Text

Application to Revise Technical Specifications to Adopt TSTF-582, Revision 0 Reactor Pressure Vessel Water Inventory Control (RPV WIC) Enhancements
	ML20247J372
Person / Time
Site:	Limerick
Issue date:	09/03/2020
From:	David Helker; Exelon Generation Co
To:	; Document Control Desk, Office of Nuclear Reactor Regulation
References
	Download: ML20247J372 (48)
	v • d • e

200 Exelon Way Kennett Square, PA 19348 www.exeloncorp.com 10 CFR 50.90 September 3, 2020 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission 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:

Application to Revise Technical Specifications to Adopt TSTF-582, Revision 0 "Reactor Pressure Vessel Water Inventory Control (RPV WIC) Enhancements" Pursuant to 10 CFR 50.90, Application for amendment of license or construction permit, or early site permit, Exelon Generation Company, LLC (Exelon), proposes changes to the Technical Specifications (TS), Appendix A of Renewed Facility Operating License Nos. NPF-39 and NPF-85 for Limerick Generating Station (LGS), Units 1 and 2, respectively.

Exelon requests adoption of TSTF-582, Revision 0, "Reactor Pressure Vessel Water Inventory Control (RPV WIC) Enhancements." The TS related to RPV WIC are being revised to incorporate operating experience and to correct errors and omissions in TSTF-542, Revision 2, "Reactor Pressure Vessel Water Inventory Control."

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

The proposed changes have been reviewed and approved by the sites Plant Operations Review Committee in accordance with the requirements of the Exelon Quality Assurance Program.

Exelon requests that the amendment requests be reviewed under the Consolidated Line Item Improvement Process (CLIIP).

Exelon requests approval of the proposed amendments by March 5, 2021 in support of the refueling outage scheduled to begin on April 26, 2021. Once approved, the amendments shall be implemented within 60 days.

There are no regulatory commitments contained in this submittal.

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

License Amendment Request Adopt TSTF-582 RPV WIC Enhancements Docket Nos. 50-352 and 50-353 September 3, 2020 Page 2 Should you have any questions concerning this letter, please contact Glenn Stewart at 610-765-5529 or Steve Flickinger at 267-533-1437.

I declare under penalty of perjury that the foregoing is true and correct. Executed on the 3rd day of September 2020.

Respectfully, David P. Helker Sr. Manager - Licensing Exelon Generation Company, LLC

Enclosure:

Description and Assessment Attachments: 1. Proposed Technical Specification Changes (Mark-Up)

2. Proposed Technical Specification Bases Changes (Mark-Up) - For Information Only cc: USNRC Region I, Regional Administrator w/ attachments USNRC Project Manager, LGS "

USNRC Senior Resident Inspector, LGS "

Director, Bureau of Radiation Protection - Pennsylvania Department of Environmental Protection "

ENCLOSURE License Amendment Request Limerick Generating Station, Units 1 and 2 Docket Nos. 50-352 and 50-353 Application to Revise Technical Specifications to Adopt TSTF 582, "Reactor Pressure Vessel Water Inventory Control (RPV WIC) Enhancements" Description and Assessment

License Amendment Request Enclosure Adopt TSTF-582 RPV WIC Enhancements Page 1 of 5 Docket Nos. 50-352 and 50-353 Description and Assessment

1.0 DESCRIPTION

Pursuant to 10 CFR 50.90, Application for amendment of license or construction permit, or early site permit, Exelon Generation Company, LLC (Exelon), proposes changes to the Technical Specifications (TSs), Appendix A of Renewed Facility Operating License Nos. NPF-39 and NPF-85 for Limerick Generating Station (LGS), Units 1 and 2, respectively.

Exelon requests adoption of TSTF-582, Revision 0, "Reactor Pressure Vessel Water Inventory Control (RPV WIC) Enhancements" (Reference 1). The TSs related to RPV WIC are revised to incorporate operating experience and to correct errors and omissions in TSTF-542, Revision 2, "Reactor Pressure Vessel Water Inventory Control" (Reference 2).

2.0 ASSESSMENT 2.1 Applicability of Safety Evaluation Exelon has reviewed the NRC safety evaluation for TSTF-582 provided to the Technical Specifications Task Force in a letter dated August 13, 2020 (Reference 3). This review included a review of the NRC staffs evaluation, as well as the information provided in TSTF-582. Exelon has concluded that the justifications presented in TSTF-582 and the safety evaluation prepared by the NRC staff are applicable to LGS, Units 1 and 2 and justify this amendment for incorporation of the changes to the LGS TS.

Exelon verifies that the required ECCS injection/spray subsystem can be aligned and the pump started using relatively simple evolutions involving the manipulation of a small number of components. These actions can be performed in a short time (less than the minimum Drain Time of 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months ) from the control room following plant procedures.

2.2 Optional Changes and Variations Exelon is proposing the following variations from the TS changes described in TSTF-582 or the applicable parts of the NRC staffs safety evaluation.

LGS TS are based on the previous version of the NRC's Standard TS (NUREG-0123, Revision

2) (Reference 4) and, therefore, the wording and format varies slightly from the NRC Improved Standard Technical Specifications (NUREG-1433) shown in TSTF-582, Revision 0, and the applicable parts of the NRC's safety evaluation. These differences are administrative and do not affect the applicability of TSTF-582 to the LGS TS.

Note also that LGS uses different numbering and titles than the improved Standard Technical Specifications (STS) in several instances. These differences are administrative and do not affect the applicability of TSTF-582 to the LGS TS.

TS Surveillance Requirement (SR) 4.5.2.4 is revised to correct an administrative error when this SR was modified as part of the TSTF-542 amendment, i.e., there was no frequency specified in the SR. SR 4.5.2.4 states " Verify, for the required ECCS injection/spray subsystem, locations susceptible to gas accumulation are sufficiently filled with water." LGS has a Surveillance Frequency Control Program (SFCP) and all surveillances under TS 3.5.2 are under the SFCP

License Amendment Request Enclosure Adopt TSTF-582 RPV WIC Enhancements Page 2 of 5 Docket Nos. 50-352 and 50-353 Description and Assessment as noted in the other individual TS 3.5.2 surveillances. Therefore, in order to correct this error, the phrase "in accordance with the Surveillance Frequency Control Program" is proposed to be added to the end of the existing SR 4.5.2.4, which will state " Verify, for the required ECCS injection/spray subsystem, locations susceptible to gas accumulation are sufficiently filled with water in accordance with the Surveillance Frequency Control Program." This change is administrative and does not affect the applicability of TSTF-582 to the LGS TS.

