ML24165A264

License Amendment Request for Proposed Changes to the Technical Specification Isolation Actuation Instrumentation Tables and New Turbine Enclosure Main Steam Line Tunnel Temperature TS 3/4.7.9

ML24165A264
Person / Time
Site:	Limerick   (NPF-039, NPF-085)
Issue date:	06/13/2024
From:	David Helker Constellation Energy Generation
To:	Office of Nuclear Reactor Regulation, Document Control Desk
References
Download: ML24165A264 (1)

Text

10 CFR 50.90 June 13, 2024 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Limerick Generating Station, Units 1 and 2 Renewed Facility Operating License Nos. NPF-39 and NPF-85 NRC Docket Nos. 50-352 and 50-353

Subject:

License Amendment Request for Proposed Changes to the Technical Specification Isolation Actuation Instrumentation Tables and New Turbine Enclosure Main Steam Line Tunnel Temperature TS 3/4.7.9

Reference:

Constellation Energy Generation, LLC (CEG) letter to the U.S. Nuclear Regulatory Commission (NRC), License Amendment Request to Revise the Licensing and Design Basis to Incorporate the Replacement of Existing Safety-Related Analog Control Systems with a Single Digital Plant Protection System (PPS), (ADAMS Accession No. ML22269A569, dated September 26, 2022).

In accordance with 10 CFR 50.90, "Application for amendment of license, construction permit, or early site permit," Constellation Energy Generation, LLC (CEG), proposes changes to the Technical Specifications (TS), Appendix A of Renewed Facility Operating License Nos. NPF-39 and NPF-85 for Limerick Generating Station (Limerick), Units 1 and 2, respectively.

The proposed change removes Function 1.g, "Turbine Enclosure - Main Steam Line Tunnel Temperature - High," and inserts the word "Deleted" in the following tables: Table 3.3.2-1 Isolation Actuation Instrumentation, Table 3.3.2-2, "Isolation Actuation Instrumentation Setpoints," Table 3.3.2-3, "Isolation System Instrumentation Response Time," and Table 4.3.2.1-1, Isolation Actuation Instrumentation Surveillance Requirements." Deletion of Function 1.g does not require modification to any Actions or Surveillance Requirements.

The proposed change adds a new Technical Specification 3/4.7.9, "Turbine Enclosure Main Steam Line Tunnel Temperature." The new Limiting Condition for Operation (LCO) 3.7.9 requires the Turbine Enclosure (TE) Main Steam Line (MSL) Tunnel maximum temperature to be 175°F. The specification is applicable in Operational Conditions 1, 2, and 3, the same as existing Function 1.g. Surveillance Requirement (SR) 4.7.9.1 requires verification that the TE MSL tunnel temperature is 175°F on a frequency controlled by the Surveillance Frequency Control Program (SFCP). The initial frequency will be 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

In the proposed TS, if the TE MSL tunnel maximum temperature exceeds 175°F, the Action requires immediate action to verify that no MSL pressure boundary leak exists, and periodic verification every 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> thereafter. If it cannot be verified that there is no MSL pressure

License Amendment Request Proposed Changes to TE-MSL Temperature Isolation Signal Docket Nos. 50-352 and 50-353 June 13, 2024 Page 2 boundary leakage or if the periodic verification is not performed, a plant shutdown is required.

The plant must be in Operational Condition 3 (Hot Shutdown) within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and Operational Condition 4 (Cold Shutdown) within the following 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

It is important to note that these proposed changes have been previously submitted by CEG in the Referenced License Amendment Request dated September 26, 2022, which is currently under NRC review. However, this current LAR is considered a duplicate request and is necessary due to the delay in the installation of the new Plant Protection Systems (PPS) to the 2026 Unit 1 Refueling Outage and the 2027 Unit 2 Refueling Outage. Further, this duplicate request is necessary to expedite addressing the issues of main steam tunnel high temperatures during the intervening hot summers that challenge approaching the Main Steam Line Group 1 isolation high temperature trip setpoint, which could result in a reactor trip.

Accordingly, CEG requests the NRC to break out the TS 3/4.7.9 and TS Function 1.g setpoint deletion portion of the Reference LAR and review the proposed changes independently under this submittal. The content of the Referenced LAR proposed changes has been extracted from the Referenced LAR and placed within Attachment 1 of this submittal. There are no nomenclature or acronym differences between the Referenced LAR and this current requested LAR. A minor enhancement was made to the proposed new TS 3/4.7.9 to clarify pressure boundary leakage.

The proposed TS changes will be implemented on existing General Electric (GE) NUMAC leak detection equipment. When the new Plant Protection System (PPS) is installed under the Referenced LAR, the new PPS will maintain the same deleted TS 1.g Function but will be replacing the existing GE leak detection equipment.

CEG has concluded that the proposed changes present no significant hazards consideration under the standards set forth in 10 CFR 50.92, "Issuance of amendment."

The proposed changes have been reviewed by the Limerick Plant Operations Review Committee in accordance with the requirements of the CEG Quality Assurance Program.

This amendment request contains no regulatory commitments.

provides the evaluation of the proposed changes. Attachment 2 provides a copy of the marked-up TS pages that reflect the proposed changes. Attachment 3 provides a copy of the marked-up TS Bases (for information only).

CEG requests approval of the proposed amendments on an expedited basis to avoid anticipated challenges to plant operation by mid-summer. Upon NRC approval, the amendments shall be implemented within 30 days of issuance.

In accordance with 10 CFR 50.91, "Notice for public comment; State consultation," paragraph (b), CEG is notifying the Commonwealth of Pennsylvania of this application for license amendment by transmitting a copy of this letter and its attachments to the designated State Official.

Should you have any questions concerning this submittal, please contact Steve Flickinger at 267-533-5302.

License Amendment Request Proposed Changes to TE-MSL Temperature Isolation Signal Docket Nos. 50-352 and 50-353 June 13, 2024 Page 3 I declare under penalty of perjury that the foregoing is true and correct. Executed on the 13th day of June 2024.

Respectfully, David P. Helker Sr. Manager, Licensing Constellation Energy Generation, LLC Attachments:

1.

