ML080770171

Request for Additional Information Regarding Proposed License Amendment Request for a One-Time Five-Year Extension of the Type a Test Interval

ML080770171
Person / Time
Site:	North Anna
Issue date:	03/24/2008
From:	Richard Jervey NRC/NRR/ADRO/DORL/LPLII-1
To:	Christian D Virginia Electric & Power Co (VEPCO)
Jervey, Richard 301-415-2728
References
TAC MD7478
Download: ML080770171 (6)

Text

March 24, 2008 Mr. David A. Christian President and Chief Nuclear Officer Virginia Electric and Power Company Innsbrook Technical Center 5000 Dominion Boulevard Glen Allen, VA 23060-6711

SUBJECT:

NORTH ANNA POWER STATION, UNIT NO. 2, REQUEST FOR ADDITIONAL INFORMATION (RAI) REGARDING PROPOSED LICENSE AMENDMENT REQUEST FOR A ONE-TIME 5-YEAR EXTENSION OF THE TYPE A TEST INTERVAL (MD7478)

Dear Mr. Christian:

By letter dated December 5, 2007 (ML073400457), Virginia Electric and Power Company, (Dominion) submitted an amendment request, in the form of a change to the technical specifications to Facility Operating License Number NPF-7 for North Anna Power Station, Unit No. 2. The proposed change will permit a one-time 5-year extension to the 10-year frequency of the performance based leakage rate testing program for Type A tests as required by Regulatory Guide (RG) 1.163. The one-time extension will allow the next Type A test to be performed no later than October 9, 2014.

The NRC staff has reviewed the application and has determined that additional information is required in order to complete their evaluation of the information provided. The NRC staffs request is enclosed.

You are asked to provide a response to the RAI within 30 days.

Sincerely,

/RA/

R. A. Jervey, Project Manager Plant Licensing Branch II-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-339

Enclosure:

RAI cc w/encl: See next page

ML080770171

• transmitted by memo dated OFFICE NRR/LPL2-1/PM NRR/LPD2-1/LA NRR/DRA/APLA/BC NRR/DE/EMCB/BC NRR/LPL2-1/BC NAME RJervey MOBrien MRubin KManoly MWong DATE 03/20/08 03/24/08 12/28/07*

03/11/08*

03/24/08

North Anna Power Station, Units 1 & 2 cc:

Mr. David A. Christian President and Chief Nuclear Officer Virginia Electric and Power Company Innsbrooks Technical Center 5000 Dominion Boulevard Glen Allen, VA 23060-6711 Mr. C. Lee Lintecum County Administrator Louisa County Post Office Box 160 Louisa, Virginia 23093 Ms. Lillian M. Cuoco, Esq.

Senior Counsel Dominion Resources Services, Inc.

120 Tredegar Street, RS-2 Richmond, VA 23219 Dr. W. T. Lough Virginia State Corporation Commission Division of Energy Regulation Post Office Box 1197 Richmond, Virginia 23218 Old Dominion Electric Cooperative 4201 Dominion Blvd.

Glen Allen, Virginia 23060 Mr. Chris L. Funderburk, Director Nuclear Licensing & Operations Support Dominion Resources Services, Inc.

Innsbrook Technical Center 5000 Dominion Blvd.

Glen Allen, Virginia 23060-6711 Office of the Attorney General Commonwealth of Virginia 900 East Main Street Richmond, Virginia 23219 Senior Resident Inspector North Anna Power Station U. S. Nuclear Regulatory Commission P. O. Box 490 Mineral, Virginia 23117 Mr. Daniel G. Stoddard Site Vice President North Anna Power Station Virginia Electric and Power Company Post Office Box 402 Mineral, Virginia 23117-0402 Dr. Robert B. Stroube, MD, MPH State Health Commissioner Office of the Commissioner Virginia Department of Health Post Office Box 2448 Richmond, Virginia 23218 Mr. Mark D. Sartain, Director Nuclear Safety & Licensing Virginia Electric and Power Company North Anna Power Station P.O. Box 402 Mineral, VA 23117

Enclosure REQUEST FOR ADDITIONAL INFORMATION PROPOSED ONE-TIME 5-YEAR EXTENSION OF THE TYPE A TEST INTERVAL NORTH ANNA POWER STATION, UNIT NO 2 (NORTH ANNA 2)

DOCKET NO. 50-339 Probabilistic Risk Assessment Questions:

1.

Table 3 of Attachment 2 of the licensees letter dated December 5, 2007, (Agencywide Documents Access and Management System Accession Number ML073400457) provides the estimated population dose for each accident class as well as the total population dose summed over all accident classes. The total population dose in Table 3 (37.31 person-rem per year) is substantially higher than the value reported in the Severe Accident Mitigation Alternative (SAMA) analysis submitted in support of North Anna 2 license renewal (25.4 person-rem per year). The difference appears to be due to a higher population dose value for Class 2 events in Table 3 (1.85E+06 person-rem per event) relative to the frequency-weighted sum of the population dose values for Class 2 events in Table A-1 (1.18E+04 person-rem per event). Use of the higher dose values leads to an under-estimate of the percent increase in the population dose resulting from the integrated leak rate test (ILRT) interval extension. Please reconcile the population dose values with those in the SAMA analysis, and provide a reassessment of the impact of the ILRT interval extension on population dose based on appropriate population dose values.

