ML18143B679

Indian Point, Unit 3 - Request for Additional Information Regarding LAR for One-Time Extension of the Containment Leakage Rate Test - Email from R.Guzman to M.Mirzai (EPID: L-2017-LLA-0406)

ML18143B679
Person / Time
Site:	Indian Point
Issue date:	05/23/2018
From:	Guzman R V Plant Licensing Branch 1
To:	Mirzai M Entergy Nuclear Operations
Guzman R V
References
EPID L-2017-LLA-0406
Download: ML18143B679 (4)

Text

From:Guzman, RichardTo:"Mirzai, Mahvash"Cc:Walpole, Robert W

Subject:

Indian Point, Unit 3 - Request for Additional Information regarding LAR for One-Time Extension of theContainment Leakage Rate Test (EPID: L-2017-LLA-0406)Date:Wednesday, May 23, 2018 2:14:07 PMMahvash, On May 15, 2018, the U.S. Nuclear Regulatory Commission (NRC) staff sent EntergyNuclear Operations, Inc. (Entergy or the licensee) the subject Request for AdditionalInformation (RAI) as a draft (via e-mail shown below). This RAI relates to a licenseamendment request submitted by Entergy that requests a one-time extension to the IndianPoint Unit No. 3 Containment Integrated Leakage Rate Test (from the current 15-year to a16-year frequency). This test is required by Technical Specification 5.5.15 "ContainmentLeakage Rate Testing Program." On May 23, 2018, the NRC staff conducted a conference call with the licensee staff toclarify the request. Following the discussion, you indicated that Entergy will provide aresponse to this RAI by July 6, 2018 (approximately 45 days from the date of thiscorrespondence). Updated below is the official (final) RAI. A publicly available version ofthis e-mail and RAI will be placed in the NRC's ADAMS system. Please contact me shouldyou have any questions in regard to this request. Thanks,~~~~~~~~~Rich GuzmanSr. PM, Division of Operating Reactor LicensingOffice of Nuclear Reactor RegulationU.S. Nuclear Regulatory CommissionOffice: O-9C07 l Phone: 301-415-1030 From: Guzman, Richard [1] Sent: Tuesday, May 15, 2018 12:33 PMTo: Walpole, Robert WCc: Mirzai, Mahvash

Subject:

Indian Point, Unit 3 - LAR for One-Time Extension of the Containment Leakage Rate Test -DRAFT Request for Additional Information (EPID: L-2017-LLA-0406)Mahvash,By letter dated December 8, 2017 (Agencywide Documents Access and ManagementSystem (ADAMS) Accession No. ML17349A131), Entergy Nuclear Operations, Inc.(Entergy, licensee) submitted a license amendment request (LAR) requesting one-timeextension from 15 years to 16 years frequency for the Indian Point Unit No. 3 (IP3)containment Integrated Leakage Rate Test (ILRT). The Nuclear Regulatory Commission(NRC) staff has determined that additional information is needed to complete its review, asdescribed in the request for additional information (RAI) shown below. This RAI is identified as draft at this time to confirm your understanding of the informationthat the NRC staff needs to complete the evaluation. Please contact me if you would like toset up a conference call to clarify this request for information.