Evaluation of Proposed Changes 2.

Markup of Proposed Technical Specification Pages 3.

Markup of Proposed Technical Specification Bases (For Information Only) cc:

Regional Administrator - NRC Region I w/ attachments NRC Senior Resident Inspector - Limerick Generating Station NRC Project Manager, NRR - Limerick Generating Station Director, Bureau of Radiation Protection - Pennsylvania Department of Environmental Protection

ATTACHMENT 1 License Amendment Request Limerick Generating Station, Units 1 and 2 Docket Nos. 50-352 and 50-353 EVALUATION OF PROPOSED CHANGES

Subject:

License Amendment Request for Proposed Changes to the Technical Specification Isolation Actuation Instrumentation Tables and New Turbine Enclosure Main Steam Line Tunnel Temperature TS 3/4.7.9 1.0

SUMMARY

DESCRIPTION 2.0 DETAILED DESCRIPTION

4.0 REGULATORY EVALUATION

4.1 Applicable Regulatory Requirements/Criteria 4.2 Precedents 4.3 No Significant Hazards Consideration 4.4 Conclusions

6.0 REFERENCES

License Amendment Request Proposed Changes to TE-MSL Tunnel Temperature Isolation Signal Docket Nos. 50-352 and 50-353 2

1.0

SUMMARY

DESCRIPTION In accordance with 10 CFR 50.90, "Application for amendment of license, construction permit, or early site permit," Constellation Energy Generation, LLC (CEG), proposes changes to the Technical Specifications (TS), Appendix A of Renewed Facility Operating License Nos. NPF-39 and NPF-85 for Limerick Generating Station (Limerick), Units 1 and 2, respectively.

The proposed change removes Function 1.g, "Turbine Enclosure - Main Steam Line Tunnel Temperature - High," and inserts the word "Deleted" in the following tables: Table 3.3.2-1 Isolation Actuation Instrumentation, Table 3.3.2-2, "Isolation Actuation Instrumentation Setpoints," Table 3.3.2-3, "Isolation System Instrumentation Response Time," and Table 4.3.2.1-1, Isolation Actuation Instrumentation Surveillance Requirements." Deletion of Function 1.g does not require modification to any Actions or Surveillance Requirements.

The proposed change adds a new Technical Specification 3/4.7.9, "Turbine Enclosure Main Steam Line Tunnel Temperature." The new Limiting Condition for Operation (LCO) 3.7.9 requires the Turbine Enclosure (TE) Main Steam Line (MSL) Tunnel maximum temperature to be 175°F. The specification is applicable in Operational Conditions 1, 2, and 3, the same as existing Function 1.g. Surveillance Requirement (SR) 4.7.9.1 requires verification that the TE MSL tunnel temperature is 175°F on a frequency controlled by the Surveillance Frequency Control Program (SFCP). The initial frequency will be 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

In the proposed TS, if the TE MSL tunnel maximum temperature exceeds 175°F, the Action requires immediate action to verify that no MSL leak exists, and periodic verification every 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> thereafter. If it cannot be verified that there is no MSL pressure boundary leakage or if the periodic verification is not performed, a plant shutdown is required. The plant must be in Operational Condition 3 (Hot Shutdown) within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and Operational Condition 4 (Cold Shutdown) within the following 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

The ambient temperature of the monitored TE MSL tunnel area can approach the isolation setpoint for reasons other than actual main steam leaks in the area, such as hot weather, reduced efficiency of the TE compartment area unit coolers, non-safety related HVAC transients, or instrument drift. If both TE MSL Tunnel Temperature - High trip systems were to initiate an isolation signal, a full Group 1 isolation and reactor trip would result. Group 1 isolation closes the Main Steam Isolation Valves (MSIVs), resulting in a loss of heat sink, as well as rendering the main feedwater system unavailable for scram recovery. Such a shutdown would be considered a complicated scram.

The TE - MSL Tunnel Temperature - High Function is not assumed to actuate in any accident analysis. The function is a surrogate for MSL pressure boundary leakage, which is an assumption in some accident analyses. However, creating the potential for a complicated reactor scram based on a surrogate indication, which may not be indicative of actual MSL pressure boundary leakage, is unnecessary. Replacing this automatic MSIV isolation requirement with a monitoring requirement and a manual shutdown if MSL pressure boundary leakage is detected will eliminate the risk of an unnecessary plant transient while still providing the appropriate remedial actions to ensure the plant is operating safely and within the assumed plant conditions.

License Amendment Request Proposed Changes to TE-MSL Tunnel Temperature Isolation Signal Docket Nos. 50-352 and 50-353 3

2.0 DETAILED DESCRIPTION The changes requested by this License Amendment Request (LAR) are described below for both LGS Units 1 and 2:

1. TS Table 3.3.2-1 is modified by the below line within the Table. The below deletion of Trip Function 1.g is the only modification to the TS Table. A full version of the TS Table is within of this LAR. DELETED will replace the line item.

TRIP FUNCTION ISOLATION SIGNAL (a)

MINIMUM OPERABLE CHANNELS PER TRIP SYSTEM (b)

APPLICABLE OPERATIONAL CONDITION ACTION

1. MAIN STEAM LINE ISOLATION

g. Turbine Enclosure

- Main Steam Line Tunnel Temperature

- High F(f) 16 1, 2, 3 21

2. TS Table 3.3.2-2 is modified by the below line within the Table. The below deletion of Trip Function 1.g is the only modification to the TS Table. A full version of the TS Table is within of this LAR. DELETED will replace the line item.

TRIP FUNCTION TRIP SETPOINT ALLOWABLE VALUE

1. MAIN STEAM LINE ISOLATION

g. Turbine Enclosure - Main Steam Line Tunnel Temperature - High 165°F 175°F

3. TS Table 3.3.2-3 is modified by the below line within the Table. The below deletion of Trip Function 1.g is the only modification to the TS Table. A full version of the TS Table is within of this LAR. DELETED will replace the line item.

TRIP FUNCTION RESPONSE TIME (Seconds)#

1. MAIN STEAM LINE ISOLATION

g. Turbine Enclosure - Main Steam Line Tunnel Temperature - High N.A.