The model application provided in TSTF-582 includes an attachment for typed, camera-ready (revised) TS pages reflecting the proposed changes. LGS is not including such an attachment due to the number of TS pages included in this submittal that have the potential to be affected by other unrelated license amendment requests and the straightforward nature of the proposed changes. Providing only mark-ups of the proposed TS changes satisfies the requirements of 10 CFR 50.90, "Application for amendment of license, construction permit, or early site permit," in that the mark-ups fully describe the changes desired. This is an administrative deviation from TSTF-582 with no impact on the NRC's model safety evaluation published on August 13, 2020.

As a result of this deviation, the contents and numbering of the attachments for this amendment request differ from the attachments specified in the model application in TSTF-582.

3.0 REGULATORY ANALYSIS

3.1 No Significant Hazards Consideration Analysis Exelon Generation Company, LLC (Exelon), proposes changes to the Technical Specifications (TS), Appendix A of Renewed Facility Operating License Nos. NPF-39 and NPF-85 for Limerick Generating Station (LGS), Units 1 and 2, respectively.

Exelon requests adoption of TSTF-582, Revision 0, "Reactor Pressure Vessel Water Inventory Control (RPV WIC) Enhancements. The TSs related to RPV WIC are revised to incorporate operating experience and to correct errors and omissions that were incorporated into the plant TS when adopting TSTF-542, Revision 2, "Reactor Pressure Vessel Water Inventory Control."

TSTF-582 includes the following changes to the TS:

1. The TS are revised to eliminate the requirement for a manual ECCS initiation signal to start the required ECCS injection/spray subsystem, and to instead rely on manual valve alignment and pump start.

2. The Drain Time definition is revised to move the examples of common mode failure mechanisms to the Bases and seismic events are no longer considered a common mode failure mechanism.

3. The Drain Time definition exception from considering the Drain Time for penetration flow paths isolated with manual or automatic valves that are "locked, sealed, or otherwise secured" is revised to apply the exception for manual or automatic valves that are "closed and administratively controlled."

4. The TSs are revised to permit placing an inoperable isolation channel in trip as an alternative to declaring the associated penetration flow path incapable of automatic isolation.

5. A Surveillance Requirement (SR) that requires operating the required Emergency Core Cooling System (ECCS) injection/spray subsystem for at least 10 minutes

License Amendment Request Enclosure Adopt TSTF-582 RPV WIC Enhancements Page 3 of 5 Docket Nos. 50-352 and 50-353 Description and Assessment through the recirculation line, is modified to permit crediting normal operation of the system to satisfy the SR and to permit operation through the test return line.

6. SR 4.5.2.4 is enhanced to direct the User to the location of the SR frequency within the SFCP.

Exelon has evaluated if a significant hazards consideration is involved with the proposed amendments by focusing on the three standards set forth in 10 CFR 50.92, "Issuance of amendment," as discussed below:

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

Response: No The proposed changes incorporate operating experience and correct errors and omissions that were incorporated into the plant TS when adopting TSTF-542, Revision 2, "Reactor Pressure Vessel Water Inventory Control." Draining of RPV water inventory in Operational Condition (OPCON) 4 (i.e., cold shutdown) and OPCON 5 (i.e., refueling) is not an accident previously evaluated and, therefore, revising the existing TS controls to prevent or mitigate such an event has no effect on any accident previously evaluated.

RPV water inventory control in OPCON 4 or OPCON 5 is not an initiator of any accident previously evaluated. The existing and revised TS controls are not mitigating actions assumed in any accident previously evaluated.

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 incorporate operating experience and correct errors and omissions that were incorporated into the plant TSs when adopting TSTF-542, Revision 2, "Reactor Pressure Vessel Water Inventory Control." The event of concern under the current requirements and the proposed change is an unexpected draining event. The TSs have contained requirements related to an unexpected draining event during shutdown for over 40 years and this event does not appear as an analyzed event in the Updated Final Safety Analysis Report (UFSAR) for any plant or in the NRC's Standard Review Plan (NUREG-0800). Therefore, an unexpected draining event is not a new or different kind of accident not considered in the design and licensing bases that would have been considered a design basis accident in the UFSAR had it been previously identified.

None of the equipment affected by the proposed changes has a design function described in the UFSAR to mitigate an unexpected draining event in OPCONs 4 or 5, although the equipment may be used for that purpose. Therefore, the proposed

License Amendment Request Enclosure Adopt TSTF-582 RPV WIC Enhancements Page 4 of 5 Docket Nos. 50-352 and 50-353 Description and Assessment changes will not change the design function of the affected equipment. The proposed changes will affect the operation of certain equipment, such as the manual initiation function and related instrumentation to permit initiation of the required ECCS injection/spray subsystem, and the control of valves credited for preventing a draining event. However, these changes provide adequate protection to prevent or mitigate an unexpected draining event and do not create the possibility of a new or different kind of accident due to credible new failure mechanisms, malfunctions, or accident initiators not considered in the design and licensing bases.

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 incorporate operating experience and correct errors and omissions that were incorporated into the plant TSs when adopting TSTF-542, Revision 2, "Reactor Pressure Vessel Water Inventory Control."

The safety basis for the RPV WIC requirements is to protect Safety Limit 2.1.4. The proposed changes do not affect any specific values that define a safety margin as established in the licensing basis. The proposed changes do not affect a design basis or safety limit, or any controlling value for a parameter established in the UFSAR or the license. Therefore, the proposed changes do not significantly reduce the margin of safety.

Therefore, the proposed changes do not involve a significant reduction in a margin of safety.

