ML20141A378
| ML20141A378 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 06/17/1997 |
| From: | Marcus G NRC (Affiliation Not Assigned) |
| To: | Jeffery Wood CENTERIOR ENERGY |
| References | |
| TAC-M94621, NUDOCS 9706200254 | |
| Download: ML20141A378 (7) | |
Text
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June 17,1997 Mr. John X. Wood DISTRIBUTION:
Docket File Vice President - Nuclear, Davis-Besse PD3-3 R/F PUBLIC Centerior Service Company ACRS JRoe c/o Toledo Edison Company EAdensam (EGA1)
OGC Davis-Besse Nuclear Power Station TMarsh, SPLB GGrant, RIII 5501 North State Route 2 JTatum, SPLB Oak Harbor, OH 43449-9760 SrJBJECT:
DAVIS-BESSE NUCLEAR POWER STATION, UNIT N0. 1 - ADDITIONAL l
CONCERNS REGARDING ULTIMATE HEAT SINK / SERVICE WATER TEMPERATURE (TAC N0. M94621)
Dear Mr. Wood:
i As discussed in our letter to you dated October 12, 1995, the NRC staff l
identified an apparent inconsistency between water temperature for the ultimate heat sink analysis and the service water system temperature used for containment response analysis following a loss-of-coolant accident.
You responded by letter dated January 31, 1996. By letter dated June 10, 1997, we requested that you meet with the NRC staff to discuss several issues which were identified as a result of the staff's review of your letter dated January 31, 1996.
To assist in your preparation for that meeting, the staff has prepared I
additional comments on your 1996 submittal, as documented in the enclosure.
Please contact Allen Hansen of my staff at (301) 415-1390 if you have any questions related to this issue.
Sincerely, l
Original signed by:
Gail H. Marcus, Director Project Directorate III-3 Division of Reactor Projects III/IV Office of Nuclear Reactor Regulation Docket No. 50-346
Enclosure:
As stated
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OFFICIAL RECORD COPY i
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PDR ADOCK 05000346 P
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June 17, 1997 l*
Mr. John K. Wood DISTRIBUTION:
Docket File Vice President - Nuclear, Davis-Besse PD3-3 R/F PUBLIC Centerior Service Company ACRS JRoe c/o Toledo Edison Company EAdensam (EGAl)
OGC Davis-~Besse Nuclear Power Station TMarsh, SPLB GGrant, RIII i
5501 North State Route 2 JTatum, SPLB Oak Harbor, OH 43449-9760
)
l
SUBJECT:
DAVIS-BESSE NUCLEAR POWER STATION, UNIT NO. 1 - ADDITIONAL CONCERNS REGARDING ULTIMATE HEAT SINK / SERVICE WATER TEMPERATURE (TAC N0. M94621) i
Dear Mr. Wood:
As discussed in our letter to you dated October 12, 1995, the NRC staff l
identified an apparent inconsistency between water temperature for the i
ultimite heat sink analysis and the service water system temperature used for j'
containment response analysis following a loss-of-coolant accident.
You responded by letter dated January 31, 1996.
By letter dated June 10, 1997, we requested that you meet with the NRC staff to discuss several issues which were identified as a result of the staff's review of your letter dated January 31, 1996.
To assist in your preparation for that meeting, the staff has prepared additional comments on your 1996 submittal, as documented in the enclosure.
Please contact Allen Hansen of my staff at (301) 415-1390 if you have any questions related to this issue.
j Sincerely, Original signed by:
Gail H. Marcus, Director Project Directorate III-3 i
Division of Reactor Projects III/IV j
Office of Nuclear Reactor Regulation l
Docket No. 50-346
Enclosure:
As stated cc w/ encl: See next page DOCUMENT NAME: G:\\DAVISBES\\DB94621.RAI OFFICE LA:PD3-3 l E PM:PD3-3 LE D:PD33 s
l NAME CBoyle 446 AHansen M J)
GMarcus 64 M l
DATE 6 / n/97 0 f /nA7 V 4//7/97 l
OFFICIAL RECORD COPY I
i i
anog$%
l g-UNITED STATES g
j NUCLEAR REGULATORY COMMISSION l
WASHINGTON, D.C. 20666-0001
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June 17, 1997 1
l Mr. John K. Wood Vice President - Nuclear, Davis-Besse Centerior Service Company c/o Toledo Edison Company Davis-Besse Nuclear Power Station 5501 North State Route 2 Oak Harbor, 0H 43449-9760 t
l
SUBJECT:
DAVIS-BESSE NUCLEAR POWER STATION, UNIT NO. 1 - ADDITIONAL i
CONCERNS REGARDING ULTIMATE HEAT SINK / SERVICE WATER TEMPERATURE (TAC N0. M94621)
Dear Mr. Wood:
As discussed in our letter to you dated October 12, 1995, the NRC staff identified an apparent inconsistency between water temperature for the l
ultimate heat sink analysis and the service water system temperature used for l
containment response analysis following a loss-of-coolant accident.
