ML17256A123
| ML17256A123 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 09/07/2017 |
| From: | Audrey Klett Plant Licensing Branch II |
| To: | Wasik C Duke Energy Carolinas |
| References | |
| MF9555, MF9556, MF9557 | |
| Download: ML17256A123 (6) | |
Text
1 NRR-PMDAPEm Resource From:
Klett, Audrey Sent:
Thursday, September 07, 2017 3:36 PM To:
Wasik, Christopher J Cc:
Newman, Stephen
Subject:
Request for Additional Information - Oconee Nuclear Station, LAR 2015-03, CAC Nos.
MF9555-MF9557 Attachments:
Oconee RAI - MF9555-57.docx Hi Chris, By application dated March 30, 2017, as supplemented by letter dated May 11, 2017, Duke Energy Carolinas, LLC (the licensee) submitted License Amendment Request No. 2015-03 and proposed changes to the Oconee Nuclear Station, Units 1, 2, and 3 Technical Specifications. The proposed amendments would modify the TSs in accordance with TSTF-448, Revision 3, Control Room Habitability.
During its review of the licensees request, NRC staff determined that it needed more information to complete its review. By email dated August 25, 2017, NRC staff provided the licensee a draft of its request for additional information (RAI). On September 7, 2017, the staff held a clarification call with the licensees staff, and it was determined that no changes to the draft RAI were necessary. As discussed with Mr. Stephen Newman with the licensees staff on September 7, 2017, the staff requests the licensee to respond to the RAI attached to this email on or by October 12, 2017.
Thank you, Audrey Klett Project Manager NRR/DORL/LPLII-1 301-415-0489
Hearing Identifier:
NRR_PMDA Email Number:
3722 Mail Envelope Properties (Audrey.Klett@nrc.gov20170907153600)
Subject:
Request for Additional Information - Oconee Nuclear Station, LAR 2015-03, CAC Nos. MF9555-MF9557 Sent Date:
9/7/2017 3:36:16 PM Received Date:
9/7/2017 3:36:00 PM From:
Klett, Audrey Created By:
Audrey.Klett@nrc.gov Recipients:
"Newman, Stephen" <Stephen.Newman@duke-energy.com>
Tracking Status: None "Wasik, Christopher J" <Christopher.Wasik@duke-energy.com>
Tracking Status: None Post Office:
Files Size Date & Time MESSAGE 1075 9/7/2017 3:36:00 PM Oconee RAI - MF9555-57.docx 36052 Options Priority:
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REQUEST FOR ADDITIONAL INFORMATION OFFICE OF NUCLEAR REACTOR REGULATION LICENSE AMENDMENT REQUEST NO. 2015-03 DUKE ENERGY CAROLINAS, LLC OCONEE NUCLEAR STATION, UNITS 1, 2, AND 3 DOCKET NOS. 50-269, 50-270, AND 50-287 CAC NOS. MF9555, MF9556, AND MF9557 By application dated March 30, 2017, as supplemented by letter dated May 11, 2017 (Agencywide Documents Access and Management System (ADAMS) Accession Numbers ML17095A530 and ML17139D352), Duke Energy Carolinas, LLC (the licensee) submitted License Amendment Request No. 2015-03 and proposed changes to the Oconee Nuclear Station, Units 1, 2, and 3 (Oconee) Technical Specifications (TSs). The proposed amendments would modify the TSs in accordance with Technical Specification Task Force (TSTF)-448, Revision 3, Control Room Habitability (ADAMS Accession No. ML062210095).
During its review of the licensees request, staff from the U.S. Nuclear Regulatory Commissions Technical Specifications Branch (STSB) and Radiation Protection and Consequence Branch (ARCB) determined that it needed more information to complete its review. The staffs request for additional information (RAI) is as follows.
RAI-STSB-1 Title 10 of the Code of Federal Regulations (10 CFR), Part 50, Section 50.90, Application for amendment of license, construction permit, or early site permit, states that license amendment requests must fully describe the changes desired. In Section 2.2 of its submittal dated March 30, 2017, the licensee provided discussions of the variances between the changes described in TSTF-448 and the proposed changes to the Oconee TSs. However, this section does not discuss the licensees proposed addition of Surveillance Requirement (SR) 3.7.9.5, which would state, Verify the makeup flow rate for each booster fan is 1350 cfm +/-10% (i.e.,
1215 cfm to 1485 cfm) when supplying the control room with outside air. SR 3.7.9.5 would have a frequency of In accordance with the Surveillance Frequency Control Program.