Based on the above, Exelon concludes that the proposed changes present 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 EVALUATION 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. The proposed changes do not involve (i) a significant hazards consideration, (ii) a significant change in the types or significant increase in the

License Amendment Request Enclosure Adopt TSTF-582 RPV WIC Enhancements Page 5 of 5 Docket Nos. 50-352 and 50-353 Description and Assessment 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.

5.0 REFERENCES

1. TSTF-582, Revision 0, " Reactor Pressure Vessel Water Inventory Control (RPV WIC)

Enhancements," dated August 28, 2019 ADAMS Accession No. ML19240A260.

2. TSTF-542, Revision 2, "Reactor Pressure Vessel Water Inventory Control," dated March 14, 2016. ADAMS Accession No. ML16074A448.

3. Final Safety Evaluation of Technical Specifications Task Force Traveler TSTF-582, Revision 0, "Reactor Pressure Vessel Water Inventory Control (RPV WIC)

Enhancements," dated August 13, 2020. ADAMS Accession No. ML20219A317.

4. NUREG-0123, Revision 2, "Standard Technical Specifications General Electric Boiling Water Reactors (GE-STS)," dated August 1979.

ATTACHMENT 1 License Amendment Request Limerick Generating Station, Units 1 and 2 Docket Nos. 50-352 and 50-353 Application to Revise Technical Specifications to Adopt TSTF-582, "Reactor Pressure Vessel Water Inventory Control (RPV WIC) Enhancements" Proposed Technical Specifications Markup Pages Unit 1 and Unit 2 TS Pages 1-2 (no changes, provided for Information Only) 1-2a 3/4 3-41a 3/4 3-41b 3/4 3-41c 3/4 3-41d 3/4 3-41e 3/4 5-6a 3/4 5-7

DEFINITIONS CORE ALTERATION 1.7 CORE ALTERATION shall be the movement of any fuel, sources, or reactivity control components within the reactor vessel with the vessel head removed and fuel in the vessel. The following exceptions are not considered to be CORE ALTERATIONS:

a) Movement of source range monitors, local power range monitors, intermediate range monitors, traversing incore probes, or special moveable detectors (including undervessel replacement); and b) Control rod movement, provided there are no fuel assemblies in the associated core cell.

Suspension of CORE ALTERATIONS shall not preclude completion of movement of a component to a safe position.

CORE OPERATING LIMITS REPORT 1.7a The CORE OPERATING LIMITS REPORT (COLR) is the unit-specific document that provides the core operating limits for the current operating reload cycle. These cycle-specific core operating limits shall be determined for each reload cycle in accordance with Specifications 6.9.1.9 thru 6.9.1.12. Plant operation within these limits is addressed in individual specifications.

CRITICAL POWER RATIO 1.8 The CRITICAL POWER RATIO (CPR) shall be the ratio of that power in the assembly which is calculated by application of the (GEXL) correlation to cause some point in the assembly to experience boiling transition, Information Only divided by the actual assembly operating power.

DOSE EQUIVALENT I-131 1.9 DOSE EQUIVALENT I-131 shall be that concentration of I-131, microcuries per gram, which alone would produce the same inhalation committed effective dose equivalent (CEDE) as the quantity and isotopic mixture of I-131, I-132, I-133, I-134, and I-135 actually present. The inhalation committed effective dose equivalent (CEDE) conversion factors used for this calculation shall be those listed in Table 2.1 of Federal Guidelines Report 11, Limiting Values of Radionuclide Intake and Air Concentration and Dose Conversion Factors for Inhalation, Submersion, and Ingestion, ORNL, 1989, as described in Regulatory Guide 1.183. The factors in the column headed effective yield doses corresponding to the CEDE.

DOWNSCALE TRIP SETPOINT (DTSP) 1.9a The downscale trip setpoint associated with the Rod Block Monitor (RBM) rod block trip setting.

DRAIN TIME 1.9b The DRAIN TIME is the time it would take for the water inventory in and above the Reactor Pressure Vessel (RPV) to drain to the top of the active fuel (TAF) seated in the RPV assuming:

a) The water inventory above the TAF is divided by the limiting drain rate; b) The limiting drain rate is the larger of the drain rate through a single penetration flow path with the highest flow rate, or the sum of the drain rates through multiple penetration flow paths LIMERICK - UNIT 1 1-2 Amendment No. 37, 66, 87, 174, 185, 227

DEFINITIONS DRAIN TIME (Continued) susceptible to a common mode failure (e.g., seismic event, loss of normal power, single human error), for all penetration flow paths below the TAF except:

1. Penetration flow paths connected to an intact closed system, or isolated by manual or automatic valves that are closed and administratively controlled locked, sealed, or otherwise secured in the closed position, blank flanges, or other devices that prevent flow of reactor coolant through the penetration flow paths;

2. Penetration flow paths capable of being isolated by valves that will close automatically without offsite power prior to the RPV water level being equal to the TAF when actuated by RPV water level isolation instrumentation; or

3. Penetration flow paths with isolation devices that can be closed prior to the RPV water level being equal to the TAF by a dedicated operator trained in the task, who is in continuous communication with the control room, is stationed at the controls, and is capable of closing the penetration flow path isolation device without offsite power.

c) The penetration flow paths required to be evaluated per paragraph b) are assumed to open instantaneously and are not subsequently isolated, and no water is assumed to be subsequently added to the RPV water inventory; d) No additional draining events occur; and e) Realistic cross-sectional areas and drain rates are used.

A bounding DRAIN TIME may be used in lieu of a calculated value.

1.10 (Deleted)

EMERGENCY CORE COOLING SYSTEM (ECCS) RESPONSE TIME 1.11 The EMERGENCY CORE COOLING SYSTEM (ECCS) RESPONSE TIME shall be that time interval from when the monitored parameter exceeds its ECCS actuation set-point at the channel sensor until the ECCS equipment is capable of performing its safety function, i.e., the valves travel to their required positions, pump discharge pressures reach their required values, etc. Times shall include diesel generator starting and sequence loading delays where applicable. The response time may be measured by any series of sequential, overlapping or total steps such that the entire response time is measured.

