ML17250B017
| ML17250B017 | |
| Person / Time | |
|---|---|
| Site: | Harris  |
| Issue date: | 09/18/2017 |
| From: | Martha Barillas Plant Licensing Branch II |
| To: | Hamilton T Duke Energy Progress |
| Barillas M DORL/LPL2-2 301-415-2760 | |
| References | |
| CAC MF9740 | |
| Download: ML17250B017 (7) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 Ms. Tanya Hamilton Site Vice President Shearon Harris Nuclear Power Plant 5413 Shearon Harris Road M/C HNP01 New Hill, NC 27562-0165 September 18, 2017
SUBJECT:
SHEARON HARRIS NUCLEAR POWER PLANT, UNIT 1 - REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST PROPOSING A NEW SET OF FISSION GAS GAP RELEASE FRACTIONS FOR HIGH BURNUP FUEL RODS THAT EXCEED THE LINEAR HEAT GENERATION RATE LIMIT DETAILED IN REGULATORY GUIDE 1.183, TABLE 3 (CAC NO. MF9740)
Dear Ms. Hamilton:
By application dated May 22, 2017 (Agencywide Documents Access and Management System Accession No. ML17142A411 ), Duke Energy Progress, LLC (the licensee) submitted a license amendment request for the Shearon Harris Nuclear Power Plant, Unit 1, to revise the facility as described in the final safety analysis report to provide gas gap release fractions for high-burnup fuel rods that exceed the 6.3 kW/ft linear heat generation rate limit detailed in Table 3 of Regulatory Guide 1.183, "Alternative Radiological Source Terms for Evaluating Design-Basis Accidents at Nuclear Power Plants."
The U.S. Nuclear Regulatory Commission staff has determined that additional information is needed in order to complete its review. The enclosed request for additional information was e-mailed to the licensee in draft form on August 30, 2017, and a clarification call was held on September 7, 2017. Please note that if a response to this letter is not received by October 30, 2017, or an acceptable alternate date is not provided in writing, we may deny the'application for amendment under the provisions of Title 10 of the Code of Federal Regulations Section 2.108, "Denial of application for failure to supply information."
If you have any questions, please contact me at 301-415-2760 or by e-mail to Martha.Barillas@nrc.gov.
Docket No. 50-400
Enclosure:
Request for Additional Information cc w/enclosure: Distribution via Listserv Sincerely, Martha C. Barillas, Project Manager Plant Licensing Branch 11-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation
REQUEST FOR ADDITIONAL INFORMATION DUKE ENERGY PROGRESS, LLC SHEARON HARRIS NUCLEAR POWER PLANT, UNIT 1 DOCKET NO. 50-400 By application dated May 22, 2017 (Agencywide Documents Access and Management System
{ADAMS) Accession No. ML17142A411 ), Duke Energy Progress LLC (Duke Energy, the licensee), proposed changes to the Shearon Harris Nuclear Power Plant, Unit 1 (Shearon Harris) current licensing basis. The licensee's amendment would revise the facility as described in the Shearon Harris Final Safety Analysis Report (FSAR) to provide gas gap release fractions for high-burnup fuel rods (i.e., greater than 54 gigawatt days per metric ton of uranium (GWD/MTU)) that exceed the 6.3 kilowatt per foot (kW/ft) linear heat generation rate (LHGR) limit detailed in Table 3, "Non-LOCA Fraction of Fission Product Inventory in Gap," of Regulatory Guide (RG) 1.183, "Alternative Radiological Source Terms for Evaluating Design-Basis Accidents at Nuclear Power Plants," July 2000.
The U.S. Nuclear Regulatory Commission (NRC) staff has reviewed the license amendment request (LAA) and has the following requests for additional information.
Regulatory Analysis Basis Title 1 O of the Code of Federal Regulations (10 CFR) Section 50.67, "Accident source term,"
paragraph (b)(2), states that the NRC may issue the amendment only if the applicant's 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.
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.
Enclosure RG 1.183 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 on 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 that the technical specifications (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; (3) surveillance requirements; (4) design features; (5) administrative controls; (6) decommissioning; (7) initial notifications; and (8) written reports.
Request for Additional Information #1 Duke Energy's LAR proposes gap release fractions for high-burnup fuel rods (i.e., greater than 54 GWD/MTU) that exceed the 6.3 kW/ft LHGR limit in footnote 11 of Table 3 in RG 1.183. The non-loss-of-coolant (LOCA) accident gap fractions stated in Table 3 of RG 1.183 are applied to the non-LOCA accidents if fuel failure occurs during the accident. The following accidents at Shearon Harris assume fuel failure: fuel handling accident, locked rotor accident, and control rod ejection accident. In the LAR, the licensee states that no non-LOCA accidents that may result in departure from nucleate boiling are considered (e.g., locked rotor accident, control rod ejection accident) because the fuel cycles for Shearon Harris will be designed so that no fuel rod predicted to enter departure from nucleate boiling will have been operated beyond the current limit in RG 1.183, footnote 11, for maximum LHGR. However, the LAR does not incorporate this new design requirement into the licensing basis as reflected in the FSAR, nor does it place a requirement in the Shearon Harris TSs such as Section 5.0, "Design Features,
or any other document controlled under 10 CFR 50.59 such as the core operating limits report.