4. TS Table 4.3.2.1-1 is modified by the below line within the Table. The below deletion of Trip Function 1.g is the only modification to the TS Table. A full version of the TS Table is within of this LAR. DELETED will replace the line item.

License Amendment Request Proposed Changes to TE-MSL Tunnel Temperature Isolation Signal Docket Nos. 50-352 and 50-353 4

TRIP FUNCTION CHANNEL CHECK(a)

CHANNEL FUNCTIONAL TEST (a)

CHANNEL CALIBRATION(a)

OPERATIONAL CONDITIONS FOR WHICH SURVEILLANCE REQUIRED

1. MAIN STEAM LINE ISOLATION

g. Turbine Enclosure

- Main Steam Line Tunnel Temperature

- High 1, 2, 3

3.0 TECHNICAL EVALUATION

The TE MSL Tunnel is defined as the area in which the four-safety related main steam lines are routed in the non-safety related main condenser compartment. The steam lines, after entering the TE from the outboard MSIV room, run the length and half the turbine enclosure width until they enter the main turbine stop valves. The steam line arrangement in this plant area is shown in UFSAR Figure 3.6-5.

The TE MSL Tunnel steam leak detection thermocouples are located approximately three feet above the main steam lines. There are thirty-two separate thermocouple locations arranged in eight groups of four sensors that monitor the entire length of the four main steam lines up to the turbine stop valve inlets in this large plant area. The purpose of the steam leak detection thermocouple is to monitor and detect a passive piping pressure boundary leak (not packing, gasket, or other non-pressure boundary leakage) prior to the turbine stop valves.

The purpose of the TE MSL Tunnel Temperature isolation function is to provide timely detection and isolation of small high energy Main Steam line leaks prior to catastrophic failure of the piping while maintaining sufficient margin above normal operating temperatures to avoid spurious isolation. The TE MSL Tunnel Temperature instrumentation is part of the MSIV Group 1 isolation logic and isolates the normally open MSIVs and the normally closed Main Steam line drain valves.

The TE MSL Tunnel Temperature instrumentation and logic is not required to mitigate any design basis event and credit for this isolation instrumentation is not taken in any transient or accident analysis in UFSAR Chapter 15. Bounding analyses are performed for large breaks, such as Main Steam line breaks that solely credit the automatic Main Steam line high flow isolation. The TE MSL Tunnel Temperature isolation and reactor vessel low level and low steam pressure isolations provide a diverse isolation function to the credited Main Steam line high flow isolation. This function does not require an automatic isolation of the MSLs on TE MSL tunnel high temperature in order to assure plant safety. Given the purpose of the function, the consequences of an automatic reactor scram due to closure of the MSIVs is unwarranted.

As an alternative, the proposed TS 3/4.7.9 will ensure that a MSL pressure boundary leak in the TE MSL tunnel will be promptly detected, and appropriate actions will be taken.

License Amendment Request Proposed Changes to TE-MSL Tunnel Temperature Isolation Signal Docket Nos. 50-352 and 50-353 5

The proposed LCO 3.7.9 requires that the TE MSL Tunnel maximum temperature be 175°F.

This value represents the current TS allowable value and is based on detecting a 25-gpm equivalent steam leak during seasonal hot weather conditions and a 35-gpm equivalent steam leak during seasonal cold weather conditions.

The purpose of this preemptive feature is to detect a steam line leak prior to the flow rate corresponding to a critical crack size which will not propagate into a full pipe rupture for the respective system piping. For Limerick the critical crack length for main steam piping, as depicted in UFSAR Figure 5.2-12, is approximately 300 gpm. The corresponding 25 gpm summer and 35 gpm winter threshold is adequate to assure early detection and manual isolation, after condition confirmation, of a main steam line leak within the Turbine Enclosure with a large amount of margin to the critical crack size. This automatic leak before break detection isolation function is not required to satisfy any design basis event (Reference 2).

The Applicability of LCO 3.7.9 is Operational Conditions 1, 2, and 3. In Operational Conditions 1, 2, and 3, a Design Basis Accident (DBA) could result in the release of radioactive material into the TE MSL Tunnel if there is a leak in the MSLs. In Operational Conditions 4 and 5, the probability and consequences of a DBA with fission product release into the TE MSL Tunnel are reduced because of the pressure and temperature limitations in these conditions.

Therefore, maintaining TE MSL tunnel temperature within limits is not required in Operational Conditions 4 or 5. The proposed Applicability is the same as the current Function 1.g.

The proposed Surveillance Requirement (SR) 4.7.9.1 requires verification that the TE MSL tunnel temperature is 175°F. The Frequency is controlled under the SFCP, and the initial frequency will be every 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. As stated in SR 3.0.1, SRs must be met between performances of the Surveillance. If the TE MSL tunnel maximum temperature exceeds 175°F, operators will be alerted to take action.

The TS 3.7.9 Actions apply if the TE MSL tunnel temperature is exceeded. It requires immediate action to determine if there is an MSL pressure boundary leak.

TE MSL tunnel temperature may be elevated due to reasons other than an MSL pressure boundary leak, such as hot weather, reduced TE area chiller capacity, and faulty temperature detectors. Verification will determine whether the elevated temperature is due to an MSL pressure boundary leak or another reason.

If the elevated temperature is determined to not be due to a MSL pressure boundary leak and as long as the TE MSL tunnel temperature exceeds 175°F, the Actions require verification every 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> that no MSL pressure boundary leak exists. The area monitored in the TE MSL Tunnel has elevated radiation levels and adverse environmental conditions. The 12-hour Completion Time balances the small likelihood of a MSL pressure boundary leak occurring since the last verification against the risks of exposing workers to the radiological and environmental conditions in order to perform the verification.

If a MSL pressure boundary leak is detected or if the periodic verification is not performed, the actions require a plant shutdown. The plant must be brought to least Operational Condition 3

License Amendment Request Proposed Changes to TE-MSL Tunnel Temperature Isolation Signal Docket Nos. 50-352 and 50-353 6

(Hot Shutdown) within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and Operational Condition 4 (Cold Shutdown) within the following 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. The proposed times are consistent with the requirements of similar specifications and are reasonable, based on operating experience, to reach the required plant conditions from full power conditions in an orderly manner and without challenging plant systems.

