ML14119A187
| ML14119A187 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 04/23/2014 |
| From: | Mark D. Sartain Dominion, Dominion Nuclear Connecticut |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 14-172 | |
| Download: ML14119A187 (5) | |
Text
Dominion Nuclear Connecticut, Inc.
iEDominion 5000 Dominion Boulevard, Glen Allen, VA 23060 Web Address: www.dom.com April 23, 2014 U. S. Nuclear Regulatory Commission Serial No.14-172 Attention: Document Control Desk NSSL/MLC RO Washington, DC 20555 Docket No.
50-423 License No.
NPF-49 DOMINION NUCLEAR CONNECTICUT, INC.
MILLSTONE POWER STATION UNIT 3 SUPPLEMENT TO LICENSE AMENDMENT REQUEST FOR CHANGES TO TECHNICAL SPECIFICATION 3/4.7.5. "ULTIMATE HEAT SINK" By letter dated May 3, 2013, Dominion Nuclear Connecticut, Inc. (DNC) submitted a license amendment request (LAR) for Millstone Power Station Unit 3 (MPS3).
The proposed amendment would modify Technical Specification (TS) 3/4.7.5, "Ultimate Heat Sink," to increase the current ultimate heat sink (UHS) water temperature limit from 75°F to 80'F and change the TS Action to state, "With the ultimate heat sink water temperature greater than 800F, be in HOT STANDBY within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />." DNC requested approval of the LAR by May 5, 2014 with implementation within 60 days of issuance. A supplement to the LAR was provided to the NRC in a letter dated July 2, 2013. Additionally, DNC responded to two requests for additional information in letters dated October 2, 2013 and January 15, 2014.
Recent DNC review of a vendors' calculation which was done in support of the UHS LAR identified a non-conservative error in the calculation involving the service water to control building chilled water cross tie. This error specifically impacts the discussion provided in Attachment 1, Section 5.3.2.3, "Building Air Conditioning Water Chillers (3HVK*CHL 1 A/B)," of the LAR submittal dated May 3, 2013.
The attachment to this letter provides an updated discussion of this section with the additional information highlighted in bold font style. The updated discussion continues to support the LAR submittal for the 80°F ultimate heat sink temperature.
If you have any questions or require additional information, please contact Wanda Craft at (804) 273-4687.
Sincerely, ViCKI L. HULL Mak DNotary Public Mark D. Sartain
]
Commonwealth of Virginia
[
Vice President - Nuclear Engineering 140542 r
1 MY Commission Expires may 31, 2014 COMMONWEALTH OF VIRGINIA 2014 COUNTY OF HENRICO The foregoing document was acknowledged before me, in and for the County and Commonwealth aforesaid, today by Mark D.
Sartain, who is Vice President - Nuclear Engineering of Dominion Nuclear Connecticut, Inc. He has affirmed before me that he is duly authorized to execute and file the foregoing document in behalf of that Company, and that the statements in the document are true to the best of his knowledge and belief.
Acknowledged before me this fday of.4A P 0-L
,2014.
My Commission Expires:
Notary Public
Serial No.14-172 Docket No. 50-423 Page 2 of 2 Commitments made in this letter: None
Attachment:
- 1. Supplement to License Amendment Request for Changes to Technical Specification 3/4.7.5, "Ultimate Heat Sink."
cc:
U.S. Nuclear Regulatory Commission Region I 2100 Renaissance Blvd Suite 100 King of Prussia, PA 19406-2713 Mohan C. Thadani Project Manager U.S. Nuclear Regulatory Commission One White Flint North, Mail Stop 08 B 1 11555 Rockville Pike Rockville, MD 20852-2738 NRC Senior Resident Inspector Millstone Power Station Director, Radiation Division Department of Energy and Environmental Protection 79 Elm Street Hartford, CT 06106-5127
Serial No 14-172 Docket No. 50-423 Attachment Supplement to License Amendment Request for Changes to Technical Specification 3/4.7.5, "Ultimate Heat Sink" Dominion Nuclear Connecticut, Inc.
Millstone Power Station Unit 3
Serial No 14-172 Docket No. 50-423 Attachment, Page 1 of 2 Supplement to License Amendment Request for Changes to Technical Specifications 3/4.7.5, "Ultimate Heat Sink" By letter dated May 3, 2013, Dominion Nuclear Connecticut, Inc. (DNC) submitted a license amendment request (LAR) for Millstone Power Station Unit 3 (MPS3).
