ONS-2017-067, Response to Request for Additional Information Regarding License Amendment Request for TSTF-448, Revision 3, Control Room Habitability, License Amendment Request No. 2015-03, Supplement 2

Response to Request for Additional Information Regarding License Amendment Request for TSTF-448, Revision 3, Control Room Habitability, License Amendment Request No. 2015-03, Supplement 2

ML17292A051
Person / Time
Site:	Oconee
Issue date:	10/16/2017
From:	Teresa Ray Duke Energy Carolinas
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
LAR 2015-03, Supp 2, ONS-2017-067
Download: ML17292A051 (13)

Text

J_~DUKE

~ ENERGY Thomas D. Ray:*

Vice President Oconee Nuclear Station Duke Energy ON01VP I 7800 Rochester Hwy Seneca, SC 29672 o: 864.873.5016

f. 864.873.5791 Tom.Ray@duke-energy.com ONS-2017-067 10 CFR 50.90 October 16, 2017 ATTN: Document Control Desk U. S. Nuclear Regulatory Commission 11555 Rockville Pike Rockville, Maryland 20852 Duke Energy Carolinas, LLC Oconee Nuclear Station, Units 1, 2 and 3 Docket Numbers: 50-269, 50-270, and 50-287 Renewed Operating Licenses: DPR-38, DPR-47, and DPR-55

Subject:

Request for Additional Information Regarding License Amehdment Request for TSTF-448, Revision 3, "Control Room Habitability,"

License Amendment Request No. 2015-03, Supplement 2 On March 30, 2017, as supplemented by letter dated May 11, 2017, Duke Energy Carolinas, LLC (Duke Energy) submitted a License Amendment Request (LAR) requesting the Nuclear Regulatory Commission (NRC) approve adoption of Technical Specification Task Force (TSTF) 448 (Revision 3) titled, "Control Room Habitability." By email dated September 7, 2017, the NRC requested Duke Energy submit additional information associated with the LAR. The enclosure provides the requested information.

Inquiries on this proposed license amendment request should be directed to Stephen C.

Newman, ONS Regulatory Affairs Group, at (864) 873-4388.

I declare under penalty of perjury that the foregoing is true and correct. Executed on October 16,.2017.

Sincerely,

~]J~

. Thomas D. Ray Vice President Oconee Nuclear Station

Enclosure:

Duke Energy Response to NRC Request for Additional Information

Attachment:

Revised and Reprinted TS and TS Bases Pages

License Amendment Request No. 2015-08 Page 2 Supplement 2 October 16, 2017 cc w/enclosure/attachment:

Ms. Catherine Haney, Administrator, Region II U.S. Nuclear Regulatory Commission Marquis One Tower 245 Peachtree Center Ave., NE, Suite 1200 Atlanta, GA 30303-1257 Ms. Audrey L. Klett, Project Manager *

(by electronic mail only)

U.S. Nuclear Regulatory Commission 11555 Rockville Pike Mail Stop 0-08B 1A Rockville, MD 20852-2738 Mr. Eddy Crowe NRC Senior Resident Inspector Oconee Nuclear Station '

Ms. Susan E. Jenkins, Manager, (by electronic mail only: jenkinse@dhec.sc.gov)

Infectious and Radioactive Waste Management, Bureau of Land and Waste Management Department of Health & Environmental Control 2600 Bull Street Columbia, SC 29201

ENCLOSURE Duke Energy Response to NRC Request for Additional Information (RAI)

Enclosure - Duke Energy Response to NRC RAI Page 1 License Amendment Request No. 2015-03, Supplement 2 October 16, 2017 RAl-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 licensee's 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.

Response to RAl-STSB-1 The current technical specifications for the Oconee Nuclear Station (ONS) Control Room Ventilation System (CRVS) booster fans do not include a surveillance requirement to individually flow test each train. Duke Energy is requesting a variance to TSTF-448 Rev. 3 to include a new SR 3.7.9.5 to perform train flow testing that conforms with both the wording and technical justification contained in the Standard Technical Specifications and associated Bases (NUREG 1430, Revision 4):

SURVEILLANCE FREQUENCY SR 3.7.9.5 Verify the system makeup flow rate is ~ 1215 In accordance with the and s 1485 cfm when supplying the control Surveillance Frequency Control room with outside air. Program The proposed TS SR has been revised to match the STS wording and is included in an attachment to this enclosure.