You responded by letter dated January 31, 1996. By letter dated June 10, 1997, we I
requested that you meet with the NRC staff to discuss several issues which l
were identified as a result of the staff's review of your letter dated January 31, 1996.
l To assist in your preparation for that meeting, the staff has prepared l
additional comments on your 1996 submittal, as documented in the enclosure.
l Please contact Allen Hansen of my staff at (301) 415-1390 if you have any questions related to this issue.
Sincerely, f
m Gail H. Marcus, Director Project Directorate III-3 Division of Reactor Projects III/IV Office of Nuclear Reactor Regulation Docket No. 50-346
Enclosure:
As stated cc w/ encl: See next page I
John K. Wood Davis-Besse Nuclear Power Station Toledo Edison Company Unit 1 cc:
Mary E. O'Reilly Robert E. Owen, Chief Centerior Energy Corporation Bureau of Radiological Health 300 Madison Avenue Service Toledo, Ohio 43652 0hio Department of Health P. O. Box 118 James L. Freels Columbus, Ohio 43266-0118 Manager - Regulatory Affairs Toledo Edison Company James R. Williams Davis-Besse Nuclear Power Station Chief of Staff 5501 North State - Route 2 Ohio Emergency Management Agency Oak Harbor, Ohio 43449-9760 2855 West Dublin Granville Road Columbus, Ohio 43235-2206 Gerald Charnoff, Esq.
Shaw, Pittman, Potts Roy P. Lessy,-Jr., Esq.
and Trowbridge Andrew G. Berg, Esq.
'2300 N Street, N.W.
Akin, Gump, Strauss, Hauer Washington, D.C.
20037
& Feld, L.L.P.
1333 New Hampshire Ave., NW, Ste. 400 Regional Administrator Washington, D.C.
20036 U.S. NRC, Region III 801 Warrenville Road Ohio Environmental Protection Agency Lisle, Illinois 60523-4351 DERR--Compliance Unit ATTN:
Zack A. Clayton Robert B. Borsum P. O. Box 1049 Babcock & Wilcox Columbus, Ohio 43266-0149 Nuclear Power Generation Division 1700 Rockville Pike, Suite 525 State of Ohio Rockville, Maryland 20852 Public Utilities Commission 180 East Broad Street Resident Inspector Columbus, Ohio 43266-0573 U. S. Nuclear Regulatory Commission 5503 North State Route 2 Attorrey General Oak Harbor, Ohio 43449 Department of Attorney 30 East Broad Street James H. Lash, Plant Manager Columbus, Ohio 43216 Toledo Edison Company Davis-Besse Nuclear Power Station President, Board of County 5501 North State Route 2 Commissioner of Ottawa County Oak Harbor, Ohio 43449-9760 Port Clinton, Ohio 43252 l
Donna Owens, Director Ohio Department of Commerce Division of Industrial Compliance
(
Bureau of Operations and Maintenance 6606 Tussing Road i
P.O. Box 4009 l
Reynoldsburg, Ohio 43068-9009 i
i
l REVIEW 0F THE DAVIS-BESSE ULTIMATE HEAT SINK BY THE OFFICE OF NUCLEAR REACTOR REGULATION l
l LNTR000CTION The licensee for the Davis-Besse Nuclear Power Station (DBNPS) has asserted that Lake Erie, along with the intake canal and the seismic Class I intake forebay area, form the Ultimate Heat Sink (VHS) for safe shutdown and accident a
mitigation purposes for DBNPS.
In a letter dated January 31, 1996, to the NRC, the licensee stated that "the overall plant design and licensing basis for DBNPS regarding seismic events and Loss-of-Coolant Accidents (LOCA) is that a seismic event is not postulated to occur concurrently with a LOCA." On this basis, the licensee maintains that it is not necessary to rely solely on the seismic Class I intake forebay to mitigate a LOCA and that the licensing basis of the plant credits Lake Erie, the intake canal, and the intake forebay for satisfying the UHS function during a LOCA.
