ML15261A565

Request for Additional Information Regarding Proposed Revision of Technical Specifications for Containment Leak Rate Testing

ML15261A565
Person / Time
Site:	Grand Gulf
Issue date:	09/24/2015
From:	Wang A Plant Licensing Branch IV
To:	Entergy Operations
Wang A
References
TAC MF6310
Download: ML15261A565 (7)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 September 24, 2015 Vice President, Operations Entergy Operations, Inc.

Grand Gulf Nuclear Station P.O. Box 756 Port Gibson, MS 39150

SUBJECT:

GRAND GULF NUCLEAR STATION, UNIT 1 - REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST TO REVISE TECHNICAL SPECIFICATIONS FOR CONTAINMENT LEAK RATE TESTING (TAC NO. MF6310)

Dear Sir or Madam:

The U.S. Nuclear Regulatory Commission staff has determined that additional information is needed to complete its review of the subject license amendment request for Grand Gulf Nuclear Station, Unit 1, submitted by Entergy Operations, Inc., dated May 27, 2015 (Agencywide Documents Access and Management System Accession No. ML15147A599). The enclosed questions constitute our request for additional information (RAI).

This RAI was discussed with Mr. Richard Scarbrough on September 17, 2015, and it was agreed that a response would be provided within 30 days of receipt of this letter. If circumstances result in the need to revise the requested response date, please contact Stephen Koenick at 301-415-6631 or Stephen.Koenick@nrc.gov.

Sincerely, W.::x; (,,

Alan B. Wang, Project Manager Plant Licensing IV-2 and Decommissioning Transition Branch Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-416

Enclosure:

Request for Additional Information cc w/enclosure: Distribution via Listserv

REQUEST FOR ADDITIONAL INFORMATION GRAND GULF NUCLEAR STATION. UNIT 1.

LICENSE AMENDMENT REQUEST TO REVISE TECHNICAL SPECIFICATIONS FOR CONTAINMENT LEAK RATE TESTING By application dated May 27, 2015 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML15147A599), Entergy Operations, Inc. (Entergy or the licensee) requested changes to the technical specifications (TSs) for Grand Gulf Nuclear Station, Unit 1 (GGNS). The proposed changes would permit the existing Title 1O of the Code of Federal Regulations (10 CFR) Part 50, Appendix J, "Primary Reactor Containment Leakage Testing for Water-Cooled Power Reactors," Type C Local Leak Rate Test (LLRT) frequency to be extended from 5 years up to 75 months on a permanent basis and a permanent reduction of 10 CFR 50, Appendix J, Type B and Type C test grace intervals.

The U.S. Nuclear Regulatory Commission (NRC) staff has determined that additional information is needed to complete its review of the subject license amendment request (LAR).

The following questions constitute our request for additional information (RAI).

The regulation at 10 CFR Section 50.54(0) requires primary reactor containments for water-cooled power reactors to be subject to the requirements of Appendix J to 10 CFR Part 50, "Leakage Rate Testing of Containment of Water Cooled Nuclear Power Plants." Appendix J specifies containment leakage testing requirements, including the types of tests required to ensure the leak-tight integrity of the primary reactor containment, systems, and components that penetrate the containment. In addition, Appendix J discusses leakage rate acceptance criteria, test methodology, frequency of testing, and reporting requirements for each type of test.

Option B to 10 CFR Part 50, Appendix J, requires that test intervals for Type A, Type B, and Type C testing be determined by using a performance-based approach. Performance-based test intervals are based on consideration of operating history of the component and resulting risk from its failure. Performance-based for Appendix J refers to both the performance history necessary to extend test intervals and the criteria necessary to meet the requirements of Option B.

The NRC staff approved the Nuclear Energy Institute (NEI) 94-01, Revision 3, "Industry Guideline for Implementing Performance-Based Option of 10 CFR Part 50, Appendix J,"

(ADAMS Accession No. ML12221A202) by NRC final safety evaluation report dated June 8, 2012 (ADAMS Accession No. ML121030286). Accordingly, if a licensee considers an extended test interval of greater than 60 months, the review to establish the surveillance test intervals should include programmatic controls to provide additional assurance that the increased probability of component leakage is kept to a minimum.

In Attachment 1 of Entergy's application, "Evaluation of the Proposed Change," Section 3.4.2, "Use of Grace in the Deferral of Type Band Type C Testing," the licensee notes: "For routine scheduling of tests at intervals over 60 months, refer to the additional requirements of Section 11.3.2" (i.e., of NEI 94-01, Revision 3-A (ADAMS Accession No. ML12221A202)).

