequence of uncertainty whether a licensee has addressed all aspects relating to indeterminate outliers. The staff will assume that licensees addressed operability issues as part of the walkdown process and that they continue to assess operability issues during routine plant operations. When such issues are identified, the staff continues to expect that licensees will follow appropriate reporting and corrective action processes. It l
should be noted however, since some licensees have indicated that they plan to incorporate l
the GIP in their Final Safety Analysis Report (FSAR), it is important that, for these licensees, l
all relevant outliers be addressed prior to proceeding with the FSAR change.
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