ML20198F941
| ML20198F941 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 12/18/1997 |
| From: | Mcdonald D NRC (Affiliation Not Assigned) |
| To: | Bowling M NORTHEAST NUCLEAR ENERGY CO. |
| References | |
| TAC-M99266, NUDOCS 9801120214 | |
| Download: ML20198F941 (6) | |
Text
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Mr. M;rtin L. Bowling Recov:ry Officer - Millstone Unit No. 2 December 18, 1997
- k _'
N.rthe:st Nucle:r Energy Comp:ny c
clo Ms. Patricia A. Loftus Director - Regulatory Affairs P. O. Box 128 Waterford, Connecticut 06385
SUBJECT:
CORRECTION TO LETTER DATED AUGUST 19,1997, AND ENCLOSED SAFETY EVALUATION - MILLSTONE NUCLEAR POWER STATION, UNIT NO. 2 (TAC NO. M99266)
Dear Mr. Bow 0ng:
By "B16339, Submits Update to Response to RAI Question 3 Re GL 95-07, Pressure Locking & [[Topic" contains a listed "[" character as part of the property label and has therefore been classified as invalid. of SR Power-Operated Gate Valves. Commitments Provided in Attachment 1|letter dated June 23,1997]], Northeast Nuaar Energy Company (NNECO) indicated that it had determined to continue to operate without a HIGH Startup Rate (SUR) trip. By letter dated August 19,1997, we provided a Safety Evaluation (SE) indicating that continued operation of Millstone, Unit 2, without a SUR trip continues to be acceptable to the NRC staff.
However, it has been brought to our attention that inaccurate statements had been mado in the letter and supporting SE. Specifically, we indicated in the letter that it had been confirmed that the unit was operated outside the assumptions of its nafety analysis for Cycles 1 and 2. This should have indicated Cycles 2 and 3. We further noted that on page 2 of the SE the word
" maximizes' in the phrase "...the lowest possible reactor coolant system (RCS) pressure (which maximizes the...[DNB])" should have been " minimizes."
We appreciate yuur staff bringing this to our attention. We request that you retain a copy of this correction letter with the August 19,1997, letter and enclosed SE.
We apologize for any inconvenience resulting in these administrative errors. If there are any i
questions please contact me on (301) 415-1408.
Sincerely, Original signed by:
Daniel G. Mcdonald Jr., Sr. Project Manager 9001120214 971218 Special Projects Office - Licensing Office of Nuclear Reactor Regulation LYM DR ADOCK 050003 6
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Docket No. 50-336 i
Enclosures:
As stated
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- wasuswovow, o.c. somewen Deced=r 18, 1997 Mr. Martin L. Bowling Recovery Officer - Millstone Unit No. 2 Northeast Nuclear Energy Company clo Ms. Patricia A. Loftus Director-Regulatory Affairs P. O. Box 128 Waterford, Connecticut 06385
SUBJECT:
' CORRECTION TO LETTER DATED AUGUST 19,1997, AND ENCLOSED SAFETY EVALUATION - MILLSTONE NUCLEAR POWER STATION, UNIT NO. 2 (TAC NO. M99266)
Dear Mr. Bowling:
t By "B16339, Submits Update to Response to RAI Question 3 Re GL 95-07, Pressure Locking & [[Topic" contains a listed "[" character as part of the property label and has therefore been classified as invalid. of SR Power-Operated Gate Valves. Commitments Provided in Attachment 1|letter dated June 23,1997]], Northeast Nuclear Energy Company (NNECO) indicated that i.
had determined to continue to operate without a HIGH Startup Rate (SUR) trip. By letter dated 3~
August 19,1997, we provided a Safety Evaluation (SE) indicating that continued operatinn of Millstone, Unit 2, without a SUR trip continues to be acceptable to the NP.C staff.
However, it has been brought to our attention that inaccurate statements had been made in the letter and supporting SE. Specifically, we indicated in the letter that it had been confirmed that the unit was oporated outside the assumptions of its safety analysis for Cycles 1 and 2. This
. should have indicated Cycles 2 and 3. We further noted that on page 2 of ths SE the word
- maximizes
- in the phrase "...the lowest possible reactor coolant system (RCS) pressure (which maximizes the...[DNB])'should have been " minimizes."
l-We appreciate your staff bringing this to our attention. We request that you retain a copy of this corredion letter with the Au,,ust 19,1997, letter and enclosed SE.