LIMERICK - UNIT 1 1-2a Amendment No. 37, 66, 87, 174, 185, 227

INSTRUMENTATION 3/4.3.3.A REACTOR PRESSURE VESSEL (RPV) WATER INVENTORY CONTROL (WIC)

INSTRUMENTATION LIMITING CONDITION FOR OPERATION 3.3.3.A The RPV Water Inventory Control (WIC) instrumentation channels shown in Table 3.3.3.A-1 shall be OPERABLE.

APPLICABILITY: As shown in Table 3.3.3.A-1 ACTION:

a. With one or more channels inoperable in a trip system, take the ACTION referenced in Table 3.3.3.A-1 for the trip system.

SURVEILLANCE REQUIREMENTS 4.3.3.1.A Each RPV Water Inventory Control (WIC) instrumentation channel shall be demonstrated OPERABLE by performance of the CHANNEL CHECK and, CHANNEL FUNCTIONAL TEST and LOGIC SYSTEM FUNCTIONAL TEST as shown in Table 4.3.3.A-1 and at the frequencies specified in the Surveillance Frequency Control Program unless otherwise noted in Table 4.3.3.A-1.

LIMERICK - UNIT 1 3/4 3-41a Amendment No. 227

TABLE 3.3.3.A-1 RPV WATER INVENTORY CONTROL (WIC) INSTRUMENTATION MINIMUM OPERABLE Insert: DELETED CHANNELS PER APPLICABLE TRIP OPERATIONAL TRIP FUNCTION FUNCTION CONDITIONS ACTION

1. CORE SPRAY SYSTEM

a. Reactor Vessel Pressure - Low (Permissive) 6(a) 4, 5 39

b. Manual Initiation 2(a)(c) 4, 5 40

2. LOW PRESSURE COOLANT INJECTION MODE OF RHR SYSTEM

a. Injection Valve Differential Pressure - Low (Permissive) 1/valve(a) 4, 5 39

b. Manual Initiation 1(a) 4, 5 40

3. RHR SYSTEM SHUTDOWN COOLING MODE ISOLATION

a. Reactor Vessel Water Level -

Low - Level 3 2 in one (b) 38 trip system

4. REACTOR WATER CLEANUP SYSTEM ISOLATION

a. Reactor Vessel Water Level -

Low, Low - Level 2 2 in one (b) 38 trip system (a) Associated with an ECCS subsystem required to be OPERABLE by LCO 3.5.2, "REACTOR PRESSURE VESSEL (RPV) WATER INVENTORY CONTROL (WIC)."

(b) When automatic isolation of the associated penetration flow path(s) is credited in calculating DRAIN TIME.

(c) The manual initiation push buttons start the respective core spray pump and diesel generator. The "A" and "B" logic manual push buttons also actuate an initiation permissive in the injection valve opening logic.

Insert: DELETED LIMERICK - UNIT 1 3/4 3-41b Amendment No. 227

TABLE 3.3.3.A-1 (Continued)

RPV WATER INVENTORY CONTROL (WIC) INSTRUMENTATION ACTION STATEMENTS ACTION 38 - Immediately initiate action to place the channel in trip, or Ddeclare the associated trip system for the penetration flow path(s) incapable of automatic isolation and initiate action to calculate DRAIN TIME.

ACTION 39 - Within 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months , place channel in trip. Otherwise, declare associated low pressure ECCS injection/spray subsystem inoperable.

ACTION 40 - Within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months , restore channel to OPERABLE status. Otherwise, declare associated low pressure ECCS injection/spray subsystem inoperable.

Insert: DELETED LIMERICK - UNIT 1 3/4 3-41c Amendment No. 227

TABLE 3.3.3.A-2 RPV WATER INVENTORY CONTROL (WIC) INSTRUMENTATION SETPOINTS ALLOWABLE TRIP FUNCTION Insert: DELETED VALUE

1. CORE SPRAY SYSTEM

a. Reactor Vessel Pressure - Low (Permissive) > 435 psig

b. Manual Initiation (decreasing) N.A.

2. LOW PRESSURE COOLANT INJECTION MODE OF RHR SYSTEM

a. Injection Valve Differential Pressure - Low (Permissive) < 84 psid

b. Manual Initiation N.A.

3. RHR SYSTEM SHUTDOWN COOLING MODE ISOLATION

a. Reactor Vessel Water Level -

Low - Level 3 11.0 inches

4. REACTOR WATER CLEANUP SYSTEM ISOLATION

a. Reactor Vessel Water Level -

Low, Low - Level 2 -45 inches LIMERICK - UNIT 1 3/4 3-41d Amendment No. 227

TABLE 4.3.3.A-1 RPV WATER INVENTORY CONTROL (WIC) INSTRUMENTATION SURVEILLANCE REQUIREMENTS CHANNEL LOGIC SYSTEM OPERATIONAL CHANNEL FUNCTIONAL FUNCTIONAL CONDITIONS FOR WHICH TRIP FUNCTION CHECK(a) TEST(a) TEST(a) SURVEILLANCE REQUIRED Insert: DELETED

1. CORE SPRAY SYSTEM

a. Reactor Vessel Pressure - Low (Permissive) N.A. 4, 5

b. Manual Initiation N.A. N.A. 4, 5

2. LOW PRESSURE COOLANT INJECTION MODE OF RHR SYSTEM

a. Injection Valve Differential Pressure - Low (Permissive) N.A. 4, 5

b. Manual Initiation N.A. N.A. 4, 5

3. RHR SYSTEM SHUTDOWN COOLING MODE ISOLATION

a. Reactor Vessel Water Level -

Low - Level 3 N.A. (b)

4. REACTOR WATER CLEANUP SYSTEM ISOLATION

a. Reactor Vessel Water Level -

Low, Low - Level 2 N.A. (b)

(a) Frequencies are specified in the Surveillance Frequency Control Program unless otherwise noted in the table.

(b) When automatic isolation of the associated penetration flow path(s) is credited in calculating DRAIN TIME.