The following TS functions will continue to provide automatic MSL isolation:

Reactor Vessel Water level - Low, Low, Low - Level 1 Main Steam Line Pressure - Low Main Steam Line Flow - High Condenser Vacuum - Low Outboard MSIV Room Temperature - High Removing the automatic isolation function and adding a manual shutdown requirement on high TE MSL tunnel temperature will have no adverse effect on equipment qualification. Once the 175ºF temperature threshold is entered, procedural guidance will trigger an engineering review of qualified SSCs to evaluate the actual condition and any remediating actions.

Although this requested elimination of an automatic isolation function is not risk-informed, CEG has developed risk insights related to the proposed change. The risk analysis was performed to demonstrate with reasonable assurance that eliminating the requirement for automatic MSL isolation on high TE MSL tunnel temperature is within the current risk acceptance guidelines in Regulatory Guide 1.174, "An Approach for Using Probabilistic Risk Assessment in Risk-Informed Decisions on Plant-Specific Changes to the Licensing Basis." The risk analysis was based on the CDF and LERF that results from assuming the TE steam line break high temperature function fails. This analysis does not assume operator action to detect a steam leak and assumes that unisolated breaks of any size result in core damage and large early release. In addition, this analysis does not credit the reduced chance of spurious MSIV actuation from a fire.

This analysis supports the acceptability of the proposed change.

4.0 REGULATORY EVALUATION

4.1 Applicable Regulatory Requirements/Criteria The following applicable regulations and regulatory requirements were reviewed in development of this submittal:

10 CFR 50.36: (1) installed instrumentation that is used to detect, and indicate in the control room, a significant abnormal degradation of the reactor coolant pressure boundary; (2) a process variable, design feature, or operating restriction that is an initial condition of a design basis accident or transient analysis that either assumes the failure of or presents a challenge to the integrity of a fission product barrier; (3) a structure, system, or component that is part of the primary success path and which functions or actuates to mitigate a design basis accident or transient that either assumes the failure of or presents a challenge to the integrity of a fission product barrier; and (4) a structure, system, or component which operating experience or

License Amendment Request Proposed Changes to TE-MSL Tunnel Temperature Isolation Signal Docket Nos. 50-352 and 50-353 7

probabilistic risk assessment (PRA) has shown to be significant to public health and safety. As a result, TS requirements which satisfy any of the criteria in 10 CFR 50.36 must be retained in the TS.

MSL pressure boundary leakage in the Turbine Enclosure is monitored to protect the assumptions of the accident dose analysis. Therefore, the requirement to monitor Turbine Enclosure maximum area temperature is treated as an operating restriction that is an initial condition of a design basis accident or transient analysis that either assumes the failure of, or presents a challenge to, the integrity of a fission product barrier and is maintained in the TS per Criterion 2. Revising the requirement from an automatic isolation to manual detection and shutdown does not affect the ability to satisfy Criterion 2.

• 10 CFR Part 50 Appendix A General Design Criteria (GDC) 30: Components which are part of the Reactor Coolant Pressure Boundary (RCPB) shall be designed, fabricated, erected, and tested to the highest quality standards practical. Means shall be provided for detecting and, to the extent practical, identifying the location of the source of reactor coolant leakage.

Means are provided for detecting reactor coolant leakage. The leak detection system consists of sensors and instruments to detect, annunciate, and, in some cases, isolate the RCPB from potential hazardous leaks before predetermined limits are exceeded.

As described in UFSAR Section 5.2.5, small leaks are detected by temperature and pressure changes, increased frequency of sump pump operation, and measurement of airborne radioactivity in the primary containment atmosphere. In addition to these means of detection, large leaks are detected by flow rates in process lines and changes in reactor water level. The allowable leakage rates are based on the predicted and experimentally determined behavior of cracks in pipes, the ability to make up coolant system leakage, the normally expected background leakage due to equipment design, and the detection capability of the various sensors and instruments.

The total leakage rate limit is established so that, in the absence of normal ac power concurrent with a loss of feedwater supply, makeup capabilities are provided by the RCIC system. While the leak detection system provides protection from small leaks, the ECCS network provides protection for the complete range of discharges from ruptured pipes. Thus, protection is provided for the full spectrum of possible discharges. The RCPB and the leak detection system are designed to meet the requirements of GDC 30.

10 CFR Part 50 Appendix A General Design Criteria (GDC) 54: Piping systems penetrating primary reactor containment shall be provided with leak detection, isolation, and containment having redundancy, reliability, and performance capabilities which reflect the importance to safety of isolating these piping systems.

The LGS design incorporates various and diverse leak detection and containment isolation features to meet the requirements of GDC 54. It is proposed that the TE MSL Tunnel Temperature - High isolation function be removed from the TS for

License Amendment Request Proposed Changes to TE-MSL Tunnel Temperature Isolation Signal Docket Nos. 50-352 and 50-353 8

containment isolation instrumentation. Appropriate automatic isolations for MSIVs are still retained in accordance with GDC 54 by other diverse leakage detection features.

4.2 Precedents By letter dated October 13, 2021, SNC submitted a license amendment request for Edwin I. Hatch Nuclear Plant Unit Nos. 1 and 2 (Hatch) titled, "Request to Eliminate Automatic Main Steam Line Isolation on High Turbine Building Area Temperature" (Agencywide Documents Access and Management System (ADAMS) Accession No. ML21286A595). The amendment was approved on May 20, 2022 (ADAMS Accession No. ML22101A118). The proposed elimination of the LGS TE MSL Tunnel Temperature

- High automatic isolation function is similar to the Hatch precedent.

The Hatch amendment is very similar to the proposed change in that the Hatch instrumentation function, "Turbine Building Area Temperature - High," served the same purpose as the LGS "Turbine Enclosure Main Steam Line Tunnel Temperature,"

function. Both functions actuated the MSIVs on high temperature indications around the MSL. Both functions were intended to automatically shut down the plant on small indications of MSL leakage. In both cases, actuation of the function would cause a complicated scram.

