CP-202300470, (Cpnpp), Application to Revise Technical Specifications to Adopt TSTF-589, Eliminate Automatic Diesel Generator Start During Shutdown

(Cpnpp), Application to Revise Technical Specifications to Adopt TSTF-589, Eliminate Automatic Diesel Generator Start During Shutdown

ML24059A386
Person / Time
Site:	Comanche Peak
Issue date:	02/28/2024
From:	John Lloyd Luminant, Vistra Operations Company
To:	Office of Nuclear Reactor Regulation, Document Control Desk
References
CP-202300470, TXX-23077
Download: ML24059A386 (1)

Text

Jay J. Lloyd Comanche Peak Senior Director, Nuclear Power Plant Engineering & Regulatory Affairs (Vistra Operations Company LLC)

P.O. Box 1002 6322 North FM 56 Glen Rose, TX 76043

T 254.897.5337

CP-202300470 TXX-23077 February 28, 2024

ATTN: Document Control Desk Ref 10 CFR 50.90 U.S.NuclearRegulatoryCommission Washington, DC 20555-0001

Subject:

Comanche Peak Nuclear Power Plant (CPNPP)

Docket Nos. 50-445 and 50-446 Application to Revise Technical Specifications to Adopt TSTF-589, "Eliminate Automatic Diesel Generator Start During Shutdown"

Dear Sir or Madam:

Pursuant to 10 CFR 50.90, Vistra Operations Company LLC (Vistra OpCo) is submitting a request for an amendment to the Technical Specifications (TS) for Comanche Peak Nuclear Power Plant (CPNPP),

Units 1 and 2.

Vistra OpCo requests adoption of TSTF-589, "Eliminate Automatic Diesel Generator Start During Shutdown," which is an approved change to the Standard Technical Specifications (STS), into the Comanche Peak Nuclear Power Plant (CPNPP), Units 1 and 2 TS. TSTF-589 eliminates the TS requirements for automatic diesel generator (DG) start and loading during shutdown.

The enclosure provides a description and assessment of the proposed changes. Attachment 1 provides the existing TS pages marked to show the proposed changes. Attachment 2 provides revised (clean) TS pages. Attachment 3 provides the existing TS Bases pages marked to show revised text associated with the proposed TS changes and is provided for information only.

Vistra OpCo requests that the amendment be review ed under the Consolidated Line Item Improvement Process (CLIIP). Approval of the proposed amendment is requested within 6 months of completion of the NRCs acceptance review. Once approved, the amendment shall be implemented within 90 days.

In accordance with 10 CFR 50.91, a copy of this app lication, with attachments, is being provided to the designated State Official.

This communication contains no new commitments regarding CPNPP Units 1 and 2.

Should you have any questions, please co ntact Nic Boehmisch at (254) 897-5064 or nicholas.boehmisch@luminant.com.

TXX-23077 Page 2 of 2 I state under penalty of perjury that the foregoing is true and correct.

Executed on February 28, 2024.

Sincerely, Jay J. Lloyd

Enclosure:

Description and Assessment Attachments: 1. Proposed Technical Specification Changes (Mark-Up) 2.Revised Technical Specification Pages 3.Proposed Technical Specification Bases Changes (Mark-Up) -For Information Only c (email) - John Monninger, Region IV [John.Monninger@mc.gov]

Samson Lee, NRR [Samson.Lee@mc.gov]

John Ellegood, Senior Resident Inspector, CPNPP Uohn.Ellegood@mc.gov]

Hemy Strittmatter, Resident Inspector, CPNPP [Hemy.Strittmatter@mc.gov]

Mr. Robert Free [robert.free@dshs.state.tx.us]

Environmental Monitoring & Emergency Response Manager Texas Department of State Health Services Mail Code 1986 P.0. Box 149347 Austin TX, 78714-9347 Enclosure to TXX-23077 Page 1 of 3

DESCRIPTION AND ASSESSMENT

1.0 DESCRIPTION

Vistra Operations Company LLC (Vistra OpCo) requests adoption of TSTF-589, "Eliminate Automatic Diesel Generator Start During Shutdown," which is an approved change to the Standard Technical Specifications (STS), into the Comanche Peak Nuclear Power Plant (CPNPP) Units 1 and 2 TS. TSTF-589 eliminates the TS requirements for automatic diesel generator (DG) start and loading during shutdown.