The proposed amendment would modify Technical Specification (TS) 3/4.7.5, "Ultimate Heat Sink," to increase the current ultimate heat sink (UHS) water temperature limit from 750F to 80°F and change the TS Action to state, "With the ultimate heat sink water temperature greater than 80 0F, be in HOT STANDBY within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />." DNC requested approval of the LAR by May 5, 2014 with implementation within 60 days of issuance. A supplement to the LAR was provided to the NRC in a letter dated July 2, 2013. Additionally, DNC responded to two requests for additional information in letters dated October 2, 2013 and January 15, 2014.
Recent DNC review of a vendors' calculation which was done in support of the UHS LAR identified a non-conservative error in the calculation involving the service water to control building chilled water cross tie. This error specifically impacts the discussion provided in, Section 5.3.2.3, "Building Air Conditioning Water Chillers (3HVK*CHL 1 A/B)," of the LAR submittal dated May 3, 2013.
The following is an updated discussion of this section with the additional information highlighted in bold font style:
5.3.2.3 Control Building Air Conditioning Water Chillers (3HVK*CHL I A/B)
FSAR Sections 9.2.1.2 and 9.4.1 describe the Control Building A/C (HVK) water chillers. The SW System provides cooling water to the Control Building chillers and can also be supplied directly as a backup to the Control Building chilled water system.
Calculations were performed to determine the minimum SW flow rate required to remove maximum calculated heat loadings for established design conditions and associated heat loads using SW inlet temperatures up to and including 800F.
Revisions to the required flow analyses for the HVK chillers have credited availability of the HVK booster pumps for some fire scenarios. The HVK booster pumps will be added to the list of equipment credited for Fire Protection / Branch Technical (BTP) 9.5-1 Compliance Report and the program will be revised accordingly.
Analyses have also been performed to demonstrate that the available SW flow will maintain the following acceptable temperatures in the cooled rooms of the Control Building when SW is supplying cooling to the HVK chillers:
Control Room temperature is maintained at a maximum temperature of 950F Computer Room, Instrument Rack Rooms, and Switchgear Rooms are maintained at a maximum temperature of 104'F
Serial No 14-172 Docket No. 50-423 Attachment, Page 2 of 2 SW system minimum available flow analyses described in section 5.2 above have demonstrated delivered flow to the HVK chillers in excess of the minimum required flow at UHS temperatures up to 80'F; therefore, the HVK chillers have acceptable performance considering an increase in UHS temperature from 75 0F to 800F.
As stated above, the service water system can directly supply the Control Building chill water system. When SW is used to directly supply the Control Building chill water system, calculations demonstrate that the room temperature limits (described above) will be met with the exception of the Control Room under a certain set of circumstances. Specifically, the Control Room equilibrium room temperature can reach 960F in the following scenario:
- 1. Both trains of safety related Control Building Air Conditioning Water Chillers (3HVK*CHL I A/B) are nonfunctional (note that if a chiller is nonfunctional, but the crosstie is functional, this configuration is controlled by Technical Requirement 3.7.7.1 of the MPS3 technical requirements manual and is permitted only for a maximum of 30 days), and
- 3. A Loss of Coolant Accident (LOCA) occurs.
This scenario will not occur if either train of Control Building Air Conditioning Water Chillers (3HVK*CHL I A/B) is in operation since one train alone is capable of fulfilling the cooling function. Also, given the tidal nature of the Long Island Sound, the UHS temperature will exceed the allowed peak value of 80°F proposed in the LAR well before an average temperature of 80°F (i.e., a constant 80 0F) is reached as assumed in the calculation. Additionally, in scenarios other than a LOCA, Control Room Temperature can be controlled by opening doors to help cool the Control Room. Hence this scenario, although not explicitly modeled, is not realistically expected to occur. Note also that the 95°F limit is for personnel habitability, not equipment operability. NUMARC 87-00, which addresses station blackout, documents the acceptability of temperatures as high as 110°F for personnel habitability for off normal events. As with the other rooms in the Control Building, the equipment operability limit is 104°F.
The maximum SW outlet temperature for limiting conditions (i.e., with the HVK chiller in operation) was also determined using maximum heat loads and minimum SW flow rates. The maximum calculated outlet temperature was evaluated for the impacts on pipe stress and pipe support qualification calculations for the SW piping downstream of the HVK chiller condensers.
The evaluation demonstrated that the piping and supports will continue to comply with governing design and code requirements as described in Section 5.4.