L We apologize for any 'nconvenience rasulting in these administrative errors, if there are any questions please contact me on (301) 415-1408.
Sincerely, 0
. _0 Daniel G. Mcdonald Jr., Sr. Project Manager Special Projects Office - Licensing Office of Nuclear Reactor Regulation l
i-Docket No. 50-336 r
Enclosures:
' As stated l
cc w/encis:;See next page l
l
~
~ -
+
l Northeast Nuclear Energy Company Millstone Nuclear Power Station ff Unit 2 CC' Ernest C. Hadley, Esquire Lillian M. Cuoco, Esquire 1040 B Main Street Senior Nuclear Counsel P.O. Box 549 Northeast Utilities Service Company West Wareham, MA 02576 P. O. Box 270 Hartford, CT 06141-0270 Mr. D. M. Goebel Vice President - Nuclear Oversight M.'. John Buckingham Northeast Utilities Service Company Department of Public Utility Control P. O. Box ??8 Electric Unit Waterford, CT 06385 10 Liberty Square New Britain, CT 06051 Mr. David Amerine Vice President - Nuclear Engineering i,
Mr. Kevin T. A. McCarthy, Director and Support Monitoring and Radiation Division Northeast Utilities Service Company Cepartment of Environmental Protection P. O. Box 128 79 Elm Street Waterford, CT 06385 Hartford, CT 06106-5127 Mr. Allan Johanson, Assistant Director Regional Administrator, Region I Office of Pslicy and Management U.S. Nuclear Regulatory Commission Policy Deve'opment and Planning 475 Allendale Road Division Xing of Prussia, PA 19406 450 Capitol Avenue - MS# 52ERN P. O. Box 341441 First Selectmen Hartford, CT 06134-1441 lown of Waterford Hall of Records Mr. M.
H.
Brothers 200 Boston Post Road Vice President - Operations Waterford, CT 06385 Northeast Nuclear Energy Company P.O. Box 128 Mr. Wayne D. Lanning Waterford, CT 06385 Deputy Director of Inspections Special Projects Office Mr. J.
A.
Price 475 Allendale Road Unit Director - Millstone Unit 2 King of Prussla, PA 19406-1415 Northeast Nuclear Energy Company P.O. Box 128 Charles Brinkman, Manager Waterford, CT 06385 Washington Nuclear Operations ABB Combustion Engineering Mr. B.
D.
Kenyon 12300 Twinbrook Pkwy, Suite 330 Chief Nucler Officer - Millstone Rockville, MD 20852 Northeast Nuclear Energy Company P.O. Box 128 Senior Resident Inspector Waterford, Cl 06385 Millstone Nuclear Power Station c/o U.S. Nuclear Power Station Citizens Regulatory Commission P.O. Box 513 ATTN: Ms. Susan Perry Luxton Niantic, CT 06357 180 Great Neck Road Waterford, Connecticut 06385 Mr. F. C. Rothen Vice President - Work Services Northeast Utilities Service Company P. O. Box 128 Waterford, CT 06385 4
t Northeast Nuclear Energy Company Millstone Nuclear Power Station Unit 2 cc:
g Deborah Katz, President Citizens Awareness Network P. O. Box 83 Shelburne Falls, MA 03170 The Honorable Tucry Concannon r,o. Chair Nuclear Energy Advisory Council Room 4035 Legislative Office Building Capitol Avenue Hartford, Connecticut 06106 Mr. Evan W. Woo 11acott Co-Chair Nuclear Energy Advisory Council 128 Terry's Plain Road Simsbury, Connecticut 06070 Little Harbor Consultants, Inc.
Millstona - ITPOP Project Office P. O. Box 0630 Niantic, Cornecticut 06357-0630 Mr. Daniel L. Curry Project Director Parsons Power Group Inc.