LIMERICK - UNIT 1 3/4 3-41e Amendment No. 227

EMERGENCY CORE COOLING SYSTEMS LIMITING CONDITION FOR OPERATION (Continued)

ACTION:

c. With DRAIN TIME less than 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months and greater than or equal to 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months , within 4 hour4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months s:

1. Verify SECONDARY CONTAINMENT INTEGRITY is capable of being established in less than the DRAIN TIME,

2. Verify each secondary containment penetration flow path is capable of being isolated in less than the DRAIN TIME, and

3. Verify one standby gas treatment subsystem is capable of being placed in operation in less than the DRAIN TIME.

d. With DRAIN TIME less than 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months , immediately:

1. Initiate action to establish an additional method of water injection with water sources capable of maintaining RPV water level greater than TAF for greater than or equal to 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months ,***

2. Initiate action to establish SECONDARY CONTAINMENT INTEGRITY,

3. Initiate action to isolate each secondary containment penetration flow path or verify it can be automatically or manually isolated from the control room, and

4. Initiate action to verify one standby gas treatment subsystem is capable of being placed in operation.

e. With required ACTION and associated allowed outage time for ACTIONs c. or d. not met, or DRAIN TIME less than 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months , immediately initiate action to restore DRAIN TIME to greater than or equal to 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months .

- - The required injection/spray subsystem or an additional method of water injection shall be capable of operating without offsite electrical power.

LIMERICK - UNIT 1 3/4 5-6a Amendment No. 227

EMERGENCY CORE COOLING SYSTEMS SURVEILLANCE REQUIREMENTS 4.5.2.1 Verify DRAIN TIME is greater than or equal to 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months in accordance with the Surveillance Frequency Control Program.*

4.5.2.2 Verify, for a required LPCI subsystem, the suppression chamber water level is greater than or equal to 16 feet 0 inches in accordance with the Surveillance Frequency Control Program.

4.5.2.3 Verify, for a required CSS subsystem, that the suppression chamber water level is greater than or equal to 16 feet 0 inches or the condensate storage tank water level is greater than or equal to 29 feet 0 inches in accordance with the Surveillance Frequency Control Program.

4.5.2.4 Verify, for the required ECCS injection/spray subsystem, locations susceptible to gas accumulation are sufficiently filled with water in accordance with the Surveillance Frequency Control Program.

4.5.2.5 DELETEDVerify, for the required ECCS injection/spray subsystem, each manual, power operated, and automatic valve in the flow path, that is not locked, sealed, or otherwise secured in position, is in the correct position in accordance with the Surveillance Frequency Control Program.#^

4.5.2.6 Operate the required ECCS injection/spray subsystem through the recirculation line for greater than or equal to 10 minutes in accordance with the Surveillance Frequency Control Program.#^

4.5.2.7 Verify each valve credited for automatically isolating a penetration flow path actuates to the isolation position on an actual or simulated isolation signal in accordance with the Surveillance Frequency Control Program.

4.5.2.8 Verify the required ECCS injection/spray subsystem can be manually operated actuates on a manual initiation signal in accordance with the Surveillance Frequency Control Program.##

DELETED.

Operation may be through the test return line.Not required to be met for system vent flow paths open under administrative control.

^Credit may be taken for normal system operation to satisfy this surveillance requirement.Except that an automatic valve capable of automatic return to its ECCS position when an ECCS signal is present may be in position for another mode of operation.

1. Vessel injection/spray may be excluded.

LIMERICK - UNIT 1 3/4 5-7 Amendment No. 95, 186, 227

DEFINITIONS _

CORE ALTERATION 1.7 CORE ALTERATION shall be the movement of any fuel, sources, or reactivity control components within the reactor vessel with the vessel head removed and fuel in the vessel. The following exceptions are not considered to be CORE ALTERATIONS:

a) Movement of source range monitors, local power range monitors, intermediate range monitors, traversing incore probes, or special moveable detectors (including undervessel replacement); and b) Control rod movement, provided there are no fuel assemblies in the associated core cell.

Suspension of CORE ALTERATIONS shall not preclude completion of movement of a component to a safe position.

CORE OPERATING LIMITS REPORT 1.7a The CORE OPERATING LIMITS REPORT (COLR) is the unit-specific document that provides the core operating limits for the current operating reload cycle. These cycle-specific core operating limits shall be determined for each reload cycle in accordance with Specifications 6.9.1.9 thru 6.9.12. Plant operation within these limits is addressed in individual specifications.

CRITICAL POWER RATIO 1.8 The CRITICAL POWER RATIO (CPR) shall be the ratio of that power in the assembly which is calculated by application of the (GEXL) correlation to cause some point in the assembly to experience boiling transition, Information Only divided by the actual assembly operating power.

DOSE EQUIVALENT I-131 1.9 DOSE EQUIVALENT I-131 shall be that concentration of I-131, microcuries per gram, which alone would produce the same inhalation committed effective dose equivalent (CEDE) as the quantity and isotopic mixture of I-131, I-132, I-133, I-134, and I-135 actually present. The inhalation committed effective dose equivalent (CEDE) conversion factors used for this calculation shall be those listed in Table 2.1 of Federal Guidelines Report 11, Limiting Values of Radionuclide Intake and Air Concentration and Dose Conversion Factors for Inhalation, Submersion, and Ingestion, ORNL, 1989, as described in Regulatory Guide 1.183. The factors in the column headed effective yield doses corresponding to the CEDE.

DOWNSCALE TRIP SETPOINT (DTSP) 1.9a The downscale trip setpoint associated with the Rod Block Monitor (RBM) rod block trip setting.

DRAIN TIME 1.9b The DRAIN TIME is the time it would take for the water inventory in and above the Reactor Pressure Vessel (RPV) to drain to the top of the active fuel (TAF) seated in the RPV assuming:

a) The water inventory above the TAF is divided by the limiting drain rate; b) The limiting drain rate is the larger of the drain rate through a single penetration flow path with the highest flow rate, or the sum of the drain rates through multiple penetration flow paths LIMERICK - UNIT 2 1-2 Amendment No. 4, 48, 49, 136, 146, 190

DEFINITIONS DRAIN TIME (Continued) susceptible to a common mode failure (e.g., seismic event, loss of normal power, single human error), for all penetration flow paths below the TAF except:

1. Penetration flow paths connected to an intact closed system, or isolated by manual or automatic valves that are closed and administratively controlled locked, sealed, or otherwise secured in the closed position, blank flanges, or other devices that prevent flow of reactor coolant through the penetration flow paths;

2. Penetration flow paths capable of being isolated by valves that will close automatically without offsite power prior to the RPV water level being equal to the TAF when actuated by RPV water level isolation instrumentation; or

3. Penetration flow paths with isolation devices that can be closed prior to the RPV water level being equal to the TAF by a dedicated operator trained in the task, who is in continuous communication with the control room, is stationed at the controls, and is capable of closing the penetration flow path isolation device without offsite power.

c) The penetration flow paths required to be evaluated per paragraph b) are assumed to open instantaneously and are not subsequently isolated, and no water is assumed to be subsequently added to the RPV water inventory; d) No additional draining events occur; and e) Realistic cross-sectional areas and drain rates are used.