TSTF-448 did not add an SR to the Standard TSs (STSs) similar to the proposed SR 3.7.9.5 for the Oconee TSs. Rather, the STSs in NUREG-1430, contained a similar SR (i.e., SR 3.7.10.5) prior to TSTF-448 approval. It appears the licensee proposed the adoption of a plant-specific version of STS SR 3.7.10.5 without fully describing why that is appropriate for the Oconee TSs.
Therefore, the staff requests the licensee to fully describe the proposed Oconee TS SR 3.7.9.5, including a basis for the proposed new SR.
RAI-ARCB-1 Section 50.67, Accident source term, Paragraph 50.67(b)(2) of 10 CFR states that the NRC may issue the amendment only if the applicants analysis demonstrates with reasonable assurance that:
(i) An individual located at any point on the boundary of the exclusion area for any 2-hour period following the onset of the postulated fission product release, would not receive a radiation dose in excess of 0.25 Sv (25 rem)1 total effective dose equivalent (TEDE).
(ii) An individual located at any point on the outer boundary of the low population zone, who is exposed to the radioactive cloud resulting from the postulated fission product release (during the entire period of its passage), would not receive a radiation dose in excess of 0.25 Sv (25 rem) total effective dose equivalent (TEDE).
(iii) Adequate radiation protection is provided to permit access to and occupancy of the control room under accident conditions without personnel receiving radiation exposures in excess of 0.05 Sv (5 rem) total effective dose equivalent (TEDE) for the duration of the accident.
NRC Regulatory Guide (RG) 1.183, Alternative Radiological Source Terms for Evaluating Design Basis Accidents at Nuclear Power Reactors, dated July 2000 (ADAMS Accession No. ML003716792) provides the methodology for analyzing the radiological consequences of several design basis accidents to show compliance with 10 CFR 50.67. RG 1.183 provides guidance to licensees for the acceptable application of alternate source term (AST, also known as the accident source term) submittals, including acceptable radiological analysis assumptions for use in conjunction with the accepted AST.
Section 50.36, Technical Specifications, of 10 CFR requires in part that the TSs be derived from the analyses and evaluation included in the safety analysis report, and amendments thereto, and includes items in following categories: (1) safety limits, limiting safety systems settings, and limiting control settings; (2) limiting conditions for operation (LCOs); (3) SRs; (4) design features; (5) administrative controls; (6) decommissioning; (7) initial notifications; and (8) written reports.
The control room ventilation system (CRVS) booster fan trains provide a protected environment from which operators can control the unit during airborne challenges from radioactivity, hazardous chemicals, and fire byproducts, such as fire suppression agents and smoke, during both normal and accident conditions. The CRVS booster fan trains are designed to maintain a habitable environment in the control room envelope (CRE) for 30 days after a design basis accident without exceeding 5 rem TEDE. The CRVS booster fan trains are designed and credited in the design basis accident analyses to help reduce the radioactive releases to meet the total radiation dose requirements specified in 10 CFR 50.67.
1 The use of 0.25 Sv (25 rem) TEDE is not intended to imply that this value constitutes an acceptable limit for emergency doses to the public under accident conditions. Rather, this 0.25 Sv (25 rem) TEDE value has been stated in this section as a reference value, which can be used in the evaluation of proposed design basis changes with respect to potential reactor accidents of exceedingly low probability of occurrence and low risk of public exposure to radiation.
On June 1, 2004, the NRC issued Amendment Nos. 338, 339, and 339 (ADAMS Accession No. ML041540097) to Renewed Facility Operating Licenses DPR-38, DPR-47, and DPR-55, respectively, for the Oconee Nuclear Station, Units 1, 2, and 3. The amendments revised the TSs to incorporate changes resulting from use of an AST. The licensee re-analyzed the postulated loss-of-coolant accident (LOCA) based on the AST described in NUREG-1465, Accident Source Terms for Light-Water Nuclear Power Plants, dated February 1995 (ADAMS Accession No. ML041040063), and the re-analyzed maximum hypothetical accident is provided in Updated Final Safety Analysis Report (UFSAR), Section 15.15, Maximum Hypothetical Accident. Per the NRCs safety evaluation for Amendments 338, 339, and 339, the licensee re-evaluated the control room habitability with the application of the AST. The licensee assumed that CRVS booster fan trains maintain a positive control room pressure to ensure outward leakage, preventing unfiltered air in leakage into the control room, and assumed a bounding 40 cubic feet per minute unfiltered air in leakage into the control room. Furthermore, the licensee assumed that the control room operator will start the CRVS booster fans within 30 minutes of the DBA, and the analysis concluded that the radiological consequences to the control room operator resulting from the postulated LOCA were within the 5 rem TEDE criterion specified in 10 CFR 50.67.