ASSESSMENT While the NRC staff agrees that Lake Erie, along with the intake canal and the seismic Class I intake forebay area, form the UHS for normal power operation, the licensing basis for DBNPS appears to s)ecifically credit use of the seismic Class I section of the intake foreaay area as the UHS for mitigation of the design-basis LOCA. The staff's view is supported by information that was submitted by the licensee during NRC review of the licensee's Application for License for DBNPS and by the staff's licensing SER, as discussed below.
j DBNPS Final Safety Analysis Reoort (FSAR). throuah Amendment No. 41 to the l
Acolication for Licenses. dated December 16. 1976 e The licensee's response to FSAR Question 9.2.8 on this subject assumed that only the seismic Class I section of the intake forebay was available in the LOCA heat load analysis.
e Section 2.4.8.2 of the FSAR stated, "The intake canal forebay is designed as seismic Class I, and will be used as a heat sink reservoir during accident and maximum possible (larger) earthquake."
e Section 3.2.1.1 of the FSAR stated " Class I structures, systems, and components for seismic design purposes are defined as those structures, systems, and components important to safety that are designed to remain functional in the event of a maximum possible earthquake. These si.rectures, systems, and components are those necessary to ensure:
a.
The integrity of the reactor coolant pressure boundary:
b.
The capability to shut down the reactor and maintain it in a safe
{
shutdown condition; or i
k j
ENCLOSURE l
i i'
, c.
The capability to prevent or mitigate the consequences of accidents which could result in potential offsite exposures comparable to the guideline exposures of 10 CFR Part 100."
Lake EMe and the intake canal are not Class I structures and do not satisfy this criteria, especially that stated in (c) above.
- Section 3.2.1.2 o' the FSAR stated. " Structures, systems, and equipment classifisd as Class I are those whose failure could cause the uncontrolled release of radioactivity and/or are essential for immediate and long-term operation following a maximum possible earthquake." The intake forebay area is the only seismic Class I structure that can be credited in this regard.
e Section 3.7.2.10 of the FSAR stated. "The intake canal forebay, approximately 700 feet long, impounds a body of water that serves as a heat sink."
Section 3.8.1 of the FSAR included the intake structure in the listing of e
Class I structures outside containment: Lake Erie and the intake canal were not included in the listing of Class I structures.
l e Section 9.2.1 of the FSAR pertaining to the service water system stated.
l "The portion of the system required for emergency operation, including the intake structure is designed to the ASME Code.Section III, Nuclear Class 3 and Seismic Class I, as applicable." Lake Erie and the intake canal are not seismic Class I and, therefore, were not intended to be relied upon for emergency operation.
I e The discussion in the FSAR pertaining to Criterion 2 of the General Design l
Criteria stated. " Structures, systems and components important to safety are designed to withstand the effects of natural phenomena such as earthquakes, tornadoes, hurricanes. floods, wind tides, and seiches without loss of capability to perform their safety functions."
NUREG-0136. the Safety Evaluation Reoort (SER) for 08NPS. Unit 1:
l e Section 2.4.3 of the SER states:
"The ultimate heat sink for the Davis-l Besse. Unit 1 facility consists of the water supply contained in the i
seismic Category I intake forebay area (approximately 700 feet long) plus the water volume retained in a e assumed failed configuration of the 3.000-foot long, non-seismic Category I intake canal between the forebay and Lake Erie. The assumed failure of the non-seismic portion of the intake canal results in a loss of two-thirds of the initial volume in the canal and isolates the facility from Lake Erie."
e Section 3.2.1 of the SER states:
" Structures, systems and components important to safety that are required to be designed to withstand the effects of a safe shutdown earthcuake and remain functional have, in general, been properly classifiec as seismic Category I items.
These
l 1.
3-i facility features are those necessary to assure:
(1) the integrity of the reactor coolant pressure boundary: (2) the capability to shutdown the reactor and maintain it in a safe shutdown condition: or (3) the capability to prevent or mitigate the consequences of accidents which could result in potential offsite exposures comparable to the guidelines of 10 CFR Part 100." Lake Erie and the intake canal do not satisfy this criteria.
l CONCLUSION The staff is concerned that containment cooling during the design-basis LOCA and the basis for equipment qualification may not be consistent with the plant's licensing basis.
In general, systems that are relied upon for LOCA mitigation must satisfy seismic Class I requirements.
This is a design requirement that was imposed by the NRC to provide assurance of system capability irrespective of whether or not a seismic event has occurred.
Based on the information reviewed by the staff and discussed above, it appears that the UHS for DBNPS for LOCA mitigation should only consist of the seismic Class I section of the intake forebay area along with one-third of the water volume contained in the non-seismic intake canal.
Lake Erie provides cooling water for normal power operation of the facility, but should not be credited for accident mitigation.
If these conclusions are correct. then the containment performance analysis for DBNPS does not adequately reflect the cooling that will be provided by the UHS. and the equipment qualification basis is in error.
1 Principal Contributor:
J. Tatum, SPLB Date:
June 17, 1997 l
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