A bounding DRAIN TIME may be used in lieu of a calculated value.

1.10 (Deleted)

EMERGENCY CORE COOLING SYSTEM (ECCS) RESPONSE TIME 1.11 The EMERGENCY CORE COOLING SYSTEM (ECCS) RESPONSE TIME shall be that time interval from when the monitored parameter exceeds its ECCS actuation set-point at the channel sensor until the ECCS equipment is capable of performing its safety function, i.e., the valves travel to their required positions, pump discharge pressures reach their required values, etc.

Times shall include diesel generator starting and sequence loading delays where applicable. The response time may be measured by any series of sequential, overlapping or total steps such that the entire response time is measured.

LIMERICK - UNIT 2 1-2a Amendment No. 4, 48, 49, 136, 146, 190

INSTRUMENTATION 3/4.3.3.A REACTOR PRESSURE VESSEL (RPV) WATER INVENTORY CONTROL (WIC)

INSTRUMENTATION LIMITING CONDITION FOR OPERATION 3.3.3.A The RPV Water Inventory Control (WIC) instrumentation channels shown in Table 3.3.3.A-1 shall be OPERABLE.

APPLICABILITY: As shown in Table 3.3.3.A-1 ACTION:

a. With one or more channels inoperable in a trip system, take the ACTION referenced in Table 3.3.3.A-1 for the trip system.

SURVEILLANCE REQUIREMENTS 4.3.3.1.A Each RPV Water Inventory Control (WIC) instrumentation channel shall be demonstrated OPERABLE by performance of the CHANNEL CHECK and, CHANNEL FUNCTIONAL TEST and LOGIC SYSTEM FUNCTIONAL TEST as shown in Table 4.3.3.A-1 and at the frequencies specified in the Surveillance Frequency Control Program unless otherwise noted in Table 4.3.3.A-1.

LIMERICK - UNIT 2 3/4 3-41a Amendment No. 190

TABLE 3.3.3.A-1 RPV WATER INVENTORY CONTROL (WIC) INSTRUMENTATION MINIMUM OPERABLE CHANNELS PER APPLICABLE TRIP OPERATIONAL TRIP FUNCTION Insert: DELETED FUNCTION CONDITIONS ACTION

1. CORE SPRAY SYSTEM

a. Reactor Vessel Pressure - Low (Permissive) 6(a) 4, 5 39

b. Manual Initiation 2(a)(c) 4, 5 40

2. LOW PRESSURE COOLANT INJECTION MODE OF RHR SYSTEM

a. Injection Valve Differential Pressure - Low (Permissive) 1/valve(a) 4, 5 39

b. Manual Initiation 1(a) 4, 5 40

3. RHR SYSTEM SHUTDOWN COOLING MODE ISOLATION

a. Reactor Vessel Water Level Low - Level 3 2 in one (b) 38 trip system

4. REACTOR WATER CLEANUP SYSTEM ISOLATION

a. Reactor Vessel Water Level -

Low, Low - Level 2 2 in one (b) 38 trip system (a) Associated with an ECCS subsystem required to be OPERABLE by LCO 3.5.2, "REACTOR PRESSURE VESSEL (RPV) WATER INVENTORY CONTROL (WIC)."

(b) When automatic isolation of the associated penetration flow path(s) is credited in calculating DRAIN TIME.

(c) The manual initiation push buttons start the respective core spray pump and diesel generator. The "A" and "B" logic manual push buttons also actuate an initiation permissive in the injection valve opening logic.

Insert: DELETED LIMERICK - UNIT 2 3/4 3-41b Amendment No. 190

TABLE 3.3.3.A-1 (Continued)

RPV WATER INVENTORY CONTROL (WIC) INSTRUMENTATION ACTION STATEMENTS ACTION 38 - Immediately initiate actions to place channel in trip, or Ddeclare the associated trip system for the penetration flow path(s) incapable of automatic isolation and initiate action to calculate DRAIN TIME.

ACTION 39 - Within 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months , place channel in trip. Otherwise, declare associated low pressure ECCS injection/spray subsystem inoperable.

ACTION 40 - Within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months , restore channel to OPERABLE status. Otherwise, declare associated low pressure ECCS injection/spray subsystem inoperable.

Insert: DELETED LIMERICK - UNIT 2 3/4 3-41c Amendment No. 190

TABLE 3.3.3.A-2 RPV WATER INVENTORY CONTROL (WIC) INSTRUMENTATION SETPOINTS ALLOWABLE TRIP FUNCTION VALUE Insert: DELETED

1. CORE SPRAY SYSTEM

a. Reactor Vessel Pressure - Low (Permissive) > 435 psig

b. Manual Initiation (decreasing) N.A.

2. LOW PRESSURE COOLANT INJECTION MODE OF RHR SYSTEM

a. Injection Valve Differential Pressure - Low (Permissive) < 84 psid

b. Manual Initiation N.A.