2.0 ASSESSMENT

2.1 Applicability of Safety Evaluation

Vistra OpCo has reviewed the safety evaluation for TSTF-589 provided to the Technical Specifications Task Force in a letter dated September 11, 2023. This review included a review of the NRC staffs evaluation, as well as the info rmation provided in TSTF-589. Vistra OpCo has concluded that the justifications presented in TSTF-589 and the safety evaluation prepared by the NRC staff are applicable to Comanche Peak Nuclear Power Plant (CPNPP) Units 1 and 2, and justify this amendment for the incorpor ation of the changes to the CPNPP TS.

The existing TS 3.8.2, "AC Sources - Shutdown" requirements are applicable in Modes 5 and 6 but, unlike the STS, are not applicable during movement of irradiated fuel. This does not affect the applicability of the traveler to the CPNPP TS.

The existing SR 3.8.2.1 differs from the STS SR 3.8.2.1. The existing SR 3.8.2.1 lists the TS 3.8.1 SRs that are applicable instead of the 3.8.1 SRs that are not applicable. This difference does not affect the applicability of the traveler to the CPNPP TS.

2.2 Variations

Vistra OpCo is proposing the following variations from the TS changes described in TSTF-589 or the applicable parts of the NRC staffs safety evaluation:

The existing TS 3.3.5, "LOP DG Start Instrumentation," specification is not applicable when LCO 3.8.2, "AC Sources - Shutdown," is applicable. Therefore, the change to the TS 3.3.5 Applicability is not included in the proposed change.

The existing SR 3.8.2.1 differs from the STS SR 3.8.2.1. The existing SR 3.8.2.1 contains differences in the applicable 3.8.1 SRs which must be met or performed. The existing SR 3.8.2.1 does not require SR 3.8.1.11.c.2, SR 3.8.1.13, and SR 3.8.1.18 to be met or performed. These differences do not affect the applicability of the traveler to the CPNPP TS.

Enclosure to TXX-23077 Page 2 of 3

3.0 REGULATORY ANALYSIS

3.1 No Significant Hazards Consideration Analysis

Vistra OpCo requests adoption of TSTF-589, "Eliminate Automatic Diesel Generator Start During Shutdown," which is an approved change to the Standard Technical Specifications (STS), into the Comanche Peak Nuclear Power Plant (CPNPP) Units 1 and 2 Technical Specifications (TS).

TSTF-589 eliminates the TS requirements for automatic diesel generator (DG) start and loading during shutdown.

Vistra OpCo has evaluated if a significant haza rds consideration is involved with the proposed amendment(s) by focusing on the three standards set forth in 10 CFR 50.92, "Issuance of amendment," as discussed below:

1. Does the proposed amendment involve a significant increase in the probability or consequences of an accident previously evaluated?

Response: No

The proposed change eliminates the TS requirements for automatic DG start and loading during shutdown.

The proposed change does not alter any design function assumed in the accident analysis or the capability of any structure, system, or component (SSC) of the plant to perform a design function assumed in the accident analysis. The analysis of accidents initiated during shutdown does not assume a loss of offsite power or the automatic start and loading of a DG during shutdown. Therefore, the proposed change does not affect the probability of an accident previously evaluated. Automatic detection of a loss of power, automatic load shedding of the Engineering Safety Feature (ESF) busses, and automatic start and loading of a DG onto the ESF busses is not assumed to mitigate the consequences of any previously evaluated accident initiated duri ng shutdown. As a result, there is no impact on the consequences of any accident previously evaluated.

Therefore, the proposed change does not involve a significant increase in the probability or consequences of an accident previously evaluated.

2. Does the proposed amendment create the possibi lity of a new or different kind of accident from any accident previously evaluated?

