ML23222A227

Request for Additional Information Traveler TSTF-592, Revision 1, Revise Automatic Depressurization System (ADS) Instrumentation Requirements

ML23222A227
Person / Time
Site:	Technical Specifications Task Force
Issue date:	08/10/2023
From:	Michelle Honcharik NRC/NRR/DSS/STSB
To:	Technical Specifications Task Force
References
EPID L-2022-PMP-0011
Download: ML23222A227 (7)

Text

August 10, 2023 Technical Specifications Task Force 11921 Rockville Pike, Suite 100 Rockville, MD 20852

SUBJECT:

REQUEST FOR ADDITIONAL INFORMATION RE: TRAVELER TECHNICAL SPECIFICATIONS TASK FORCE -592, REVISION 1, REVISE AUTOMATIC DEPRESSURIZATION SYSTEM INSTRUMENTATION REQUIREMENTS (EPID L-2022-PMP-0011)

Dear Members of the Technical Specifications Task Force:

By letter dated July 19, 2022 (Agencywide Documents Access and Management System Accession No. ML22200A080), you submitted Traveler Technical Specifications Task Force (TSTF)-592, Revision 0, Revise Automatic Depressurization System (ADS) Instrumentation Requirements. In response to the U.S. Nuclear Regulatory Commissions (NRCs) requests for additional information (RAIs), you provided TSTF-592, Revision 1, dated June 27, 2023 (ML23178A184).

Upon review of Revision 1, the NRC staff has determined that additional information is needed.

Mr. Brian Mann, Vice President of Industry Programs, EXCEL Services Corporation, agreed that the NRC staff will receive your response to the enclosed RAI questions within 30 calendar days of the date of this letter.

The review schedule that was provided in the acceptance letter dated September 28, 2022 (ML22256A212), has changed as follows.

MILESTONE DATE Issue Draft Safety Evaluation October 31, 2023 Issue Final Safety Evaluation December 31, 2023 If you have any questions, please contact me at (301) 415-1774 or via email to Michelle.Honcharik@nrc.gov.

Sincerely,

/RA/

Michelle C. Honcharik, Senior Project Manager Technical Specification Branch Division of Safety Systems Office of Nuclear Reactor Regulation Project No. 753

Enclosure:

Request for Additional Information cc: See next page Technical Specifications Task Force Project No. 753 cc:

Technical Specifications Task Force c/o EXCEL Services Corporation 11921 Rockville Pike, Suite 100 Rockville, MD 20852 Attention: Brian D. Mann Email: brian.mann@excelservices.com Drew Richards STP Nuclear Operating Company 12090 FM 521 Mail Code: N5016 Wadsworth, TX 77483 Email: amrichards@stpegs.com Kevin Lueshen Constellation Energy Generation 4300 Winfield Road Warrenville IL 60555 Email: kevin.lueshen@constellation.com Jordan L. Vaughan Duke Energy EC07C / P.O. Box 1006 Charlotte, NC 28202 Email: jordan.vaughan@duke-energy.com Phil H. Lashley Energy Harbor 168 E. Market St.

Akron, OH 44308 Email: phlashley@energyharbor.com Wesley Sparkman Southern Nuclear Operating Company 3535 Colonnade Parkway / Bin N-226-EC Birmingham, AL 35242 Email: wasparkm@southernco.com

ML23222A227 *via email NRR-106 OFFICE NRR/DSS/STSB/BC*

NRR/DSS/STSB/PM*

NAME Vic Cusumano Michelle Honcharik DATE 8/10/2023 8/10/2023

REQUEST FOR ADDITIONAL INFORMATION TECHNICAL SPECIFICATIONS TASK FORCE-592, REVISION 1, REVISE AUTOMATIC DEPRESSURIZATION SYSTEM INSTRUMENTATION REQUIREMENTS (EPID L-2022-PMP-0011)

INTRODUCTION By [[letter::TSTF-23-02, TSTF Response to Request for Additional Information on TSTF-592,Revise Automatic Depressurization System (ADS) Instrumentation Requirements and Submission of Revision 1|letter dated June 27, 2023]] (Agencywide Documents Access and Management System Accession No. ML23178A184), the Technical Specifications Task Force (TSTF) submitted to the U.S. Nuclear Regulatory Commission (NRC) Traveler TSTF-592, Revision 1, Revise Automatic Depressurization System (ADS) Instrumentation Requirements. TSTF-592 would revise Technical Specification (TS) 3.3.5.1, Emergency Core Cooling System (ECCS)

Instrumentation, Actions related to the Automatic Depressurization System (ADS) initiation instrumentation to correct several overly restrictive requirements, and to treat less significant channel inoperabilitys consistently. The proposed change modifies NUREG-1433, Standard Technical Specifications - General Electric BWR/4 Plants, and NUREG-1434, Standard Technical Specifications, General Electric BWR/6 Plants (the STS).