3. RHR SYSTEM SHUTDOWN COOLING MODE ISOLATION

a. Reactor Vessel Water Level -

Low - Level 3 11.0 inches

4. REACTOR WATER CLEANUP SYSTEM ISOLATION

a. Reactor Vessel Water Level -

Low, Low - Level 2 -45 inches LIMERICK - UNIT 2 3/4 3-41d Amendment No. 190

TABLE 4.3.3.A-1 RPV WATER INVENTORY CONTROL (WIC) INSTRUMENTATION SURVEILLANCE REQUIREMENTS CHANNEL LOGIC SYSTEM OPERATIONAL CHANNEL FUNCTIONAL FUNCTIONAL CONDITIONS FOR WHICH TRIP FUNCTION CHECK(a) TEST(a) TEST(a) SURVEILLANCE REQUIRED Insert: DELETED

1. CORE SPRAY SYSTEM

a. Reactor Vessel Pressure - Low (Permissive) N.A. 4, 5

b. Manual Initiation N.A. N.A. 4, 5

2. LOW PRESSURE COOLANT INJECTION MODE OF RHR SYSTEM

a. Injection Valve Differential Pressure Low (Permissive) N.A. 4, 5

b. Manual Initiation N.A. N.A. 4, 5

3. RHR SYSTEM SHUTDOWN COOLING MODE ISOLATION

a. Reactor Vessel Water Level Low - Level 3 N.A. (b)

4. REACTOR WATER CLEANUP SYSTEM ISOLATION

a. Reactor Vessel Water Level -

Low, Low - Level 2 N.A. (b)

(a) Frequencies are specified in the Surveillance Frequency Control Program unless otherwise noted in the table.

(b) When automatic isolation of the associated penetration flow path(s) is credited in calculating DRAIN TIME.

LIMERICK - UNIT 2 3/4 3-41e Amendment No. 190

EMERGENCY CORE COOLING SYSTEMS LIMITING CONDITION FOR OPERATION (Continued)

ACTION:

c. With DRAIN TIME less than 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months and greater than or equal to 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months , within 4 hour4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months s:

1. Verify SECONDARY CONTAINMENT INTEGRITY is capable of being established in less than the DRAIN TIME,

2. Verify each secondary containment penetration flow path is capable of being isolated in less than the DRAIN TIME, and

3. Verify one standby gas treatment subsystem is capable of being placed in operation in less than the DRAIN TIME.

d. With DRAIN TIME less than 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months , immediately:

1. Initiate action to establish an additional method of water injection with water sources capable of maintaining RPV water level greater than TAF for greater than or equal to 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months ,***

2. Initiate action to establish SECONDARY CONTAINMENT INTEGRITY,

3. Initiate action to isolate each secondary containment penetration flow path or verify it can be automatically or manually isolated from the control room, and

4. Initiate action to verify one standby gas treatment subsystem is capable of being placed in operation.

e. With required ACTION and associated allowed outage time for ACTIONs c. or d. not met, or DRAIN TIME less than 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months , immediately initiate action to restore DRAIN TIME to greater than or equal to 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months .

- - The required injection/spray subsystem or an additional method of water injection shall be capable of operating without offsite electrical power.

LIMERICK - UNIT 2 3/4 5-6a Amendment No. 190

EMERGENCY CORE COOLING SYSTEMS SURVEILLANCE REQUIREMENTS 4.5.2.1 Verify DRAIN TIME is greater than or equal to 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months in accordance with the Surveillance Frequency Control Program.*

4.5.2.2 Verify, for a required LPCI subsystem, the suppression chamber water level is greater than or equal to 16 feet 0 inches in accordance with the Surveillance Frequency Control Program.

4.5.2.3 Verify, for a required CSS subsystem, that the suppression chamber water level is greater than or equal to 16 feet 0 inches or the condensate storage tank water level is greater than or equal to 29 feet 0 inches in accordance with the Surveillance Frequency Control Program.

4.5.2.4 Verify, for the required ECCS injection/spray subsystem, locations susceptible to gas accumulation are sufficiently filled with water in accordance with the Surveillance Frequency Control Program.

4.5.2.5 DELETEDVerify, for the required ECCS injection/spray subsystem, each manual, power operated, and automatic valve in the flow path, that is not locked, sealed, or otherwise secured in position, is in the correct position in accordance with the Surveillance Frequency Control Program.#^

4.5.2.6 Operate the required ECCS injection/spray subsystem through the recirculation line for greater than or equal to 10 minutes in accordance with the Surveillance Frequency Control Program.#^

4.5.2.7 Verify each valve credited for automatically isolating a penetration flow path actuates to the isolation position on an actual or simulated isolation signal in accordance with the Surveillance Frequency Control Program.

4.5.2.8 Verify the required ECCS injection/spray subsystem can be manually operated actuates on a manual initiation signal in accordance with the Surveillance Frequency Control Program.##

DELETED.

Operation may be through the test return line.Not required to be met for system vent flow paths open under administrative control.

^Credit may be taken for normal system operation to satisfy this surveillance requirement.Except that an automatic valve capable of automatic return to its ECCS position when an ECCS signal is present may be in position for another mode of operation.

1. Vessel injection/spray may be excluded.

LIMERICK - UNIT 2 3/4 5-7 Amendment No. 59, 147, 190

ATTACHMENT 2 License Amendment Request Limerick Generating Station, Units 1 and 2 Docket Nos. 50-352 and 50-353 Application to Revise Technical Specifications to Adopt TSTF-582, "Reactor Pressure Vessel Water Inventory Control (RPV WIC) Enhancements" Proposed Technical Specifications Bases Markup Pages Unit 1 and Unit 2 TS Bases Pages B 3/4 3-2b B 3/4 3-2c B 3/4 3-2d B 3/4 5-3a B 3/4 5-3d B 3/4 5-3e B 3/4 5-3f

INSTRUMENTATION BASES 3/4.3.3.A RPV WATER INVENTORY CONTROL (WIC) INSTRUMENTATION (Continued) automatically without offsite power prior to the RPV water level being equal to the TAF when actuated by RPV water level isolation instrumentation.

The purpose of the RPV Water Inventory Control Instrumentation is to support the requirements of LCO 3.5.2, Reactor Pressure Vessel (RPV) Water Inventory Control (WIC), and the definition of DRAIN TIME. There are functions that are required for manual initiation or operation of the ECCS injection/spray subsystem required to be OPERABLE by LCO 3.5.2 and other functions that support automatic isolation of Residual Heat Removal (RHR) subsystem and Reactor Water Cleanup (RWCU) system penetration flow path(s) on low RPV water level.