• The following TS Bases for SR 3.7.9.5 remains unchanged from the prior ONS TSTF-448 LAR submittal and is not included in the attachment to this enclosure:

SR 3.7.9.5 This SR verifies the CRVS can supply the CRE with outside air to meet the design requirement. The design flowrate of each booster fan is 1350 cfm +/-10% (i.e., 1215 cfm to 1485 cfm). This lower limit ensures each train is capable of supplying enough air to meet the minimum total system flowrate requirement of 1215 cfm. The 1485 cfm upper limit is required to meet the carbon filter residence time limit of each individual booster fan train (Ref. 5). The frequency is in accordance with the Surveillance

Enclosure - Duke Energy Response to NRC RAI Page 2 License Amendment Request No. 201-5-03, Supplement 2 October 16, 2017 Frequency Control Program. Initial frequency specified in the surveillance frequency list will be 18 months. This frequency is consistent with industry practice and other filtration SRs, and will be managed in accordance with the Surveillance Frequency Control Program.

RAl-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 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.

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 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 - Duke Energy Response to NRC RAI Page 3 License Amendment Request No. 2015-03, Supplement 2 October 16, 2017 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.

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 NRC's 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 licensee's 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

Enclosure - Duke Energy Response to NRC RAI Page 4 License Amendment Request No. 2015-03, Supplement 2 October 16, 2017 Oconee's NRG-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 NRG-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 NRG-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 NRG-approved design basis, the staff requests the licensee to provide the corresponding TS Bases changes with the proposed TS changes.

Response to RAl-ARCB-1 Duke Energy agrees with the NRC concern associated with the TSTF-448 Limiting Condition for Operation (LCO) "NOTE" and proposes the following changes to both the TS and TSB (underlined text has been added):

---

NOTE----------------------------------------------------

The control room envelope (CRE) boundary may be opened intermittently under administrative control if it is confirmed by analysis that the CRE boundary can be restored and the CRE pressurized in time to ensure accident analysis assumptions remain valid.

Similarly, the TS Bases will be revised to account for the added verbiage to the NOTE as follows:

The LCO is modified by a Note allowing the CRE boundary to be opened intermittently under administrative controls. 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, so that the CRE boundary can be restored and the CRE pressurized within 30 minutes to minimize inleakage as assumed in the station's Alternate Source Term (AST) accident analysis. 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 the 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.

The revised TS page to the previously submitted License Amendment Request (LAR) is included in an attachment to this enclosure.

Enclosure - Duke Energy Response to NRC RAI Page 5 License Amendment Request No. 2015-03, Supplement 2

. October 16, 2017 RAl-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 licensee's submittal di"d 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 staff's 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 doesn't 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.

Response to RAl-ARCB-2 The current Technical Specifications (TS) for the Oconee Nuclear Station (ONS) Control Room Ventilation System (CRVS) booster fans credit two (2) 50 percent capacity trains to ensure that the control room remains adequately pressurized. The current ONS TSs and TS Bases contain actions and restoration completion times associated with a breach in the control room boundary (Condition A), and loss of one (1) 50 percent CRVS booster fan train (Condition 8), the loss of both CRVS booster fan trains (Condition C) and two unit shutdown conditions should Conditions A-C not be met (Conditions D and E).

Enclosure - Duke Energy Response to NRC RAI Page 6 License Amendment Request No. 2015-03, Supplement 2 October 16, 2017 The current 50 percent fan licensing basis is associated with keeping the control room pressurized to minimize inleakage after an accident, a concept determined to be potentially unsatisfactory as denoted in Generic Letter 2003-01. By changing to the proposed TS, Duke Energy is fundamentally changing the function of the fans from "pressurization" to "minimizing inleakage."

As described in the original ONS TSTF-448 LAR submittal, Duke Energy proposes to change TS 3. 7.9 to a two (2) 100 percent train system with each individual booster fan train fully capable of ensuring operator safety by maintaining positive pressure control of the control room envelope for the required mission time of 30 days. As such, Duke Energy is requesting a variance to TSTF-448 Rev. 3, to include a change to the current ONS TS 3. 7 .9 Condition A with one (shown below) that aligns with both the wording and technical justification contained in the Standard Technical Specifications and associated Bases (NUREG 1430, Revision 4) that would allow one train to be out of service for up to 7 days.

CONDITION REQUIRED ACTION COMPLETION TIME A. One CRVS Booster Fan A.1 Restore CRVS train to 7 days train inoperable for OPERABLE status.

reasons other than Condition B.

The aforementioned TS change was previously submitted to the NRC and is not changed.

Additionally, the following TS 3.7.9 Condition A Bases remains unchanged from the prior ONS TSTF-448 LAR submittal and is not included in the attachment:

With one CRVS Booster Fan train inoperable for reasons other than an inoperable CRE boundary, action must be taken to restore OPERABLE status within 7 days. In this Condition, the remaining OPERABLE CRVS Booster Fan train is adequate to perform the CRE occupant protection function. However, the overall reliability is reduced because a failure in the OPERABLE CRVS Booster Fan train could result in loss of CRVS function. The 7 day Completion Time is based on the low probability of a OBA occurring during this time period and ability of the remaining booster fan train to provide the required capability.