However, the evaluation does not address how the recommended "additional considerations" (i.e., "as-found tests," "schedule," and "review") of Section 11.3.2 were applied to the Type B and Type C LLRT data contained in LAR Attachment 1, Tables 3.3.1-1 and 3.3.1-2.

The staff requests that Entergy provide the information related to the programmatic controls to support extended Type C LLRT test intervals beyond 60 months.

The staff notes that on July 18, 2012, the NRC approved License Amendment No. 191 (ADAMS Accession No. ML121210020) for GGNS to increase the maximum steady state reactor core power level by approximately 15 percent from the original licensed thermal power level of 3,833 megawatt thermal (i.e., extended power uprate (EPU)). The license was also amended to include a new License Condition 2.C.(44), which states, in part, that leak rate tests associated with surveillance requirements required by TS 5.5.12 are not required to be performed until their next scheduled performance dates.

License Condition 2.C.(44) states that the leak rate tests required in refueling outage RF-18 (i.e., fall of 2012) were to be performed at the EPU calculated peak containment pressure or within the EPU drywell bypass leakage limits, as appropriate. License Amendment No. 191 changed the license basis "Pa" of 11.5 pounds per square inch gauge (psig) to the current license basis (CLB) "Pa" of 14.8 psig, as reflected in the current TS 5.5.12.

The staff requests additional information regarding the LLRT Pa values used to perform Type B and Type C tests contained in LAR Attachment 1, Table 3.3.1-1, "Types Band C LLRT Combined As-Found/As-Left Trend Summary."

1) How many of the 78 component Type B tests and 151 component Type C tests were performed at the CLB Pa value of 14.8 psig during 2012 (RF-18) and 2014 (RF-19)?

2) Were any of the Type B and Type C component tests performed at the CLB Pa value of 14.8 psig before RF-18 (2012)?

3) How many Type B penetration tests and Type C containment isolation valve tests have yet to be performed at the CLB Pa value of 14.8 psig?

4) When was the last 10 CFR 50, Appendix J, Type A, ILRT performed on the containment at GGNS? What was the ILRT leakage (i.e., total of Type A+B+C) rate for this ILRT?

What was the range of the containment internal test pressure, Pa. during this ILRT?

5) The last paragraph of LAR Section 3.3.1, Attachment 1 (page 11 of 26), reads:

Table 3.3.1-1 provides the LLRT data trend summaries for GGNS since 2005 and encompasses previous ILRTs." This would imply that more than one ILRT was performed between the years of 2005 and 2014. If more than one ILRT was performed

during this timeframe, please provide the ILRT leakage rate and the range of the containment internal test pressure, Pa, recorded during the ILRT(s) performed.

The staff notes that an e-mail from Entergy to the NRC dated August 24, 2011 (ADAMS Accession No. ML112370085), predicted an increase in the total Type B + Type C leakage rate of 13. 75 percent (i.e., 0.182 + 0.160), due to the change in the license basis "Pa" of 11.5 psig to the CLB "Pa" of 14.8 psig. Upon review and analysis of the data contained in LAR Attachment 1, Table 3.3.1-1, the staff notes that the aggregate "AF Min Path" Type B +Type C LLRT leakage has gone up by 65 percent since the NRC issued License Amendment No. 191.

{(5918 + 12885 + 18984 + 18057) + 4} + {(24453+21595) + 2} = 1.65 Performing a similar calculation, larger ratios of 2.57 for the "AL Max Path" and 2.43 for the "AL Min Path" are obtained from the data contained in Table 3.3.3-1 of the LAR.

The staff requests that Entergy provide an explanation of these ratios in light of the GGNS prediction.

LAR Attachment 1 (page 17 of 26), Section 3.4.1, "Limitations and Conditions Applicable to NEI 94-01, Revision 3-A," second paragraph of "Response to Condition 2, ISSUE 1," reads, in part:

When the potential leakage understatement adjusted leak rate total for those Type C components being tested on a 75-month extended interval is summed with the non-adjusted total of those Type C components being tested at less than the 75-month interval and the total of the Type B tested components, if the MNPLR is greaterthan the GGNS administrative leakage summation limit of 0.50 La, but less than the regulatory limit of 0.6 La, then an analysis and corrective action plan shall be prepared to restore the leakage summation value to less than the GGNS administrative leakage limit.