Differences between the Hatch amendment and the proposed change do not affect its use as precedent. Unlike the Hatch TS, the LGS TS are not based on NUREG-1433, "Standard Technical Specifications General Electric [Boiling-Water Reactor] BWR/4 Plants, Volume 1, Specifications," Revision 5.0 (ADAMS Accession No. ML21272A357).

This affects the presentation of the requirements but not the content of the changes.

4.3 No Significant Hazards Consideration In accordance with 10 CFR 50.90, "Application for amendment of license, construction permit, or early site permit," Constellation Energy Generation, LLC (CEG), proposes changes to the Technical Specifications (TS), Appendix A of Renewed Facility Operating License Nos. NPF-39 and NPF-85 for Limerick Generating Station (Limerick), Units 1 and 2, respectively.

The proposed change removes Function 1.g, "Turbine Enclosure - Main Steam Line Tunnel Temperature - High," and inserts the word "Deleted" in the following tables: Table 3.3.2-1 Isolation Actuation Instrumentation, Table 3.3.2-2, "Isolation Actuation Instrumentation Setpoints," Table 3.3.2-3, "Isolation System Instrumentation Response Time," and Table 4.3.2.1-1, Isolation Actuation Instrumentation Surveillance Requirements." Deletion of Function 1.g does not require modification to any Actions or Surveillance Requirements.

License Amendment Request Proposed Changes to TE-MSL Tunnel Temperature Isolation Signal Docket Nos. 50-352 and 50-353 9

The proposed change adds a new Technical Specification 3/4.7.9, "Turbine Enclosure Main Steam Line Tunnel Temperature." The new LCO 3.7.9 requires the TS MSL Tunnel maximum temperature to be 175°F. The specification is applicable in Operational Conditions 1, 2, and 3, the same as existing Function 1.g. SR 4.7.9.1 requires verification that the TE MSL tunnel temperature is 175°F on a frequency controlled by the Surveillance Frequency Control Program (SFCP). The initial frequency will be 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

In the proposed TS, if the TE MSL tunnel maximum temperature exceeds 175°F, the Action requires immediate action to verify that no MSL pressure boundary leak exists, and periodic verification every 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> thereafter. If it cannot be verified that there is no MSL pressure boundary leakage or if the periodic verification is not performed, a plant shutdown is required. The plant must be in Operational Condition 3 (Hot Shutdown) within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and Operational Condition 4 (Cold Shutdown) within the following 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

CEG has evaluated the proposed changes, using the criteria in 10 CFR 50.92, "Issuance of amendment," and has determined that the proposed changes do not involve a significant hazards consideration. The following information is provided to support a finding of no significant hazards consideration.

1.

Do the proposed changes involve a significant increase in the probability or consequences of an accident previously evaluated?

Response: No The proposed changes do not alter any of the previously evaluated accidents in the UFSAR. The proposed changes do not affect any of the initiators of previously evaluated accidents in a manner that would increase the likelihood of the event. The proposed change also eliminates the automatic MSIV isolation function associated with TE MSL Tunnel high temperature from the requirements of the Technical Specifications (TS) and creates TS requirements for TE MSL tunnel temperature monitoring in a new TS 3/4.7.9.

Automatic isolation of the MSIVs on TE MSL tunnel high temperature is not an initiator of any accident previously evaluated. A manual plant shutdown initiated due to MSL leakage in the TE MSL tunnel is not an initiator of any accident previously evaluated. There is no credit taken in any licensing basis analysis for MSIV closure on TE MSL tunnel high temperature, and there are no calculations that credit the subject isolation function as a mitigative feature.

As a result, the likelihood of malfunction of an SSC is not increased. The capability and operation of the mitigation systems are not affected by the proposed changes. Thus, the mitigating systems will continue to be initiated and mitigate the consequences of an accident as assumed in the analysis of accidents previously evaluated.

License Amendment Request Proposed Changes to TE-MSL Tunnel Temperature Isolation Signal Docket Nos. 50-352 and 50-353 10 Therefore, the proposed changes do not involve a significant increase in the probability or consequences of an accident previously evaluated.

2.

Do the proposed changes create the possibility of a new or different kind of accident from any accident previously evaluated?

Response: No The proposed changes will not introduce any new operating modes, safety-related equipment lineups, accident scenarios, system interactions, or failure modes that would create a new or different type of accident. Failure(s) of the system will have the same effect as the present design.

The proposed change also eliminates the automatic MSIV isolation function associated with TE MSL Tunnel high temperature from the requirements of the TS and creates TS requirements for TE MSL tunnel temperature monitoring in a new TS 3/4.7.9. Eliminating the automatic isolation of the MSIVs will not create a new or different kind of accident from those previously evaluated as a Main Steam Line Break has been evaluated. Elimination of the automatic isolation function will not create a new failure mechanism as a plant shutdown continues to be required if an MSL leak is detected.

The proposed change from an automatic shutdown to a manual shutdown will not create any credible new failure mechanisms, malfunctions, or accident initiators not considered in the design and licensing bases. The unlikely failure to manually detect an MSL leak and shutdown the plant and that failure leading to a Main Steam Line Break has already been evaluated and is not a new type of accident.

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

3.

Do the proposed changes involve a significant reduction in a margin of safety?

Response: No The proposed changes do not affect the accident source term, containment isolation, or radiological release assumptions used in evaluating the radiological consequences of any accident previously evaluated and are consistent with safety analysis assumptions and resultant consequences. The proposed changes do not impact reactor operating parameters or the functional requirements of the affected instrumentation systems. These systems will continue to provide the design basis reactor trips and protective system actuations. All design basis events, and the reliance on the reactor trips and protective system actuations will remain unchanged. No controlling numerical values for parameters established in the UFSAR or the license or Safety Limits are affected by the proposed changes.

License Amendment Request Proposed Changes to TE-MSL Tunnel Temperature Isolation Signal Docket Nos. 50-352 and 50-353 11 Therefore, the proposed changes do not involve a significant reduction in a margin of safety.