The purpose of the Emergency Core Cooling System (ECCS) instrumentation is to initiate appropriate responses from systems to ensure that the fuel is adequately cooled in the event of a design basis accident or transient.

The ECCS is designed to cool the reactor core following a loss of coolant accident (LOCA). The typical boiling water reactor (BWR) ECCS has low-pressure and high-pressure subsystems. The low-pressure ECCS subsystems are designed to mitigate a large break LOCA where reactor vessel pressure rapidly decreases to the point at which the low-pressure ECCS pumps can inject water. There are two redundant divisions for each of the low-pressure ECCS subsystems.

For example, BWR/4 plants typically have two Low Pressure Coolant Injection (LPCI) subsystems and two Core Spray (CS) subsystems. BWR/6 plants typically have one Low Pressure Core Spray (LPCS) subsystem and three LPCI subsystems. There is a single high-pressure ECCS subsystem. For example, BWR/4 plants have High Pressure Coolant Injection (HPCI), and BWR/6 plants have High Pressure Core Spray. The high-pressure ECCS subsystem is designed to mitigate small break LOCAs during which reactor vessel pressure remains higher than the ability of the low-pressure ECCS pumps to inject water.

The ECCS instrumentation actuates in part, the ADS. The ADS provides redundancy for the single high-pressure ECCS subsystem. In the event of failure of the high-pressure ECCS subsystem, the ADS valves open to rapidly reduce the reactor vessel pressure to the point at which a low-pressure ECCS pump can inject water.

To complete its review of TSTF-592, the NRC staff has determined that additional information is needed. The regulatory basis and the requested additional information are as follows.

Enclosure REGULATORY BASIS FOR REQUEST The regulation at 10 CFR 50.36, Technical specifications, establishes the NRC regulatory requirements related to the content of the TS. 10 CFR 50.36(a)(1) states in part: A summary statement of the bases or reasons for such specification shall also be included in the application but shall not become part of the technical specifications.

10 CFR 50.36(c)(2) states: Limiting conditions for operation are the lowest functional capability or performance levels of equipment required for safe operation of the facility. When a limiting condition for operation of a nuclear reactor is not met, the licensee shall shut down the reactor or follow any remedial action permitted by the technical specifications until the condition can be met.

REQUESTS FOR ADDITIONAL INFORMATION

1. Traveler TSTF-592 Revision 1, Section 3, Technical Evaluation states the following:

Therefore, Required Action H.1 states, Declare ADS valves inoperable when ADS Trip Systems A and B lose initiation capability due to Core Spray/LPCI Discharge Pressure - High channels inoperable.

Traveler TSTF-592, Revision 1, proposed Required Action H.1 does not state what is quoted above. Provide correction to the traveler, as appropriate.

2. Traveler TSTF-592, Revision 1, response to the NRC staffs question (number seven) regarding the Bases expression or tripping appears to have two different outcomes for the same situation. For example, the response states in part, The last sentence of the NUREG-1433 Bases for Required Actions H.1, H.2, and H.3 is revised in the enclosed traveler to state, while allowing time for restoration or tripping of channels. [emphasis added].

It was also noted that in the existing Bases for Required Actions G.1 and G.2 in NUREG-1433 and NUREG-1434, the third paragraphs describe restoration or tripping of channels. Tripping of channels is not a Required Action under Condition G. Therefore, the Bases text is revised to state restoration of channels.

In NUREG-1433 and 1434, "tripping" of channels is also not a proposed Required Action under proposed Condition H. Therefore, provide a justification for including "or tripping" in NUREG-1433 and NUREG-1434 Bases associated with proposed Required Actions H.1, H.2, and H.3.

3. Traveler TSTF-592, Revision 1, Section 2.4, Description of Proposed Change, states the following for the proposed Completion Times associated with proposed Required Action H.2 (BWR/4 and BWR/6 TS 3.3.5.1): The option of including a Risk Informed Completion Time alternative is included but is outside the scope of this traveler to provide the technical justification. The sentence quoted above is confusing. Staff notes that the current Required Action G.2, was approved for use with the risk-informed completion time (RICT) program in TSTF-505. Therefore, the justification was provided in that traveler for including it in the RICT program. Staff notes that proposed Required Action H.2 addresses functions that are proposed to be split off from the current Required Action G.2. Both Completion Times for proposed Required Action H.2 have the option to apply a risk informed completion time and the Completion Times are the same as the current Required Action G.2. For clarity in TSTF-592, provide a similar explanation/justification and a reference to TSTF-505.

