ML14154A091

Response to Request for Additional Information Regarding License Amendment Request for Changes to Technical Specification 3/4.7.5, Ultimate Heat Sink.

ML14154A091
Person / Time
Site:	Millstone
Issue date:	05/28/2014
From:	Stoddard D Dominion, Dominion Nuclear Connecticut
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
14-271
Download: ML14154A091 (8)

Text

Dominion Nuclear Connecticut, Inc.

5000 Dominion Boulevard, Glen Allen, VA 23060 SDominion Web Address: www.dom.com May 28, 2014 U. S. Nuclear Regulatory Commission Serial No.14-271 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 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING 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 80'F, 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 />."

In a letter dated June 26, 2013, the Nuclear Regulatory Commission (NRC) provided DNC an opportunity to supplement the LAR identified above. Supplemental information was provided to the NRC in a letter dated July 2, 2013. In an e-mail dated September 5, 2013, the NRC transmitted a request for additional information (RAI) related to the LAR. DNC responded to the RAI in a letter dated October 2, 2013. In a letter dated December 19, 2013, the NRC transmitted a second RAI. DNC responded to the RAI in a letter dated January 15, 2014. In a letter dated April 23, 2014, DNC provided supplemental information to Section 5.3.2.3 of Attachment 1 of the LAR submittal of May 3, 2013. In an e-mail dated May 19, 2014, the NRC transmitted a third RAI. to this letter contains DNC's response to the third RAI.

If you have any questions or require additional information, please contact Wanda Craft at (804) 273-4687.

Sincerely,

- I, m

VICKI L. HULL Daniel G. Stoddard Notary Public Commonwealth of Virginia Senior Vice President - Nuclear Operations 140542 My Commission Expires Mayv31, v2014 v a v

. . . n COMMONWEALTH OF VIRGINIA )

)

COUNTY OF HENRICO The foregoing document was acknowledged before me, in and for the County and Commonwealth aforesaid, today by Daniel G.

Stoddard, who is Senior Vice President - Nuclear Operations 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 0 - day of( /A_ , 2014.

My Commission Expires: 5 -- 3/ /4. " A(

Notary Publlic

Serial No.14-271 Docket No. 50-423 Page 2 of 2 Commitments made in this letter: None

Attachment:

1. Response to Request for Additional Information Regarding License Amendment Request for Changes to Technical Specifications 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 Thadani Senior Project Manager U.S. Nuclear Regulatory Commission One White Flint North, Mail Stop 08 B1 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 14-271 Docket No. 50-423 Attachment 1 Response to Request for Additional Information Regarding License Amendment Request for Changes to Technical Specifications 3/4.7.5, "Ultimate Heat Sink" Dominion Nuclear Connecticut, Inc.

Millstone Power Station Unit 3

Serial No 14-271 Docket No. 50-423 Attachment 1, Page 1 of 3 Response to Request for Additional Information Regarding 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 75"F to 80OF and change the TS Action to state, "With the ultimate heat sink water temperature greater than 80'F, 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 />."

In a letter dated June 26, 2013, the Nuclear Regulatory Commission (NRC) provided DNC an opportunity to supplement the LAR identified above. Supplemental information was provided to the NRC in a letter dated July 2, 2013. In an e-mail dated September 5, 2013, the NRC transmitted a request for additional information (RAI) related to the LAR. DNC responded to the RAI in a letter dated October 2, 2013. In a letter dated December 19, 2013, the NRC transmitted a second RAI. DNC responded to the RAI in a letter dated January 15, 2014. In a letter dated April 23, 2014, DNC provided supplemental information to Section 5.3.2.3 of of the LAR submittal of May 3, 2013. In an email dated May 19, 2014, the NRC transmitted a third RAI. The response to this RAI is provided below.

RAI-1

The license amendment request (LAR) of May 3, 2013 requests a change to Surveillance Requirement (SR) 4.7.5, which does not now include the most current revision of SR 4.7.5.

The licensee is requested to provide the proposed change to SR 4.7.5 using the current revision.

DNC Response MPS3 Amendment 258, approved February 25, 2014, impacted Technical Specification page 3/4 7-13. The most current revision of page 3/4 7-13 is provided in Enclosure 1 of this attachment and is marked-up to indicate the proposed changes discussed in the license amendment request of May 3, 2013.

RAI-2

In the LAR for LCO 3.7.5 and SR 4.7.5, the licensee changed the parameterto be monitored from "averagewater temperature"to "watertemperature."

The licensee is requested to explain the technical reasons andjustify changing the parameter to be monitored as explained above.

Serial No 14-271 Docket No. 50-423 Attachment 1, Page 2 of 3 DNC Response At the time the LAR was submitted, the service water system had no remote temperature monitoring instrumentation available. However, the non-safety related circulating water system has remote temperature monitoring instrumentation in each circulating water inlet water box (six total). Since the circulating water pumps take water from the UHS near the suction of the service water pumps, the temperature recorded at the circulating water inlet water box was considered representative of service water inlet temperature. However, these instruments did not have a documented uncertainty. To obtain a higher confidence in the indication of UHS temperature, the in-service water box temperatures were averaged to determine UHS temperature. This was described in the existing bases of the Technical Specification as included in the original LAR submittal of May 3, 2013. However, as a result of the Millstone Unit 2 shutdown due to high UHS temperature in August 2012, the use of these instruments was reconsidered. Detailed measurements showed that the use of the circulating water inlet waterbox temperatures could be non-conservative by approximately 10 F. Therefore, as described in the May 3, 2013 LAR, remote indicating precision temperature monitoring instrumentation was installed at MPS3 at each train's service water inlet to the reactor plant closed cooling water (RPCCW) heat exchangers and the in-service instruments must be within the UHS temperature limit. This instrumentation provides more representative and precise indication of UHS temperature and is used to monitor compliance with the UHS Technical Specification in SR 4.7.5.