Response: No

The proposed change eliminates the TS requirements for automatic DG start and loading during shutdown.

The proposed change does not affect the ability of any SSC to perform the design functions assumed in the accident analysis. The proposed change does not create any credible new failure mechanisms, malfunctions, or accident initiators not considered in the Enclosure to TXX-23077 Page 3 of 3

design and licensing bases that would have been considered a design basis accident in the Updated Final Safety Analysis Report (UFSAR) had it been previously identified.

Therefore, the proposed change does not create the possibility of a new or different kind of accident from any accident previously evaluated.

3. Does the proposed amendment involve a significant reduction in a margin of safety?

Response: No

The proposed change eliminates the TS requirements for automatic DG start and loading during shutdown.

The proposed change does not alter a design basis or safety limit (i.e., the controlling numerical value for a parameter established in the UFSAR or the license) and does not affect any conservatism in the evaluation and analysis methods that are used to demonstrate compliance with regulatory and licensing requirements. As a result, the margin of safety is not reduced.

Therefore, the proposed change does not involve a significant reduction in a margin of safety.

Based on the above, Vistra OpCo concludes that the proposed change presents no significant hazards consideration under the standards set forth in 10 CFR 50.92(c), and, accordingly, a finding of "no significant hazards consideration" is justified.

3.2 Conclusion

In conclusion, based on the considerations discussed above, (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the Commissions regulations, and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.

4.0 ENVIRONMENTAL CONSIDERATION

A review has determined that the proposed amendment would change a requirement with respect to installation or use of a facility component located within the restricted area, as defined in 10 CFR 20, or would change an inspection or surveillance requirement. However, the proposed amendment does not involve (i) a significant hazards consideration, (ii) a significant change in the types or a significant increase in the amounts of any effluents that may be released offsite, or (iii) a significant increase in individual or cumulative occupational radiation exposure.

Accordingly, the proposed amendment meets the eligibility criterion for categorical exclusion set forth in 10 CFR 51.22(c)(9). Therefore, pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the proposed amendment.

Attachment 1 to TXX-23077

Proposed Technical Specification Changes (Mark-Up)

AC Sources - Shutdown 3.8.2

ACTIONS (continued)

CONDITION REQUIRED ACTION COMPLETION TIME

B. One required DG B.1 Suspend CORE ALTERATIONS. Immediately inoperable.

AND

B.2 Suspend movement of irradiated fuel Immediately assemblies.

AND

B.3 Suspend operations involving Immediately positive reactivity additions that could result in loss of required SDM or boron concentration.

AND

B.4 Initiate action to restore required DG Immediately to OPERABLE status.

SURVEILLANCE REQUIREMENTS

SURVEILLANCE FREQUENCY

---

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

The following SRs are not required to be performed: SR 3.8.1.3, SR 3.8.1.9, through SR 3.8.1.101, SR 3.8.1.14, SR 3.8.1.15, and SR 3.8.1.16.

The following SRs are applicable for SR 3.8.2.1 For AC sources required to be OPERABLE, the following In accordance with SRs are applicable: applicable SRs

SR 3.8.1.1 SR 3.8.1.5 SR 3.8.1.10 SR 3.8.1.2 SR 3.8.1.6 SR 3.8.1.11 (except c.2)

SR 3.8.1.3 SR 3.8.1.7 SR 3.8.1.14 SR 3.8.1.4 SR 3.8.1.9 SR 3.8.1.15 SR 3.8.1.16

COMANCHE PEAK - UNITS 1 AND 2 3.8-20Amendment No. 153, 183 Attachment 2 to TXX-23077

Revised Technical Specification Pages AC Sources - Shutdown 3.8.2

ACTIONS (continued)

CONDITION REQUIRED ACTION COMPLETION TIME

B. One required DG B.1 Suspend CORE ALTERATIONS. Immediately inoperable.

AND

B.2 Suspend movement of irradiated fuel Immediately assemblies.

AND

B.3 Suspend operations involving Immediately positive reactivity additions that could result in loss of required SDM or boron concentration.