4. Traveler TSTF-592, Revision 1, NUREG-1433, TS 3.3.5.1 contains a Note 2 for proposed Required Action H.1 and a Note 2 for proposed Required Action H.2. These Notes are missing the word Pump after Core Spray/LPCI. Including Pump aligns with the applicable Functions identified in Note 1 for proposed Required Action H.1 and Note 1 for proposed Required Action H.2. Provide correction to the traveler (Specs and Bases) as appropriate.

5. Traveler TSTF-592, Revision 1, NUREG-1434, TS 3.3.5.1 contains a Note 2 for proposed Required Action H.1 and a Note 2 for proposed Required Action H.2. These Notes are missing the word Pump after LPCS/LPCI. Including Pump aligns with the applicable Functions identified in Note 1 for proposed Required Action H.1 and Note 1 for proposed Required Action H.2. Provide correction to the traveler (Specs and Bases), as appropriate.

6. Provide correction to the traveler, as appropriate, for the following editorial related items:

a. Traveler Section 2.2, Current Technical Specification Requirements

i. BWR/4 Function 4.f is missing the word discharge (should read Low Pressure Coolant Injection Pump Discharge Pressure - High (emphasis added)).

ii. BWR/4 Function 4.h, 5.h and BWR/6 Function 4.h and 5.g incorrectly refer to Manual Actuation. The STS refer to Manual Initiation.

b. Traveler Section 2.4, Description of Proposed Change

i. BWR/4 proposed Condition H, Required Action H.1 Note 2 and Required Action H.2 Note 2, are missing the word Pump after Core Spray/LPCI.

ii. BWR/6 proposed Condition H, Required Action H.1 Note 2 and Required Action H.2 Note 2, are missing the word Pump after LPCS/LPCI.

c. Traveler Section 3, Technical Evaluation

i. BWR/4 Function 4.f and 5.f are missing the word discharge (should read Low Pressure Coolant Injection Pump Discharge Pressure - High (emphasis added)).

ii. BWR/4 Function 4.h, 5.h and BWR/6 Function 4.h and 5.g incorrectly refer to Manual Actuation. The STS refer to Manual Initiation.

7. Editorial wording differences between BWR/4 and BWR/6 new Action H that should be evaluated and addressed, for the following:

Required Action H.1, Note 2 The BWR/4 RA H.1, Note 2 states in part:... when both ADS Trip Systems are inoperable due to...

The BWR/6 RA H.1, Note 2 states in part: when ADS Trip Systems A and B lose initiation capability due to Is there a rationale for the different wording? If not, when responding to the requests for additional information (RAIs), kindly make them read the same, as appropriate. BWR/4 and BWR/6 wording both appear to be sufficient, but the BWR/6 wording is preferable.

Required Action H.2, Note 2 The BWR/4 RA H.2, Note 2 states in part: when one ADS trip system is inoperable due to The BWR/6 RA H.2, Note 2 states in part: when one ADS trip system loses initiation capability due to Is there a rationale for the different wording? If not, when responding to the RAIs, kindly make them read the same, as appropriate. BWR/4 and BWR/6 wording both appear to be sufficient, but the BWR/6 wording is preferable.

BWR/4 and BWR/6 wording both appear to be sufficient, but the BWR/6 wording is preferable.

Completion Time associated with Required Action H.2 The BWR/4 RA H.2 Completion Time associated with 96 hours0.00111 days <br />0.0267 hours <br />1.587302e-4 weeks <br />3.6528e-5 months <br /> states in part: from discovery of a loss of ADS initiation capability in one trip system concurrent with The BWR/6 RA H.2 Completion Time associated with 96 hours0.00111 days <br />0.0267 hours <br />1.587302e-4 weeks <br />3.6528e-5 months <br /> states in part: from discovery of inoperable channel concurrent with Is there a rationale for the difference? If not, when responding to the RAIs, kindly make them read the same, where appropriate. BWR/4 wording appears to be sufficient and is preferable.

(BWR/6 does not appear to reflect R1 changes)

Note, any change to STS markups should be reflected in descriptions provided in Bases and Traveler Sections 2.4 and 3.