2.

The total large early release frequency (LERF) for North Anna 2, including the requested change, is stated to be 1.04E-6 per year (page 20 of Attachment 2 to the December 5, 2007 request.) However, this value does not include the contribution to LERF from external events. As stated in Section 2.2.4 of Regulatory Guide (RG) 1.174, the risk-acceptance guidelines (in this case, for LERF) are intended for comparison with a full-scope assessment risk assessment, including internal and external events. Consistent with this guidance, and to the extent supportable by the available risk models for North Anna 2, provide an estimate of the total LERF when external events and the impact of the requested change are included within the assessment.

Other Review Questions:

1.

Please provide a summary list of those containment penetrations (including their test schedule intervals) that have not demonstrated acceptable performance history in accordance with the primary containment leakage rate program.

2.

Please provide a summary table for Type B and Type C tests (including the interval schedule dates) that are planned to be performed prior to and during the requested 5-year extension period of the ILRT interval.

3.

Regulatory Position C.3 of RG 1.163 recommends that visual examinations should be conducted prior to initiating a Type A test, and during two other refueling outages before the next Type A test based on a 10-year ILRT interval. Please describe, with a schedule, how you would supplement this 10-year interval-based visual inspection requirement for the requested 15-year ILRT interval.

4.

Please provide information relative to the findings (if any) and actions taken where existence of or potential for degraded conditions in inaccessible areas of the containment structure and metallic liner were evaluated based on conditions found in accessible areas as required by 10 CFR 50.55a(b)(2)(viii)(E) and 10 CFR 50.55a(b)(2)(ix)(A).

5.

In Section 4.6 of Attachment 1 to the TS amendment request, it is stated that, in the first 10-year interval of the American Society Mechanical Engineers (ASME) Code, Subsection IWE examinations, the areas associated with the liner damage caused by wood left in the concrete at construction have been ultrasonically examined (Augmented Category E-C Examination). Please provide a summary of areas other than where liner damage was caused due to wood left in the concrete that have been identified for augmented examination (if any).

It is also stated that no augmented Category E-C examinations of the areas associated with the liner damage caused by wood left in the concrete are planned for the second 10-year interval IWE examinations since several examinations have shown no change in liner thickness. In light of the proposed TS Amendment to allow a 5-year extension of the Type A test interval, please provide specific information to justify discontinuing the augmented examination of suspect liner area(s) during the second 10-year IWE interval.

6.

Please provide a summary of any degradation identified during past inspections of the containment moisture barrier (e.g., between liner and concrete floor). If any, please describe the condition, corrective actions, and additional monitoring program.

7.

Relative to the results of 1999 ILRT included in Section 4.2 of Attachment 1 to the TS amendment request, there appears to be a typographical error in the total value of as-found leakage. Please review and discuss. Also, provide the actual as-left leakage for the last three Type A tests.

8.

As summarized in Section 4.2 of Attachment 1 to the TS amendment request, the 1999 ILRT as-found leakage was more than twice the value of the 1990 ILRT results.

Please provide further information relative to the potential root cause for this increase.

Also, provide the Type B and Type C test results and their comparison with the allowable leakage rate specified in the plant TSs.

9.

In Section 4.6 of Attachment 1 to the TS amendment request, it is stated that in the second 5-year IWL examination of the North Anna 2 containment structure (completed in August of 2007) several pieces of embedded material were identified. Please discuss the type and the extent of concrete repair, and if there was any liner damage associated with this condition. Furthermore, please discuss if there has been a complete direct inspection of the North Anna 2 containment structure.

10.

If bellows are used on penetrations through containment pressure-retaining boundaries at North Anna 2, please provide information on their location, inspection, testing and operating experience with regard to detection of leakage through the penetration bellows.

11.

Please provide an overview of the containment liner coating inspection program at North Anna 2 including inspection intervals, findings and corrective actions identified during recent inspections.

12.

In Section 4.6 of Attachment 1 to the TS amendment request, the following is stated:

The second ten-year interval IWE program for North Anna meets the requirements of the 2001 Edition through the 2003 Addenda of ASME Section XI. Categories E-D and E-G are no longer part of the code. The relief requests above are not needed for the second 10-year interval since examination of seals and gaskets, and bolt torque or tension tests are no longer addressed by ASME Section XI. As such, the extension request will no longer impact the ASME Section XI program upon second interval start for each unit. Given the short time period remaining in the first 10-year IWE lSI interval for the North Anna units, and the Type B and C tests performed during the first 10-year IWE lSI interval, the Appendix J, Type A extension is seen as having a negligible impact.

Please provide clarification for the following:

a.

The TS Amendment request submitted in Dominion letter dated December 5, 2007, is for North Anna 2. It is not clear to the NRC staff why both units are being discussed in the above paragraph.

b.

Please discuss the examination method(s) in North Anna 2 to ensure leak-tight integrity of those penetrations with seals and gaskets, and bolted connections.

c.

Please clarify the last sentence of the subject paragraph (Given the short time period remaining ).