Based on the above evaluation, CEG concludes that the proposed amendments present no significant hazards consideration under the standards set forth in 10 CFR 50.92, paragraph (c), and accordingly, a finding of "no significant hazards consideration" is justified.

4.4 Conclusions 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 Commission's regulations, and (3) the issuance of the amendments will not be inimical to the common defense and security or the health and safety of the public.

5.0 ENVIRONMENTAL CONSIDERATION

CEG has determined that the proposed changes 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 changes do not involve (i) a significant hazards consideration, (ii) a significant change in the types or 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 changes meet 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 changes.

6.0 REFERENCES

1. Constellation Energy Generation, LLC (CEG) letter to the U.S. Nuclear Regulatory Commission (NRC), License Amendment Request to Revise the Licensing and Design Basis to Incorporate the Replacement of Existing Safety-Related Analog Control Systems with a Single Digital Plant Protection System (PPS), (ADAMS Accession No. ML22269A569, dated September 26, 2022).

2. Letter to Robert G. Byram of Pennsylvania Power and Light Company from the U.S.

Nuclear Regulatory Commission, Susquehanna Steam Electric Station, Units 1 and 2 (TAC NOS. M96327 and M96328). (ADAMS Accession No. ML010160119, dated July 30, 1998).

ATTACHMENT 2 License Amendment Request Limerick Generating Station, Units 1 and 2 Docket Nos. 50-352 and 50-353 License Amendment Request for Proposed Changes to the Technical Specification Isolation Actuation Instrumentation Tables and New Turbine Enclosure Main Steam Line Tunnel Temperature TS 3/4.7.9 Markup of Proposed Technical Specification Pages Unit 1 TS Page 3/4 3-11 3/4 3-18 3/4 3-23 3/4 3-27 3/4 7-XX (new)

Unit 2 TS Page 3/4 3-11 3/4 3-18 3/4 3-23 3/4 3-27 3/4 7-XX (new)

TABLE 3.3.2-1 ISOLATION ACTUATION INSTRUMENTATION MINIMUM APPLICABLE ISOLATION OPERABLE CHANNELS OPERATIONAL TRIP FUNCTION SIGNAL (a)

PER TRIP SYSTEM (b)

CONDITION ACTION 1.

MAIN STEAM LINE ISOLATION a.

Reactor Vessel Water Level 1)

Low, Low-Level 2 B

2 1, 2, 3 21 2)

Low, Low, Low-Level 1 C

2 1, 2, 3 21 b.

DELETED DELETED DELETED DELETED DELETED c.

Main Steam Line Pressure - Low P

2 1

22 d.

Main Steam Line Flow - High E

2/line 1, 2, 3 20 e.

Condenser Vacuum - Low Q

2 1, 2**, 3**

21 f.

Outboard MSIV Room Temperature - High F(f) 2 1, 2, 3 21 g.

Turbine Enclosure - Main Steam Line Tunnel Temperature - High F(f) 16 1, 2, 3 21 h.

Manual Initiation NA 2

1, 2, 3 24 2.

RHR SYSTEM SHUTDOWN COOLING MODE ISOLATION a.

Reactor Vessel Water Level Low - Level 3 A

2 1, 2, 3 23 b.

Reactor Vessel (RHR Cut-In Permissive) Pressure - High V

2 1, 2, 3 23 c.

Manual Initiation NA 1

1, 2, 3 24 LIMERICK - UNIT 1 3/4 3-11 Amendment No. 28, 89, 259, DELETED

TABLE 3.3.2-2 ISOLATION ACTUATION INSTRUMENTATION SETPOINTS TRIP FUNCTION

1.

MAIN STEAM LINE ISOLATION

a.

b.

c.

d.

e.

f.

g.

h.

Reactor Vessel Water Level

1)

Low, Low - Level 2

2)

Low, Low, Low - Level 1 DELETED Main Steam Line Pressure - Low Main Steam Line Flow - High Condenser Vacuum - Low Outboard MSIV Room Temperature

- High Turbine Enclosure - Main Steam Line Tunnel Temperature - High Manual Initiation

2.

RHR SYSTEM SHUTDOWN COOLING MODE ISOLATION

a.

b.

c.

Reactor Vessel Water Level Low - Level 3 Reactor Vessel CRHR Cut-in Permissive) Pressure - High Manual Initiation LIMERICK - UNIT 1 TRIP SETPOINT z - 38 inches*

z - 129 inches*

DELETED z 840 psig

~ 122.l psid 10.5 psia

~ 192°F

~ 165°F N.A.

z 12.5 inches*

~ 75 psig N.A.

3/4 3-18 ALLOWABLE VALUE z - 45 inches z - 136 inches DELETED 2 821 psig

~ 123 psid 210.1 psia/~ 10.9 psia

~ 200°F

~ l 75°F N.A.

z 11.0 inches

~ 95 psig N.A.

Amendment No. ~. &9-, ~. 222 DELETED

TABLE 3.3.2-3 ISOLATION SYSTEM INSTRUMENTATION RESPONSE TIME TRIP FUNCTION

1.

MAIN STEAM LINE ISOLATION

a.

b.

c.

d.

e.

f.

g.

h.

Reactor Vessel Water Level

1)

Low, Low - Level 2

2)

Low, Low, Low-Level 1 DELETED Main Steam Line Pressure - Low Main Steam Line Flow - High Condenser Vacuum - Low Outboard MSIV Room Temperature - High Turbine Enclosure - Main Steam Line Tunnel Temperature - High Manual Initiation

2.

RHR SYSTEM SHUTDOWN COOLING MODE ISOLATION

a.

b.

c.

Reactor Vessel Water Level Low - Level 3 Reactor Vessel (RHR Cut-In Permissive) Pressure - High Manual Initiation

3.

REACTOR WATER CLEANUP SYSTEM ISOLATION

a.

b.

c.

d.

e.

f.

RWCS 6 Flow - High RWCS Area Temperature - High RWCS Area Ventilation 6 Temperature - High SLCS Initiation Reactor Vessel Water Level -

Low, Low - Level 2 Manual Initiation LIMERICK - UNIT 1 3/4 3-23 RESPONSE TIME (Seconds)#

N.A.