In its submittal dated March 30, 2017, the licensee proposed to modify the CRVS booster fan LCO by adding a note allowing the CRE boundary to be opened intermittently under administrative controls. The licensee provided LCO Bases with its submittal that state:
This Note only applies to openings in the CRE boundary that can be rapidly restored to the design condition, such as doors, hatches, floor plugs, and access panels. For entry and exit through doors, the administrative control of the opening is performed by the person(s) entering or exiting the area. For other openings, these controls should be proceduralized and consist of stationing a dedicated individual at the opening who is in continuous communication with operators in the CRE. This individual will have a method to rapidly close the opening and to restore the CRE boundary to a condition equivalent to the design condition when a need for CRE isolation is indicated.
Section 50.36 of 10 CFR requires the TSs to be derived from the analyses and evaluation included in the safety analysis report. The licensees proposed LCO note for Oconee TS 3.7.9 does not appear to be consistent with the radiological consequence evaluation for the maximum hypothetical accident in the licensing basis, which assumes that the control room boundary is intact and that a positive pressure is established at 30 minutes after occurrence of the maximum hypothetical accident by its ventilation system. The LCO note would allow the control room boundary to be opened indefinitely. The LCO note as currently proposed would not ensure that the dedicated individual will restore the CRE boundary to a condition equivalent to the design condition within the timing assumed in the radiological consequence analysis for maximum hypothetical accident. The current wording of the LCO note could lead to operation outside of Oconees NRC-approved licensing basis because it does not ensure mitigation of the radioactive releases will occur as assumed in the licensing basis.
Therefore, the staff requests the licensee to justify why the LCO note for TS 3.7.9 is not consistent with the NRC-approved design basis as provided in Amendments 338, 339, and 339 dated June 1, 2004, and as reflected in UFSAR Chapter 15, Accident Analyses. Alternatively, the staff requests the licensee to provide an LCO note for TS 3.7.9 that is consistent with the NRC-approved design basis or a revised radiological consequence analyses for the fuel handling accident and maximum hypothetical accident that does not assume credit of filtration by the control room ventilation system. If the licensee chooses to supplement its application with a revised LCO note that is consistent with the NRC-approved design basis, the staff requests the licensee to provide the corresponding TS Bases changes with the proposed TS changes.
RAI-ARCB-2 Currently, if one CRVS booster fan train is inoperable for reasons other than Condition A (CRE boundary is operable), then existing Action B would apply and require restoring the train to operable status in 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. The licensee proposes to re-letter this Action from B to A, and re-letter the reference Condition from A to B. In addition, the licensee proposes to extend the completion time from 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to 7 days. However, TSTF-448 did not extend or change the completion time. The licensees submittal did not identify this extension to the completion time as a deviation from TSTF-448, nor did it provide a technical justification for this deviation.
The current TS bases for Action B state, The 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> Completion Time is based on the low probability of an accident occurring during this time period, and ability of the remaining train to provide some dose reduction. During the staffs comparison of the Oconee design to that assumed for the STSs, the staff identified that the TS Bases and UFSAR imply that both 50 percent capacity outside air booster fans are needed to perform the design function, which is not consistent with the design assumed for the STSs. Because the UFSAR doesnt clearly explain what was assumed in the AST, the staff could not ascertain whether the licensee analyzed the radiological consequence analysis for operation of only one train.
Therefore, the staff requests the licensee to provide a justification for the proposed completion time extension from 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to 7 days that also includes an explanation of the following:
If the CRVS booster fan trains are fully redundant, If one CRVS booster fan train can perform the specified safety functions assumed in the DBA radiological consequence analysis for the maximum hypothetical accident.
Specifically, the staff requests the licensee to explain whether a single train can:
operate for 30 days following a postulated maximum hypothetical accident, maintain a positive control room pressure to ensure outward leakage, thereby preventing unfiltered air in leakage into the control room from exceeding the assumed 40 cfm, and provide the filter efficiencies of 99 percent for aerosol and elemental iodine and 95 percent for organic iodine assumed in the radiological consequence analysis.