Thanks,~~~~~~~~~Rich GuzmanSr. PM, Division of Operating Reactor LicensingOffice of Nuclear Reactor RegulationU.S. Nuclear Regulatory CommissionOffice: O-9C07 l Phone: 301-415-1030 REQUEST FOR ADDITIONAL INFORMATIONLICENSE AMENDMENT REQUEST (LAR)FOR ONE-TIME EXTENSION OF THECONTAINMENT TYPE A LEAK RATE TESTING FREQUENCY FROM 15 TO 16 YEARSINDIAN POINT UNIT NO. 3DOCKET NO. 50-286By letter dated December 8, 2017 (Agencywide Documents Access and ManagementSystem (ADAMS) Accession No. ML17349A131), Entergy Nuclear Operations, Inc.(Entergy, licensee) submitted a license amendment request (LAR) requesting one-timeextension from 15 years to 16 years frequency for the Indian Point Unit No. 3 (IP3)containment Integrated Leakage Rate Test (ILRT). This test is required by TS 5.5.15"Containment Leakage Rate Testing Program." The following requests for additionalinformation (RAIs) outline the information needed for the NRC staff to complete its review:RAI External Events ScreeningElectric Power Research Institute (EPRI) Technical Report No. 1009325, Revision 2-A(ADAMS Accession No. ML14024A045) states that "[w]here possible, the analysis shouldinclude a quantitative assessment of the contribution of external events (for example, fireand seismic) in the risk impact assessment for extended ILRT intervals. For example,where a licensee possesses a quantitative fire analysis and that analysis is of sufficientquality and detail to assess the impact, the methods used to obtain the impact from internalevents should be applied for the external event." EPRI TR-1009325, Revision 2-A furtherstates that the "assessment can be taken from existing, previously submitted and approvedanalyses or another alternate method of assessing an order of magnitude estimate forcontribution of the external event to the impact of the changed interval."In Section 5.7 of Attachment 1 to the LAR, the licensee performed an assessment ofexternal event contribution. The licensee's analysis reflected the contribution from internalfire and seismic event. The licensee stated that high winds, external floods and "Other"external events were considered negligible in estimation of the external events impact onthe ILRT extension application. This conclusion appears to be reached based on the IP3Individual Plant Examination for External Events (IPEEE) analysis performed in 1997.Consistent with the Regulatory Guide (RG) 1.174 guidance that the probabilistic risk assessment (PRA) scope, level of detail and technical acceptability be based on the as-built and as-operated plant, and maintained to reflect the current operating experience atthe plant, provide justification for the applicability of the IPEEE conclusions to the currentplant and its environs, considering each of the external hazards screened from thisapplication and taking into account any updated risk studies and insights. The analysisshould include all hazard groups (i.e., high winds, external flooding, transportation events,aircraft, industrial facilities, and other external hazards)RAI Assumptions used for Alternative Approach for External Events ImpactSection 2.5.3 of RG 1.174, Revision 3, states, "[t]he impact of using alternativeassumptions or models may be addressed by performing appropriate sensitivity studies orby using qualitative arguments, based on an understanding of the contributors to the resultsand how they are impacted by the change in assumptions or models." In addition, Section2.5.5 of RG 1.174 states, "[i]n general, the results of the sensitivity studies should confirmthat the guidelines are still met even under the alternative assumptions (i.e., changegenerally remains in the appropriate region)." In Section 5.7 of Attachment 1 to the LAR, the licensee performed an assessment ofexternal event contribution. The licensee used two approaches: the multiplier approach,which applies a multiplier to the internal events results (the multiplier is derived from theratio of external events core damage frequency (CDF) to the internal events CDF) and an"alternative" approach where each EPRI accident class frequency is re-examined. Thelicensee calculated an increase in population dose risk from changing the ILRT frequencyfrom three in 10 years to once in 16 years as 3.67 person-rem/year or 1.00% (when usingthe multiplier approach) and 3.84 person-rem/year or 0.69% when using the alternativeapproach. The reported increase in total population dose is close to the acceptance criteriavalues of 1 person-rem/year or 1% provided in EPRI TR-1009325, Revision 2-A, anddefined in Section 3.2.4.6 of the NRC safety evaluation for NEI 94-01, Revision 2 (ADAMSAccession No. ML081140105). It appears that the reduction in the % population dose change obtained through the use ofthe "alternative" approach included in Section 5.7.5 of Attachment 1 to the LAR relies onincreasing the total estimated population dose due to external hazards for the base case,corresponding to the three in 10 year frequency. Two assumptions appears to be key tothis reduction in population dose change: ~ The frequency for the EPRI accident Class 7 sequences (accidents involvingcontainment failure induced by severe accident phenomena) is increased byassuming that 50% of the CDF is due to late Class 7 sequences, as compared tothe internal events value of 15%, with the justification that "the external eventscontributors are dominated by unrecoverable SBO-like scenarios". ~ The frequency of the EPRI accident Class 2 sequences (containment isolationfailures) is increased by assuming that 0.1% of the external events CDF is due tolarge containment isolation failures, as opposed to the internal events contribution of0.03%, with the justification that "seismic and fire initiated events would likely be more susceptible" to large containment isolation failures. In accordance with the guidance in RG 1.174, provide a detailed justification for assumingthe value of 50% for the external events contribution to the Class 7 late sequences and thevalue of 0.1% for the Class 2 sequences. The explanation should include the conceptsused to identify the assumptions made for the contributors which ultimately resulted in doserisk change to less than 1.0%. Include a discussion of the conservatisms in the analysisand the risk significance of these conservatisms.