.::::1.0###*

DELETED

.::::1.0 ###*

~1.0 ###*

N.A.

N.A.

N.A.

N.A.

N.A.

N.A.

N.A.

N.A. ##

N.A.

N.A.

N.A.

N.A.

N.A.

Amendment No. ~.gg.~, 214 DELETED

TABLE 4.3.2.1-1 ISOLATION ACTUATION INSTRUMENTATION SURVEILLANCE REOTIIREMENTS CHANNEL TRIP FUNCTION CHECK(a)

CHANNEL FUNCTIONAL TEST(a)

CHANNEL CALIBRATION(a)

OPERATIONAL CONDITIONS FOR WHICH SURVEILLANCE REOUIRED I

1.

MAIN STEAM LINE ISOLATION

a.

Reactor Vessel Water Level

1) Low,

Low, Level 2

2) Low,

Low, Low - Level 1 1, 2, 3 1, 2, 3

b.

DELETED

c.

Main Steam Line Pressure -

Low

d.

Main Steam Line Flow - High 1

1, 2, 3

e.

. Condenser Vacuum - Low

f.

Outboard MSIV Room Temperature - High

g.

Turbine Enclosure - Main Steam Line Tunnel Temperature - High

h.

Manual Initiation

2.

RHR SYSTEM SHUTDOWN COOLING MODE ISOLATION

a.

Reactor Vessel Water Level##

Low - Level 3

b.

Reactor Vessel (RHR Cut-In Permissive) Pressure - High

c.

Manual Initiation LIMERICK - UNIT 1 1, 2**, 3**

1, 2, 3 1, 2, 3

1. 2, 3

N.A.

N.A.

I 1, 2, 3

1, 2, 3 1, 2, 3 II N.A.

N.A.

I 3/4 3-27 Amendment No.

8, 6 186 DELETED

3/4.7 PLANT SYSTEMS 3/4.7.9 TURBINE ENCLOSURE MAIN STEAM LINE TUNNEL TEMPERATURE LIMITING CONDITION FOR OPERATION 3.7.9 The Turbine Enclosure Main Steam Line Tunnel temperature shall be 175.

APPLICABILITY: OPERATIONAL CONDITIONS 1, 2, and 3 ACTION:

With the Turbine Enclosure (TE) Main Steam Line Tunnel temperature >175, immediately and at least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> thereafter verify there is no leakage from the Main Steam Line pressure boundary within the TE Main Steam Line Tunnel.

Otherwise, be in HOT SHUTDOWN within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and COLD SHUTDOWN within the following 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

SURVEILLANCE REQUIREMENT 4.7.9.1 The Turbine Enclosure Main Steam Line Tunnel temperature shall be determined to be 175 in accordance with the Surveillance Frequency Control Program.

LIMERICK - UNIT 1 3/4 7-XX Amendment No.

TS 3.7.9 Entire page is new

TABLE 3.3.2-1 ISOLATION ACTUATION INSTRUMENTATION MINIMUM APPLICABLE ISOLATION OPERABLE CHANNELS OPERATIONAL TRIP FUNCTION SIGNAL (a)

PER TRIP SYSTEM (b) CONDITION ACTION 1.

MAIN STEAM LINE ISOLATION a.

Reactor Vessel Water Level 1)

Low, Low-Level 2 B

2 1, 2, 3 21 2)

Low, Low, Low-Level 1 C

2 1, 2, 3 21 b.

DELETED DELETED DELETED DELETED DELETED c.

Main Steam Line Pressure - Low P

2 1

22 d.

Main Steam Line Flow - High E

2/line 1, 2, 3 20 e.

Condenser Vacuum - Low Q

2 1, 2**, 3**

21 f.

Outboard MSIV Room Temperature - High F(f) 2 1, 2, 3 21 g.

Turbine Enclosure - Main Steam Line Tunnel Temperature - High F(f) 16 1, 2, 3 21 h.

Manual Initiation NA 2

1, 2, 3 24 2.

RHR SYSTEM SHUTDOWN COOLING MODE ISOLATION a.

Reactor Vessel Water Level Low - Level 3 A

2 1, 2, 3 23 b.

Reactor Vessel (RHR Cut-In Permissive) Pressure - High V

2 1, 2, 3 23 c.

Manual Initiation NA 1

1, 2, 3 24 LIMERICK - UNIT 2 3/4 3-11 Amendment No. 52, 221 DELETED

TABLE 3.3.2-2 ISOLATION ACTUATION INSTRUMENTATION SETPOINTS TRIP FUN CTI ON

1.

MAIN STEAM LINE ISOLATION

a.

Reactor Vessel Water Level

1)

Low, Low - Level 2

2)

Low, Low, Low - Level 1

b.

DELETED

c.

Main Steam Line Pressure - Low

d.

Main Steam Line Flow - High

e.

Condenser Vacuum - Low

f.

Outboard MSIV Room Temperature - High

g.

Turbine Enclosure - Main Steam Line Tunnel Temperature - High

h.

Manual Initiation

2.

RHR SYSTEM SHUTDOWN COOLING MODE ISOLATION

a.

Reactor Vessel Water Level Low - Level 3

b.

Reactor Vessel (RHR Cut-in Permissive) Pressure - High

c.

Manual Initiation LIMERICK - UNIT 2 TRIP SETPOINT

.::=:

- 38 inches*

.::=:

- 129 inches*

DELETED

.::: 840 psig

.:::: 122.1 psid 10.5 psia

.:S 192°F

.::; 165°F N.A.

.::=: 12.5 inches*

.:::: 75 psig N.A.

3/4 3-18 ALLOWABLE VALUE

.::=: - 45 inches

.::=:

- 136 inches DELETED

.::: 821 psig

.:::: 123 psid

.:::10.1 psia/~ 10.9 psia

.:S 200°F

.:S 175°F N.A.

.::=: 11.0 inches

.:::: 95 psig N.A.

Amendment No..e.+/-, ~. 183 DELETED

TABLE 3.3.2-3 ISOLATION SYSTEM INSTRUMENTATION RESPONSE TIME TRIP FUNCTION

1.