'2675 Morgantown Road Reading, Pennsylvania 19607 Mr. Don Schopfer Verification Team Manager Sargent & Lundy 55 E. Monroe Street Chicago, Illinois 60603 4
__._.____m.______i.-__________----______
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UNITED STATES NUCLEAR R T
WSSION August 19, 1997 s
Mr. Neil S. Carns Senior Vice President snd' Chief Nuclear Officer L M heast Nuclear Energy Company c/o Ms. Patricia A. Loftus-Director - Regulatory Affairs P.D. Box 128 Waterford, CT 06385 i
SUBJECT:
CONTINUED OPERATION WITHOUT A HIGH STARTUP RATE TRIP -
MILLETONE NUCLEAR POWER STATION, UNIT NO. 2 (TAC Wu.-M99266)
Dear Mr. Carns:
Py. "B16339, Submits Update to Response to RAI Question 3 Re GL 95-07, Pressure Locking & [[Topic" contains a listed "[" character as part of the property label and has therefore been classified as invalid. of SR Power-Operated Gate Valves. Commitments Provided in Attachment 1|letter dated June 23, 1997]] Northeast Nuclear Energy Com)any (NNECO) indicated that it had determined to continue to operate wit 1out a High Startup Rate (SUR) trip.. The NRC staff approved removal of the SUR trip in Amendment No. 38 to Facility Cperating License No. DPR-65 for the Millstone Nuclear Power Station, Unit 2, on April 19, 1978, based on NN M 's request, which was supported by Combustion Engineering.
However, as noted in your letter, NNEr? informed the NRC in Licensee Event Report (LER) 50-336/90-029-09, dated hptember 16, 1996, that the removal resulted in Millstone, Unit 2, operating outside the assumptions of its safety analysis during Cycles 2 and 3.
it was further indicated in the supplemental LER 50-336/96-029-01,. dated June 3, 1997, that-additional investigation confirmed that the untt_E g erated outside the assumptions of its safety analysis for 6clesland N AsubsequentanalysthperformedbySiemensPowerCorporation-(SPC),whichwas approved by the NRC, recognized the removal of the SUR trip and did not credit
-it for protection from a control element assembly (CEA) withdrawal' event initiated from subcritical conditions. However, as the iesult of the followup investigations NNECO determined that two errors existed in the SPC analysis and requested that SPC perform a new analysis, which was provided to the NRC staff-as-an enclosure to the June 23,-1997, letter.
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most limiting CEA insertion configuration (which maximizes the axial)andtne kwes radial p>wer peaking and the CEA bank reactivity worths), and the lowest possible reactor ::colant system (RCS) pressure (which ma_ximizas the margin to.
departure-from-nucleate-boiling [DNB?).
Based on this, Initration curing 'P n f Mode 3 is more limiting than initiat on daring Mode 2.
Therefore, the event was initiated during Mode 3 for the analysis. The analysis also assumed a conservatively small negative Doppler coefficient and the most positive moderator coefficient allowed by the Millstone, Unit 2. TSs.
The event initiator was assumed to be a single failure, which causes the sicontrolled withdrawal of al
- equence and overlap from 10',1 regulating cia banks, in the normal withdrawal of rated power at a conservatively fast withdrawal rate of 50 in./ min. This is acceptable because the CEAs are wired together into preselected bank configurations, which prevent them from being withdrawn in other than their respective banks.
Power is supplied to the banks in such a way that no more than two banks can be withdrawn at the same time and in their proper withdrawal atocence. The analysis further assumed that the event is preceded by an estent i shutdown, which maximizes the power overshoot, and also occurs at a beginninpof-c.ycle condition, which minimizes the negative Doppler feedback. Bnh of these assumptions are conservative and, therefore, acceptable.
The transient is terminated by the V0P trip with a minimum DNB ratio of 1.50, well above the 95/95 safety limit of 1.17 for the XNB DNB correlation. The peak fuel centerline temperature reaches 2521*F, well below the fuel melting temperature of UO,.
Therefore, the requirements of General Design Criterion (GDC) 20, that protection be automatically initiated, and GDC 25, that a single failure of the protection system does not result in violation of specified acceptable fuel design limits, have been satisfied.
3.0 CONCLUSION
The NRC staff has reviewed the revised analysis for Millstone Unit 2 during Cycles 10 through 13 and has concluded that the V0P trip provides acceptable fuel protection against exceeding DNBR or fuel centerline melt limits.
Therefore, the NRC staff agrees with NNECO's conclusion that continued operation of Millstone, Unit 2, without the SUR trip is acceptable for future cycles that are bounded by the conditions of the SPC reanalysis as documented in Siemens Report EMF-97-014, Rev 0, " Millstone Unit 2 Uncontrolled CEA Bank Withdrawal from Subcritical/startup Analysis," dated February 1997.
Principal Contributor: L. Kopp Date: August 19, 1997
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