AND

B.4 Initiate action to restore required DG Immediately to OPERABLE status.

SURVEILLANCE REQUIREMENTS

SURVEILLANCE FREQUENCY

---

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

The following SRs are not required to be performed: SR 3.8.1.3, SR 3.8.1.9, SR 3.8.1.10, SR 3.8.1.14, and SR 3.8.1.16.

SR 3.8.2.1 The following SRs are applicable for AC sources In accordance with required to be OPERABLE: applicable SRs

SR 3.8.1.1 SR 3.8.1.5 SR 3.8.1.14 SR 3.8.1.2 SR 3.8.1.6 SR 3.8.1.16 SR 3.8.1.3 SR 3.8.1.9 SR 3.8.1.4 SR 3.8.1.10

COMANCHE PEAK - UNITS 1 AND 2 3.8-20Amendment No. 153, 183 Attachment 3 to TXX-23077

Proposed Technical Specification Bases Changes (Mark-Up)

- For Information Only AC Sources - Shutdown B 3.8.2

BASES (continued)

LCO One offsite circuit capable of supplying the onsite Class 1E power distribution subsystem(s) of LCO 3.8.10, "Distribution Systems - Shutdown,"

ensures that all required loads are powered from offsite power. An OPERABLE DG, associated with the distribution system train required to be OPERABLE by LCO 3.8.10, ensures a diverse power source is available to provide electrical power support, assumi ng a loss of the offsite circuit.

Together, OPERABILITY of the required offsite circuit and DG ensures the availability of sufficient AC sources to operate the unit in a safe manner and to mitigate the consequences of postulated events during shutdown (e.g.,

fuel handling accidents).

The qualified offsite circuit must be capable of maintaining rated frequency and voltage, and accepting required loads during an accident, while connected to the Engineered Safety Feature (ESF) bus. Qualified offsite circuits are those that are described in the FSAR and are part of the licensing basis for the unit.

Offsite circuit #1 is fed from the 138 kv switchyard and offsite circuit # 2 is fed from the 345 kv switchyard. Circuit #1 is the preferred source for Unit 2 and alternate source for Unit 1. Circuit # 2 is the preferred source for Unit 1 and alternate source for Unit 2. Each offsite circuit can supply 6.9 kv Train A and Train B ESF busses for both Unit 1 and Unit 2.

The DG must be capable of starting, accelerating to rated speed (441 RPM) and voltage, and connecting to its respective ESF bus on receipt of a bus undervoltage signal. This sequence must be accomplished within 10 seconds. The DG must be capabl e of accepting the required loads manually, and continue to operate until offsite power can be restored to the ESF buses. These capabilities are required to be met from a variety of initial conditions such as DG in standby with the engine hot and DG in standby with the engine at ambient conditions.

The DG must be supporting the train of AC electrical distribution required to be OPERABLE per LCO 3.8.10. The offsite circuit must also support the train of AC electrical distribution required to be OPERABLE per LCO 3.8.10.

When the second AC electrical power distribution train (subsystem) is needed to support redundant required systems, equipment and components, the second train may be energized from any available source. The available source must be Class 1E or another reliable source. The available source must be capable of supplying sufficient AC electrical power such that the redundant components are capable of performing their specified safety function(s) (implicitly required by the definition of OPERABILITY).

Otherwise, the supported components must be declared inoperable and the appropriate conditions of the LCOs for the redundant components must be entered.

(continued)

COMANCHE PEAK - UNITS 1 AND 2 B 3.8-32 Revision 85 AC Sources - Shutdown B 3.8.2

BASES

ACTIONS A.2.1, A.2.2, A.2.3, A.2.4, B.1, B.2, B.3, and B.4 (continued)

concentration (MODE 6). Suspending posi tive reactivity additions that could result in failure to meet the minimum SDM or boron concentration limit is required to assure continued safe operation. Introduction of coolant inventory may allow dilution of the RCS but the source of makeup water is required to contain sufficient boron concentration such that when mixed with the RCS inventory the resulting boron concentration in the RCS meets the minimum SDM or refueling boron concentration. This may result in an overall reduction in RCS boron concen tration, but provides acceptable margin to maintaining subcritical operation. Introduction of temperature changes including temperature increases when operating with a positive MTC must also be evaluated to ensure they do not result in a loss of required SDM.