MAIN STEAM LINE ISOLATION

a.

b.

c.

d.

e.

f.

g.

h.

Reactor Vessel Water Level

1)

Low, Low - Level 2

2)

Low, Low, Low-Level 1 DELETED Main Steam Line Pressure - Low Main Steam Line Flow - High Condenser Vacuum - Low Outboard MSIV Room Temperature - High Turbine Enclosure - Main Steam Line Tunnel Temperature - High Manual Initiation

2.

RHR SYSTEM SHUTDOWN COOLING MODE ISOLATION

a.

b.

c.

Reactor Vessel Water Level Low - Level 3 Reactor Vessel (RHR Cut-In Permissive) Pressure - High Manual Initiation

3.

REACTOR WATER CLEANUP SYSTEM ISOLATION

a.

b.

c.

d.

e.

f.

RWCS 6 Flow - High RWCS Area Temperature - High RWCS Area Ventilation 6 Temperature - High SLCS Initiation Reactor Vessel Water Level -

Low, Low - Level 2 Manual Initiation LIMERICK - UNIT 2 3/4 3-23 RESPONSE TIME (Seconds)#

N.A.

Sl.O ###*

DELETED

Sl. 0 ###*

~1. 0 ###*

N.A.

N.A.

N.A.

N.A.

N.A.

N.A.

N.A.

N.A. ##

N.A.

N.A.

N.A.

N.A.

N.A.

Amendment No.~.~. 175 DELETED

TABLE 4.3.2.1-1 ISOLATION ACTIIATION INSTRUIMENTATTON SIIRVETI I ANCE RFOIiTPFMFNTS isnLAMN ACTUATION INSTRUMENTATION SURVEILLANCE REQUIREMENTS CHANNEL TRIP FUNCTION CHECK (a)

CHANNEL FUNCTIONAL TEST (a)

CHANNEL CALIBRATION(a)

OPERATIONAL CONDITIONS FOR WHICH SURVEILLANCE REOUIRED I

1.

MAIN STEAM LINE ISOLATION

a.

Reactor Vessel Water Level

1)

Low, Low, Level 2

2)

Low, Low, Low - Level 1

b.

DELETED

c.

Main Steam Line Pressure - Low

d.

Main Steam Line Flow - High

e.

Condenser Vacuum -

Low 1, 2, 3 1, 2, 3 DELETED 1

1, 2, 3 1, 2**, 3**

f.

Outboard MSIV Room Temperature-High

g.

Turbine Enclosure Main Steam Line Tunnel Temperature

- High

h.

Manual Initiation

2.

RHR SYSTEM SHUTDOWN COOLING MODE ISOLATION

a.

Reactor Vessel Water Level##

Low - Level 3

b.

Reactor Vessel (RHR Cut-In Permissive) Pressure - High

c.

Manual Initiation 1, 2, 3 1, 2, 3

1. 2, 3 N.A.

N.A.

1, 2, 3 1, 2, 3 1, 2, 3

I I

N.A.

N.A.

LIMERICK - UNIT 2 3/4 3-27 Amendment No.

4-7-, 3,,147 DELETED

LIMERICK - UNIT 2 3/4 7-XX Amendment No.

TS 3.7.9 3/4.7 PLANT SYSTEMS 3/4.7.9 TURBINE ENCLOSURE MAIN STEAM LINE TUNNEL TEMPERATURE LIMITING CONDITION FOR OPERATION 3.7.9 The Turbine Enclosure Main Steam Line Tunnel temperature shall be 175.

APPLICABILITY: OPERATIONAL CONDITIONS 1, 2, and 3 ACTION:

With the Turbine Enclosure (TE) Main Steam Line Tunnel temperature >175, immediately and at least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> thereafter verify there is no leakage from the Main Steam Line pressure boundary within the TE Main Steam Line Tunnel.

Otherwise, be in HOT SHUTDOWN within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and COLD SHUTDOWN within the following 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

SURVEILLANCE REQUIREMENT 4.7.9.1 The Turbine Enclosure Main Steam Line Tunnel temperature shall be determined to be 175 in accordance with the Surveillance Frequency Control Program.

Entire page is new

ATTACHMENT 3 License Amendment Request Limerick Generating Station, Units 1 and 2 Docket Nos. 50-352 and 50-353 License Amendment Request for Proposed Changes to the Technical Specification Isolation Actuation Instrumentation Tables and New Turbine Enclosure Main Steam Line Tunnel Temperature TS 3/4.7.9 Markup of Proposed Technical Specification Bases Pages (For Information Only)

Unit 1 TS Page B 3/4 7-5 Unit 2 TS Page B 3/4 7-5

3/4.7.9 TURBINE ENCLOSURE MAIN STEAM LINE TUNNEL TEMPERATURE Should a temperature greater than the limit be detected, operators will determine if there is a leak from the Main Steam Line pressure boundary. Evidence of a Main Steam Line leak includes, but is not limited to:

- An unexpected, sudden rise in tunnel temperature,

- An unexpected increase in radiation monitor readings,

- An unexpected rise in TE sump levels,

- An unexpected decrease in plant electrical output, or

- Visual and sound indications.

If a Main Steam Line pressure boundary leak is detected, a plant shutdown is required.

Pressure boundary leakage includes ASME SSC(s). Leakage past gaskets, packing, and seals is not pressure boundary leakage.

3/4.7.9 TURBINE ENCLOSURE MAIN STEAM LINE TUNNEL TEMPERATURE Should a temperature greater than the limit be detected, operators will determine if there is a leak from the Main Steam Line pressure boundary. Evidence of a Main Steam Line leak includes, but is not limited to:

- An unexpected, sudden rise in tunnel temperature,

- An unexpected increase in radiation monitor readings,

- An unexpected rise in TE sump levels,

- An unexpected decrease in plant electrical output, or

- Visual and sound indications.

If a Main Steam Line pressure boundary leak is detected, a plant shutdown is required.

Pressure boundary leakage includes ASME SSC(s). Leakage past gaskets, packing, and seals is not pressure boundary leakage.