Describe how Duke Energy will incorporate the new design requirement into the Shearon Harris licensing basis as reflected in the FSAR, TSs, or any other document controlled under 10 CFR 50.59 (such as the core operating limits report) or provide the revised radiological consequence analyses for the other design-basis accidents that assume fuel failure (such as locked rotor accident, control rod ejection accident, etc.), which demonstrate that the regulatory limits will be met with the new proposed gap fractions for high-burnup fuel rods.
Request for Additional Information #2 The Shearon Harris FSAR, Section 15.7.4.2.3, "Postulated Fuel Handling Accident in Containment," states:
... The activity released from the damaged assembly is released to the outside atmosphere through the containment openings (such as the personnel airlock door or equipment hatch)... No credit is taken for isolation of containment for the
[fuel handling accident] FHA in containment.
Shearon Harris TS 3.9.4 allows at least three different configurations during core alterations and during movement of irradiated fuel within containment. Three possible configurations are:
(1) equipment door is open and is capable of being closed and held in place by a minimum of four bolts, and each airlock with a minimum of one door closed; (2) equipment door closed and held in place by a minimum of four bolts, and each airlock open with a minimum of one door in the airlock capable of being closed; and (3) equipment door is open and is capable of being closed and held in place by a minimum of four bolts and each airlock open with a minimum of one door in airlock capable of being closed.
Duke Energy submitted a revised fuel handling accident (FHA) in containment analysis that does not specify the configuration of the equipment door and each airlock to demonstrate the most bounding condition. The NRG staff did not find a discussion or analysis provided that explains that the resultant radiological doses provided in the LAR for the FHA in containment bound all the possible configurations. It appears, depending on the plant building configuration, that the open airlocks could allow a pathway for activity to migrate from the open containment airlocks into the adjacent building and eventually into the control room.
- a. Specify all the possible configurations of the equipment door and each airlock.
Provide the rate of release for the equipment door and each airlock that support a 2-hour release to the environment and demonstrate 10 CFR 50.67 radiation dose limit (or exposure to personnel) is met and describe how this analysis bounds all possible configurations of the equipment door and each airlock for the FHA in containment.
- b. Explain if a pathway for activity to migrate from the open containment airlock into the adjacent building and eventually into the control room during ingress/egress of personnel is possible at Shearon Harris following an FHA event in containment. If this pathway is possible, provide additional information describing how this potential dose contribution pathway to the control room is accounted for or bounded by the analysis provided in the LAR.
Request for Additional Information #3 Section 15.7.4.2.2, "Postulated Fuel Handling Accident in the FHB, of the Shearon Harris FSAR contains the radiological consequence analysis of a postulated FHA in the fuel handling building (FHB). In this analysis, credit is taken for removal of iodine by filters during the operation of the spent fuel pool ventilation system. The spent fuel pool area ventilation system is a part of the FHB heating ventilating and air conditioning system. FSAR 6.5.1.2.1, "FHB Emergency Exhaust System, states:
... Following a fuel handling accident radioactivity released from fuel rods will be detected by the radiation monitors located around the fuel pools. These radiation monitors will then signal the switchover from the normal to the emergency ventilation and filtration system. The switchover time is 30 seconds for the emergency ventilation and filtration system to become fully operational. The isolation of the normal ventilation system is accomplished in ::> 1 O seconds.
Either train may then be manually de-energized from the Control Room and placed on standby. Negative pressure is established at 1/8 in. wg. by continuously exhausting air from the operating floor... Assuming the maximum distance traveled by the FHA radioactive gas is half the total distance to the exhaust register, the resulting travel time is 13.65 seconds. This is the longest time considered possible before the radiation detectors initiate an alarm signal to isolate...
Shearon Harris TS Limiting Condition for Operation (LCO) 3/4.9.12, "Fuel Handling Building Emergency Exhaust System, requires two independent FHB emergency exhaust system trains to be operable. TS LCO 3.9.12 has a footnote that states, "The Fuel Handling Building Emergency Exhaust System boundary may be opened intermittently under administrative controls." Section 50.36 of 1 O CFR requires that the TSs be derived from the analyses and evaluation included in the safety analysis report.
The footnote to TS LCO 3/4.9.12 is not consistent with the licensing basis radiological consequence analysis of the postulated FHA in the FHB for Shearon Harris, which assumes the FHB emergency exhaust system is established with a negative internal pressure within 1 minute after occurrence of an FHA in the FHB. The footnote allows the FHB emergency exhaust system boundary to be open for an indefinite length of time, in addition to its unlimited use.
The NRC staff requests one of the following:
- a. Provide a revised radiological consequence analysis of the FHA in the FHB that supports the FHB emergency exhaust system boundary being open for the duration of the event and has radiological dose results that meet the limits in 10 CFR 50.67 and General Design Criteria 19 of 1 O CFR 50, Appendix A. In addition, provide the inputs, assumptions, methodology, and technical basis for the revised analysis.
- b. Provide a proposed change to TS 3.9.12 that is consistent with the design basis as reflected in the Shearon Harris FSAR, Sections 15.7.4.2.2 and 6.5.1.2.1.
SUBJECT:
SHEARON HARRIS NUCLEAR POWER PLANT, UNIT 1 - REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST PROPOSING A NEW SET OF FISSION GAS GAP RELEASE FRACTIONS FOR HIGH BURNUP FUEL RODS THAT EXCEED THE LINEAR HEAT GENERATION RATE LIMIT DETAILED IN REGULATORY GUIDE 1.183, TABLE 3 (CAC NO. MF9740) DATED SEPTEMBER 18, 2017 DISTRIBUTION:
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