This paragraph could be interpreted to mean that a component tested at 70 months would not be adjusted for the understatement adjustment factor of 1.25, which would not be consistent with the intent of NEI 94-01, Revision 3-A. Please clarify the meaning of the cited paragraph.

NEI 94-01, Revision 3-A, Section 11.3.2, reads, in part:

If a licensee considers extended test intervals of greater than 60 months for a Type B or a Type C tested component, the review to establish surveillance test intervals should include the additional considerations:

• As-found Tests - In order to provide additional assurance that the increased probability of component leakage is kept to a minimum, and is reasonably within the envelope of industry data, a licensee should consider requiring three successive periodic as-found tests to determine adequate performance.

LAR Attachment 1 (page 15 of 26), Section 3.3.2, "Type B and Type C Tested Components on Extended Intervals," reads:

The percentage of the total number of GGNS Type B tested components (78) that are on 120 month extended performance-based test interval is 65%.

The percentage of the total number of GGNS Type C tested components (151) that are on 60 month extended performance-based test interval is 58%.

GGNS's May 27, 2015, proposed amendment will change the licensing basis for the plant by referencing NEI 94-01, Revision 3-A, in TS 5.5.12, "10 CFR 50, Appendix J, Testing Program."

Per the above, Section 11.3.2 of NEI 94-01, Revision 3-A, requires at least two successive tests to be successful at the CLB Pa value of 14.8 psig to extend Type Band Type C test intervals beyond 60 months.

a. Does Entergy plan to re-baseline the subset (i.e., 65 percent of 78) of GGNS Containment Type B penetrations currently on 120-month extended performance-based test interval at the EPU peak containment pressure of 14.8 psig?

Will Entergy use the proposed licensing basis criteria of at least two successive, successful Type B penetration tests before increasing the test interval frequency beyond 60 months for this subset of individual containment penetrations?

b. Does Entergy plan to re-baseline the subset (i.e., 58 percent of 121) of GGNS Containment Type C containment isolation valve penetrations currently on 60-month extended performance-based test interval at the EPU peak containment pressure of 14.8 psig?

Will Entergy use the proposed licensing basis criteria of at least two successive, successful Type C containment isolation valve penetration tests before increasing the test interval frequency beyond 60 months for this subset of individual containment penetrations?

LAR Table 3.3.1-2, "Types Band C LLRT Program Implementation Review," Attachment 1 (page 13 of 26), contains a listing of the respective containment isolation valve LLRT failures from the last two refueling outages (RF-18 in 2012 and RF-19 in 2014):

1) With respect to the "Administrative Limit SCCM" column of Table 3.3.1-2, the staff requests clarification for its safety evaluation as to whether the GGNS 10 CFR 50,

Appendix J, Testing Program, already contains individual component administrative limits that are constrained so as to achieve the GGNS administrative summation limit of 0.50 La.

2) LAR Section 3.3.2, "Type Band Type C Tested Components on Extended Intervals,"

reads: "The percentage of the total number of GGNS Type B tested components (78) that are on 120-month extended performance-based test interval is 65%." Based on this, one could conclude that 35 percent of the total population of Type B penetrations did not successfully pass two consecutive Type B tests without failure. However, Table 3.3.1-2 does not list any failures of Type B penetration tests for the two most recent GGNS refueling outages (RF-18 and RF-19). The staff requests that Entergy provide the implied additional historical information about the Type B test failures experienced at GGNS since 2005.

The staff notes that NEI 94-01, Revision 3-A, Section 11.3.1, "Performance Factors," indicates that prior to determining and implementing extended test intervals for Type B and Type C components, an assessment of the plant's containment penetration and valve performance should be performed and documented. Factors that should be considered during the assessment include, but are not limited to: "past component performance"; "service"; "design";

"safety impact"; and "cause determination". However, the technical evaluation section of the LAR does not address how these factors will be incorporated into the GGNS plant-specific 10 CFR 50, Appendix J, Testing Program. The staff requests that Entergy provide the details of how GGNS considered, or plans to consider, these factors in its 10 CFR 50, Appendix J, Testing Program.

ML15261A565 OFFICE DORL/LPLIV-2/PM DORL/LPLIV-2/LA DORL/LPLIV-2/BC DORL/LPLIV-2/PM NAME SKoenick (LRonewicz for) PBlechman MKhanna (SKoenick for) AWang DATE 9/21/2015 9/21/2015 9/23/2015 9/24/2015