In addressing the Staff's questions on train redundancy, mission time, inleakage, and filters, for each ONS control room, the CRVS booster fans are fully redundant mechanically but there are some electrical configuration aspects that prevent them from being truly considered fully redundant, e.g., the control dampers on Unit 3 are electrically fed from the same source. A single booster fan train can operate for 30 days following an accident, while pressurizing and maintaining inleakage below 40 cfm. The filter efficiencies are the same and both trains have independent filter beds. Our current Filter Testing Program (from TS 5.5.12) requires a ~99.5%

removal for dioctyl phthalate (DOP) in-place test on HEPA filters, a ~99% removal of halogenated hydrocarbon (R-11) in-place test for carbon adsorbers, and a ~97.5% removal of radioactive methyl iodide for laboratory test of carbon adsorber samples. Recent tests show an actual >99.9% removal rate for DOP and R-11 tests, and a >99.8% carbon sample efficiency.

ATTACHMENT Revised and Reprinted TS and TS Bases Pages

CRVS Booster Fans 3.7.9 SURVEILLANCE REQUIREMENTS (continued)

SURVEILLANCE FREQUENCY SR 3.7.9.5 Verify the system makeup flow rate is <:: 1215 In accordance with the and s 1485 cfm when supplying the control Surveillance Frequency room with outside air. Control Program OCONEE UNITS 1, 2, & 3 3.7.9-5 Amendment Nos. xxx, xxx, & xxx

CRVS Booster Fans 3.7.9

3. 7 PLANT SYSTEMS 3.7.9 Control Room Ventilation System (CRVS) Booster Fans LCO 3.7.9 Two CRVS Booster Fan trains shall be OPERABLE.

---

~---------------------NOTE----------------------------------------------

The control room envelope (CRE) boundary may be opened intermittently under administrative control if it is confirmed by analysis that the CRE boundary can be restored and the CRE pressurized in time to ensure accident analysis assumptions remain valid.

APPLICABILITY: MODES 1, 2, 3, 4, 5, and 6, During movement of recently irradiated fuel assemblies for any unit.

ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME A. One CRVS Booster Fan A.1 Restore CRVS Booster 7 days train inoperable for Fan train to OPERABLE reasons other than status.

Condition B.

B. One or more CRVS B.1 Initiate action to Immediately Booster Fan trains implement mitigating inoperable due to actions.

inoperable CRE boundary in MODE 1, 2, AND 3, or4.

B.2 Verify mitigating actions 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> ensure CRE occupant radiological exposures will not exceed limits and CRE occupants are protected from chemical and smoke hazards.

AND B.3 Restore CRE boundary 90 days to OPERABLE status.

OCONEE UNITS 1, 2, & 3 3.7.9-1 Amendment Nos. xxx, xxx, & xxx

CRVS Booster Fans B 3.7.9 BASES LCO In order for the CRVS Booster Fan trains to be considered OPERABLE, (continued) the CRE boundary must be maintained such that the CRE occupant dose from a large radioactive release does not exceed the calculated dose in the licensing basis consequences analyses for DBAs and that CRE occupants are protected from hazardous chemicals and smoke.

The LCO is modified by a Note allowing the CRE boundary to be opened intermittently under administrative controls. 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, so that the CRE boundary can be restored and the CRE pressurized within 30 minutes to minimize inleakage as assumed in the station's Alternate Source Term (AST) accident analysis. 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 the 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.

APPLICABILITY In MODES 1, 2, 3, 4, 5, and 6, and during movement of recently irradiated fuel assembles for any unit, the CRVS must be OPERABLE to ensure that the CRE will remain habitable during and following a OBA.

During movement of recently irradiated fuel assemblies by any unit, the CRVS Booster Fan trains must be OPERABLE to cope with a release due to a fuel handling accident involving handling recently irradiated fuel. Due to radioactive decay, the CRVS is only required to mitigate fuel handling accidents involving handling recently irradiated fuel (i.e., fuel that has occupied part of a critical reactor core within the previous 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />).

ACTIONS With one CRVS Booster Fan train inoperable for reasons other than an inoperable CRE boundary, action must be taken to restore OPERABLE status within 7 days. In this Condition, the remaining OPERABLE CRVS Booster Fan train is adequate to perform the CRE occuJDant protection function. However, the overall reliability is reduced because a failure in the OPERABLE CRVS Booster Fan train could result in loss of CRVS function. The 7 day Completion Time is based on the low probability of a OBA occurring during this time period and ability of the remaining booster fan train to provide the required capability.

OCONEE UNITS 1, 2, & 3 B 3.7.9-3 Rev. 001 I