Suspension of these activities does not preclude completion of actions to establish a safe conservative condition. These actions minimize the probability or the occurrence of postulated events. It is further required to immediately initiate action to restore the required AC sources and to continue this action until restoration is accomplished in order to provide the necessary AC power to the unit safety systems.

The Completion Time of immediately is consistent with the required times for actions requiring prompt attention. The restoration of the required AC electrical power sources should be completed as quickly as possible in order to minimize the time during which the unit safety systems may be without sufficient power.

Pursuant to LCO 3.0.6, the Distribution System's ACTIONS would not be entered even if all AC sources to it are inoperable, resulting in de-energization. Therefore, the Required Actions of Condition A are modified by a Note to indicate that when Condition A is entered with no AC power to the required ESF bus, the ACTIONS for LCO 3.8.10 must be immediately entered. This Note allo ws Condition A to provide requirements for the loss of the offsite circuit, whether or not a train is de-energized.

LCO 3.8.10 would provide the appropriate restrictions for the situation involving a de-energized train.

SURVEILLANCE SR 3.8.2.1 REQUIREMENTS SR 3.8.2.1 requires the SR from LCO 3.8.1 that are necessary for ensuring the OPERABILITY of the AC sources in other than MODES 1, 2, 3, and 4.

Table B 3.8.2-1 discusses the applicability of the 3.8.1 surveillances.

(continued)

COMANCHE PEAK - UNITS 1 AND 2 B 3.8-34 Revision 85 AC Sources - Shutdown B 3.8.2

BASES

SURVEILLANCE REQUIREMENTS (continued)

This SR is modified by a Note. The reason for the Note is to preclude requiring the OPERABLE DG from being paralleled with the offsite power network or otherwise rendered inoperable during performance of SR, and to preclude deenergizing a required 6.9 KV ESF bus or disconnecting a required offsite circuit during performance of SR. With limited AC sources available, a single event could compromise both the required circuit and the DG. It is the intent that these SR must still be capable of being met, but actual performance is not required during periods when the DG and offsite circuit is required to be OPERABLE. Refer to the corresponding Bases for LCO 3.8.1 for a discussion of each SR.

REFERENCES None.

COMANCHE PEAK - UNITS 1 AND 2 B 3.8-35 Revision 85 AC Sources - Shutdown B 3.8.2

Table B 3.8.2-1 (page 1 of 1)

Scope of SR 3.8.2.1

SR APPLICABLE PERFORM COMMENT

3.8.1.1 Yes Yes

3.8.1.2 Yes Yes

3.8.1.3 Yes No Requires DG in synch with grid

3.8.1.4 Yes Yes

3.8.1.5 Yes Yes

3.8.1.6 Yes Yes

3.8.1.7 Yes Yes

3.8.1.8 No No Requires two offsite sources

3.8.1.9 Yes No Load reject test puts DG at risk

3.8.1.10 Yes No Load reject test puts DG at risk

3.8.1.11 Yes No Do not want to load shed OPERABLE bus.

(except c.2)

3.8.1.11 c.2 No No Requires OPERABLE sequencer

3.8.1.12 No No Requires SI signal

3.8.1.13 No No Requires SI signal

3.8.1.14 Yes No Requires operation of OPERABLE DG with grid

3.8.1.15 Yes No Requires operation of OPERABLE DG with grid

3.8.1.16 Yes No Requires operation of OPERABLE DG with grid

3.8.1.17 No No Requires SI signal

3.8.1.18 No No Requires OPERABLE sequencer

3.8.1.19 No No Requires SI signal

3.8.1.20 No No Requires two OPERABLE DGs

3.8.1.21 No No Requires OPERABLE sequencer

3.8.1.22 No No Requires OPERABLE sequencer

COMANCHE PEAK - UNITS 1 AND 2 B 3.8-36 Revision 85