RAI-3

In the licensee's letter, dated January 15, 2014, as a response to request for additional information (RAI) 4, regardingthe ESF air conditioning unit (3HVQ ACUSIA, 1B, 2A, and 2B) condensers, the licensee explained the seemingly low service water flow rate of 25 gpm and 33.2 gpm by allowing the service water (SW) AT across the heat exchangers to increase to transfer the heat for condensing the R-22 Freon. With a SW inlet temperature of 80°F, the vendor data sheet has a AT of 15.7 0F, while the licensee's calculated AT's are 29.5°F and 24.4 0F. The licensee justified the seemingly low SW flow rate by allowing higher SW ATs.

The licensee did not address the effect of the corresponding higher SW temperatures across the condensers on the condensing effects of the R-22, but called the results "reasonable."

Provide definitive statements, as appropriate, regarding the operability of the ESF air conditioning units to perform their safety functions and remove design heat loads under accident conditions with an 80°F SW inlet temperature and the high SW ATs and low flow rates described in your RAI response. Describe any adverse effect on the R-22 condensing function with the higher SW AT and the ability of the ESF units to perform their safety functions.

DNC Response The acceptability of 80OF service water to the ESF air conditioning unit condensers (HVQ chillers) was evaluated in calculation 97-002, Rev 3, Addendum B. The HVQ chillers are

Serial No 14-271 Docket No. 50-423 Attachment 1, Page 3 of 3 Freon to water heat exchangers. When the service water side average temperature increases, the Freon side average temperature also increases to obtain the required heat removal rate. The following excerpts from this calculation address the concerns of the question:

• The refrigerant for the 3HVQ*ACUS1A, 3HVQ*ACUS2A, 3HVQ*ACUS1B, and 3HVQ*ACUS2B condensers is R-22 and the compressor Normal Operating Range Limit is 255 psig (269.7 psia).

" The condenser pressure vs. temperature relationship is defined by the saturated properties of R-22 for condensers 3HVQ*ACUS1A, 3HVQ*ACUS2A, 3HVQ*ACUS1B, and 3HVQ*ACUS2B.

" The highest calculated refrigerant temperature (based on 24.97 gpm of 80'F service water) for 3HVQ*ACUS1A and 3HVQ*ACUS1B is 116.98 OF. The refrigerant is R-22, at a saturated pressure of 264.3 psia, which is less than the 269.7 psia allowable pressure. Therefore, the condensing pressure of 3HVQ*ACUS1A and 3HVQ*ACUS1B is acceptable.

• The highest calculated refrigerant temperature (based on 33.15 gpm of 80°F service water) for 3HVQ*ACUS2A and 3HVQ*ACUS2B is 112.29 OF. The refrigerant is R-22, at a saturated pressure of 248.6 psia, which is less than the 269.7 psia allowable pressure. Therefore, the condensing pressure of 3HVQ*ACUS2A and 3HVQ*ACUS2B is acceptable.

Therefore, it is concluded that these chillers are fully capable of removing the required heat load at 80°F service water temperature assuming the worst case calculated flow rates.

Serial No 14-271 Docket No. 50-423 Enclosure 1 Marked-Up Technical Specifications Page Dominion Nuclear Connecticut, Inc.

Millstone Power Station Unit 3

Serial No 14-271 Docket No. 50-423 PLANT SYSTEMS 3/4.7.5 ULTIMATE HEAT SINK LIMITING CONDITION FOR OPERATION 3.7.5 The ultimate heat sink (UHS) shall be OPERABLE with afu aierwage water temperature nf 1ev thnn nhr Onllnd tn SS. rr-l-With the UHS water temperature greater MODES 1, 2, 3, and 4. than 80 0 F, be in HOT STANDBY within 6 APPLICABILITY: I' hours and in COLD SHUTDOWN within the ACTION:

following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.

Iftho UHF tz:pzraturz do no.t drop below ;94 dur-ing thin p.iod..la*z,.... the ii.i;at LHOT STAoNDBY4 within the nz:4 6 heura and ini C-OLD SHUTDOWN withinl toe followitg 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />. Duiring ti ..... ,..if... .UH t...ratur

. ........ t.. o. 7:7R, plan th. plf.. in HO(T-ST10iDBY4 wAkithi 41h0 neif 6 hour- and 4in COLD SHUT:DOWZN withini the foqllowing 30-haere SURVEILLANCE REQUIREMENTS 4.7.5 The UHS shall be determined OPERABLE:

a. At the frequency specified in the Surveillance Frequency Control Program by 4-I verifying the e,-enge water temperature to be within limits.

b. At least once per 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> by verifying the twei'ge water temperature to be within lim its when the aereage water temperature exceeds -7.F MILLSTONE - UNIT.3 3/4 7-13 MIAmendment No. 449, m8 k-I