ML112430084

Request for Additional Information Regarding License Amendment Request to Revise Technical Specification 3.7.4,Atmospheric Dump Valves

ML112430084
Person / Time
Site:	Palo Verde
Issue date:	08/31/2011
From:	Lauren Gibson Plant Licensing Branch IV
To:	Edington R Arizona Public Service Co
Gibson, Lauren, NRR/DORL/LPL4, 415-1056
References
TAC ME6566, TAC ME6567, TAC ME6568
Download: ML112430084 (4)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555*0001 August 31, 2011 Mr. Randall K. Edington Executive Vice President Nuclearl Chief Nuclear Officer Ma iI Station 7602 Arizona Public Service Company P.O. Box 52034 Phoenix, AZ 85072-2034

SUBJECT:

PALO VERDE NUCLEAR GENERATING STATION, UNITS 1, 2, AND 3 REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST TO REVISE TECHNICAL SPECIFICATION 3.7.4, "ATMOSPHERIC DUMP VALVES" (TAC NOS. ME6566, ME6567, AND ME6568)

Dear Mr. Edington:

By letter dated June 22,2011 (Agencywide Documents Access and Management System Accession No. ML11182A908), Arizona Public Service Company, the licensee for Palo Verde Nuclear Generating Station Units 1, 2, and 3, requested a license amendment that would revise Technical Specification Limiting Condition for Operation 3.7.4, "Atmospheric Dump Valves (ADVs)." The proposed change would require four ADV lines to be operable in MODES 1, 2, and 3, as well as MODE 4 when a steam generator is relied upon for heat removal.

The U.S. Nuclear Regulatory Commission (NRC) staff has reviewed the information provided by the licensee and determined that the additional information identified in the enclosure to this letter is needed in order for the NRC staff to complete its review. The draft copy of the request for additional information was provided to Mr. Russell Stroud of your staff via e-mail on Friday, August 26, 2011. A conference call to clarify the requests for additional information was held with Mr. Tom Weber and other members of your staff on August 31,2011. During that call, Mr.

Weber agreed to provide a response to the requests for additional information by December 9, 2011.

R.Edington -2 If you have any questions, please contact me at (301) 415-1056 or via e-mail at Lauren. Gibson@nrc.gov.

Sincerely, Lauren K. Gibson, Project Manager Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. STN 50-528, STN 50-529, and STN 50-530

Enclosure:

As stated cc w/encl: Distribution via Listserv

REQUEST FOR ADDITIONAL INFORMATION PALO VERDE NUCLEAR GENERATING STATION LICENSE AMENDMENT REQUEST CONCERNING TECHNICAL SPECIFICATION 3.7.4 ATMOSPHERIC DUMP VALVES T AC NOS. ME6566. ME6567! ME6568 By letter dated June 22, 2011, Arizona Public Service Company, the licensee for Palo Verde Nuclear Generating Station Units 1, 2, and 3, requested a license amendment that would revise Technical Specification Limiting Condition for Operation (LCO) 3.7.4, Atmospheric Dump Valves (ADVs).

In order to cornplete the review, the staff requests the following additional information.

1. Please provide the technical basis, including a discussion of defense in depth and safety margins, for:

a. Proposed LCO 3.7.4, Condition A, Completion Time of 7 days

b. Proposed LCO 3.7.4, Condition B, Completion Time of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

2. Regarding the design-basis events for which ADVs are required, and which require the consideration of loss of offsite power, please explain how the main steam condenser provides defense in depth to the ADV safety and design functions.

3. Discuss the impact that local manual ADV operation or maintaining steam generator pressure with main steam safety valves would have on safety margin for design-basis events, including but not necessarily limited to:

a. Postulated loss-of-coolant accidents

b. Natural circulation cooldown as described in Generic Letter 81-21

c. Steam generator tube rupture events

d. Main steam and feedwater line breaks Enclosure

R.Edington -2 If you have any questions, please contact me at (301) 415-1056 or via e-mail at Lauren.Gibson@nrc.gov.

Sincerely, IRAI Lauren K. Gibson, Project Manager Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. STN 50-528, STN 50-529, and STN 50-530

Enclosure:

As stated cc w/encl: Distribution via Listserv DISTRIBUTION:

PUBLIC RidsNrrDorlLpl4 Resource RidsOgcRp Resource LPLIV rlf RidsNrrPMPaloVerde Resource RidsRgn4MailCenter Resource RidsAcrsAcnw_MaiICTR Resource RidsNrrLAJBurkhardt Resource ADAMS Accession No. ML112430084 *via email OFFICE

• NRR/LPL4/PM NRR/LPL4/LA NRR/LPL4/BC ILPL4/PM JBurkhardt (ABaxter NAME LKGibson MMarkley LKGibson for)*

DATE 8/31/11 08/31/11 8131111 8/31/11