ML082130424

Request for Additional Information, Allowable Value for Containment Purge Exhaust Radiation Monitors

ML082130424
Person / Time
Site:	Watts Bar
Issue date:	08/01/2008
From:	Milano P NRC/NRR/ADRO/DORL/WBSPB
To:	Campbell W Tennessee Valley Authority
Milano P, NRR/DORL , 415-1457
References
TAC MD8395
Download: ML082130424 (7)

Text

August 1, 2008 Mr. William R. Campbell, Jr.

Chief Nuclear Officer and Executive Vice President Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801

SUBJECT:

WATTS BAR NUCLEAR PLANT, UNIT 1 - REQUEST FOR ADDITIONAL INFORMATION REGARDING ALLOWABLE VALUE FOR CONTAINMENT PURGE EXHAUST RADIATION MONITORS (TAC NO. MD8395)

Dear Mr. Campbell:

By application dated March 27, 2008, Tennessee Valley Authority (TVA) proposed a license amendment to change Watts Bar Nuclear Plant, Unit 1, Technical Specifications. The proposed change would revise the allowable value listed for Function 3, Containment Purge Exhaust Radiation Monitors, in Table 3.3.6-1, Containment Vent Isolation Instrumentation, of LCO 3.3.6.

The containment purge exhaust radiation monitors initiate containment vent isolation to mitigate the potential release of radioactive effluents via this flow path following a postulated small break loss-of-coolant accident.

The staff has reviewed the information provided by TVA and has determined that additional information is required to complete its evaluation of the proposed license amendment. The specific questions are detailed in the enclosed request for additional information (RAI). Based on discussions with your staff, we understand that you plan to respond to the enclosed RAI within 45 days of the date of this letter.

If you have any questions regarding this issue, please feel free to contact me at (301) 415-1457.

Sincerely,

/RA/

Patrick D. Milano, Senior Project Manager Watts Bar Special Projects Branch Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-390

Enclosure:

RAI cc w/enclosure: See next page

Mr. William R. Campbell, Jr.

Chief Nuclear Officer and Executive Vice President Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801

SUBJECT:

WATTS BAR NUCLEAR PLANT, UNIT 1 - REQUEST FOR ADDITIONAL INFORMATION REGARDING ALLOWABLE VALUE FOR CONTAINMENT PURGE EXHAUST RADIATION MONITORS (TAC NO. MD8395)

Dear Mr. Campbell:

By application dated March 27, 2008, Tennessee Valley Authority (TVA) proposed a license amendment to change Watts Bar Nuclear Plant, Unit 1, Technical Specifications. The proposed change would revise the allowable value listed for Function 3, Containment Purge Exhaust Radiation Monitors, in Table 3.3.6-1, Containment Vent Isolation Instrumentation, of LCO 3.3.6.

The containment purge exhaust radiation monitors initiate containment vent isolation to mitigate the potential release of radioactive effluents via this flow path following a postulated small break loss-of-coolant accident.

The staff has reviewed the information provided by TVA and has determined that additional information is required to complete its evaluation of the proposed license amendment. The specific questions are detailed in the enclosed request for additional information (RAI). Based on discussions with your staff, we understand that you plan to respond to the enclosed RAI within 45 days of the date of this letter.

If you have any questions regarding this issue, please feel free to contact me at (301) 415-1457.

Sincerely,

/RA/

Patrick D. Milano, Senior Project Manager Watts Bar Special Projects Branch Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-390

Enclosure:

RAI cc w/enclosures: See next page DISTRIBUTION:

PUBLIC RidsNrrPMPMilano H. Garg, NRR RidsAcrsAcnwMailCenter LP-WB R/F RidsNrrLABClayton RidsOgcRp RidsNrrDorlDpr RidsNrrDorlLpwb RidsNrrDeEicb RidRgn2MailCenter ADAMS Accession Number: ML082130424 OFFICE WBSPB/PM WBSPB/LA EICB/BC WBSPB/BC NAME PMilano BClayton WKemper(by memo dated) LRaghavan DATE 08/ 01 /08 07/31/08 07/09/08 08/ 01 /08 OFFICIAL RECORD COPY

William R. Campbell, Jr.

Tennessee Valley Authority WATTS BAR NUCLEAR PLANT cc:

Mr. Gordon P. Arent Mr. Michael A. Purcell New Generation Licensing Manager Senior Licensing Manager Tennessee Valley Authority Nuclear Power Group 5A Lookout Place Tennessee Valley Authority 1101 Market Street 4K Lookout Place Chattanooga, TN 37402-2801 1101 Market Street Chattanooga, TN 37402-2801 Mr. Ashok S. Bhatnagar Senior Vice President Ms. Beth A. Wetzel, Manager Nuclear Generation Development Corporate Nuclear Licensing and and Construction Industry Affairs Tennessee Valley Authority Tennessee Valley Authority 6A Lookout Place 4K Lookout Place 1101 Market Street 1101 Market Street Chattanooga, TN 37402-2801 Chattanooga, TN 37402-2801 Vice President Mr. Masoud Bajestani, Vice President Nuclear Support Watts Bar Unit 2 Tennessee Valley Authority Watts Bar Nuclear Plant 3R Lookout Place Tennessee Valley Authority 1101 Market Street P.O. Box 2000 Chattanooga, TN 37402-2801 Spring City, TN 37381 Mr. Michael J. Lorek Mr. Michael K. Brandon, Manager Vice President Licensing and Industry Affairs Nuclear Engineering & Technical Services Watts Bar Nuclear Plant Tennessee Valley Authority Tennessee Valley Authority 3R Lookout Place P.O. Box 2000 1101 Market Street Spring City, TN 37381 Chattanooga, TN 37402-2801 Mr. Gregory A. Boerschig, Plant Manager General Counsel Watts Bar Nuclear Plant Tennessee Valley Authority Tennessee Valley Authority 6A West Tower P.O. Box 2000 400 West Summit Hill Drive Spring City, TN 37381 Knoxville, TN 37902 Senior Resident Inspector Mr. John C. Fornicola, Manager Watts Bar Nuclear Plant Nuclear Assurance U.S. Nuclear Regulatory Commission Tennessee Valley Authority 1260 Nuclear Plant Road 3R Lookout Place Spring City, TN 37381 1101 Market Street Chattanooga, TN 37402-2801 County Executive 375 Church Street Mr. Larry E. Nicholson, General Manager Suite 215 Performance Improvement Dayton, TN 37321 Tennessee Valley Authority 3R Lookout Place County Mayor 1101 Market Street P. O. Box 156 Chattanooga, TN 37402-2801 Decatur, TN 37322 Mr. Michael D. Skaggs Mr. Lawrence E. Nanney, Director Site Vice President Division of Radiological Health Watts Bar Nuclear Plant Dept. of Environment & Conservation Tennessee Valley Authority Third Floor, L and C Annex P. O. Box 2000 401 Church Street Spring City, TN 37381 Nashville, TN 37243-1532

Request for Additional Information Allowable Value for Containment Purge Exhaust Radiation Monitors Watts Bar Nuclear Plant, Unit 1 Tennessee Valley Authority Docket No. 50-390 By letter dated March 27, 2008 (Agencywide Documents Access and Management System Accession No. ML080870349), Tennessee Valley Authority (TVA) proposed a change to the Watts Bar Nuclear Plant Unit 1 (WBN 1) Technical Specifications (TSs). The proposed change would revise the allowable value (AV) listed for Function 3, Containment Purge Exhaust Radiation Monitors, in Table 3.3.6-1, Containment Vent Isolation Instrumentation.

After reviewing the information provided by TVA, the NRC staff requests the following information:

1. On page E1-3 of the Enclosure to the application, TVA states:

Because the monitors are not used to protect the reactor fuel or the Reactor Coolant System (RCS) safety barriers, the AV specified in the TS for this device is not a 10 CFR 50.36 limiting safety system setting.

The Nuclear Regulatory Commission staff does not agree with this statement, in that Title 10 of the Code of Federal Regulations (10 CFR) Section 50.36(d)(1)(ii)(A) states that Limiting safety system settings for nuclear reactors are settings for automatic protective devices related to those variables having significant safety functions. The instrumentation required by the TSs has been designed to assure that the applicable safety analysis limits will not be exceeded during anticipated operational occurrences and the settings must initiate automatic protective actions consistent with the design basis. Since the function of the containment purge exhaust radiation monitors is used to limit the radiological consequences of a design-basis small-break loss-of-coolant accident to within the limits of 10 CFR Part 100, Reactor Site Criteria, they perform a significant safety function.

However, the NRC staff agrees that this function is not used to protect the reactor fuel or the RCS safety barriers, and therefore, does not have a safety limit limiting safety system setting (SL-LSSS).

TVA should revise its statement.

2. Provide a discussion, including the calculation, of the setpoint calculation methodology used for establishing the limiting trip setpoint (or the nominal trip setpoint) and the instrument setting tolerance (a range of values around the limiting trip setpoint) for the as-found and as-left setpoints as measured in periodic surveillance testing. Indicate the analytical limits and other limiting design values (and the sources of these values) for the limiting trip setpoint and setting tolerance range, including expected uncertainties in the instrument setpoint determination.

Enclosure

3. Since this setpoint has been determined not to be SL-LSSS, describe the measures to be taken to ensure that the associated instrument channel is capable of performing its specified safety functions in accordance with applicable design requirements and associated analyses. Include information on the controls TVA will employ to ensure that the as-left trip setting (after completion of periodic surveillance) is consistent with the setpoint methodology and calculation. Also, discuss the plant corrective action processes (including plant procedures) for restoring channels to operable status when channels are determined to be inoperable or operable but degraded. If the controls are located in a document other than the TSs (e.g., plant test procedure), describe how implementation of the controls is ensured.