The RPV Water Inventory Control Instrumentation supports operation of the Core Spray System (CSS) and the Low Pressure Coolant Injection (LPCI) system. The equipment involved with each of these systems is described in the Bases for LCO 3.5.2.

A double-ended guillotine break of the Reactor Coolant System (RCS) is not postulated considered in OPERATIONAL CONDITIONS 4 and 5 due to the reduced RCS pressure, reduced piping stresses, and ductile piping systems. Instead, an event is postulated considered in which an single operator error or initiating event allows draining of the RPV water inventory through a single penetration flow path with the highest flow rate, or the sum of the drain rates through multiple penetration flow paths susceptible to a common mode failure., e.g., seismic event, loss of normal power, or single human error. It is assumed, based on engineering judgment, that while in OPERATIONAL CONDITIONS 4 and 5, one low pressure ECCS injection/spray subsystem can be manually initiated to maintain adequate reactor vessel water level.

As discussed in References 1, 2, 3, 4, and 5, operating experience has shown RPV water inventory to be significant to public health and safety.

Therefore, RPV Water Inventory Control satisfies Criterion 4 of 10 CFR 50.36(c)(2)(ii).

Permissive and interlock setpoints are generally considered as nominal values without regard to measurement accuracy.

The specific Applicable Safety Analyses, LCO, and Applicability discussions are listed below on a Function-by-Function basis.

Core Spray System - Reactor Vessel Pressure - Low (Permissive) and Low Pressure Coolant Injection Mode of RHR System - Injection Valve Differential Pressure - Low (Permissive)

The low reactor vessel pressure signal for Core Spray and the injection valve low differential pressure signal for LPCI are used as permissives for the low pressure ECCS injection/spray subsystem manual injection functions. These functions ensure that, prior to opening the injection valves of the low pressure ECCS subsystems, the reactor pressure has fallen to a value below these subsystems' maximum design pressure. While it is assured during OPERATIONAL CONDITIONS 4 and 5 that the reactor vessel pressure will be below the ECCS maximum design pressure, the Reactor Vessel Pressure - Low signal and the Injection Valve Differential Pressure - Low signal are assumed to be OPERABLE and capable of permitting initiation of the ECCS.

The Reactor Vessel Pressure - Low signals are initiated from four pressure transmitters that sense the reactor vessel pressure. The transmitters are connected to four trip units. The outputs of the trip units are connected to relays whose contacts are arranged in a one-out-of-two taken twice logic.

LIMERICK - UNIT 1 B 3/4 3-2b Associated with Amendment No. 227

INSTRUMENTATION BASES 3/4.3.3.A RPV WATER INVENTORY CONTROL (WIC) INSTRUMENTATION (Continued)

The Injection Valve Differential Pressure - Low signals are initiated from four differential pressure transmitters (one per valve) that monitor the differential pressure across each LPCI injection valve.

The Allowable Values are low enough to prevent overpressuring the equipment in the low pressure ECCS. The instrument channels of the Reactor Vessel Pressure

- Low and Injection Valve Differential Pressure - Low Functions are required to be OPERABLE in OPERATIONAL CONDITIONS 4 and 5 when ECCS manual initiation is required to be OPERABLE by LCO 3.5.2.

Manual Initiation The Manual Initiation push button channels introduce signals into the appropriate ECCS logic to provide manual initiation capability. There is one push button for each of the CSS and LPCI subsystems (i.e., four for CSS and four for LPCI).

There is no Allowable Value for this Function since the channels are mechanically actuated based solely on the position of the push buttons. A channel of the Manual Initiation Function (one channel per subsystem) is required to be OPERABLE in OPERATIONAL CONDITIONS 4 and 5 when the associated ECCS subsystems are required to be OPERABLE per LCO 3.5.2.

RHR System Isolation - Reactor Vessel Water Level Low - Level 3 The definition of DRAIN TIME allows crediting the closing of penetration flow paths that are capable of being isolated by valves that will close automatically without offsite power prior to the RPV water level being equal to the TAF when actuated by RPV water level isolation instrumentation. The Reactor Vessel Water Level Low - Level 3 Function associated with RHR System isolation may be credited for automatic isolation of penetration flow paths associated with the RHR System.

Reactor Vessel Water Level Low - Level 3 signals are initiated from four level transmitters that sense the difference between the pressure due to a constant column of water (reference leg) and the pressure due to the actual water level (variable leg) in the vessel. While four channels (two channels per trip system) of the Reactor Vessel Water Level Low - Level 3 Function are available, only two channels (all in the same trip system) are required to be OPERABLE.

The Reactor Vessel Water Level Low - Level 3 Allowable Value was chosen to be the same as the Primary Containment Isolation Instrumentation Reactor Vessel Water Level Low - Level 3 Allowable Value (Table 3.3.2-2), since the capability to cool the fuel may be threatened.

The Reactor Vessel Water Level Low - Level 3 Function is only required to be OPERABLE when automatic isolation of the associated penetration flow path is credited in calculating DRAIN TIME. This Function isolates the Group 2 valves.

Reactor Water Cleanup (RWCU) System Isolation - Reactor Vessel Water Level -

Low, Low - Level 2 The definition of DRAIN TIME allows crediting the closing of penetration flow paths that are capable of being isolated by valves that will close automatically without offsite power prior to the RPV water level being equal to the TAF when actuated by RPV water level isolation instrumentation. The Reactor LIMERICK - UNIT 1 B 3/4 3-2c Associated with Amendment No. 227

INSTRUMENTATION BASES 3/4.3.3.A RPV WATER INVENTORY CONTROL (WIC) INSTRUMENTATION (Continued)

Vessel Water Level - Low, Low - Level 2 Function associated with RWCU System isolation may be credited for automatic isolation of penetration flow paths associated with the RWCU System. Reactor Vessel Water Level - Low, Low - Level 2 signals are initiated from four level transmitters that sense the difference between the pressure due to a constant column of water (reference leg) and the pressure due to the actual water level (variable leg) in the vessel. While four channels (two channels per trip system) of the Reactor Vessel Water Level - Low, Low - Level 2 Function are available, only two channels (all in the same trip system) are required to be OPERABLE.

The Reactor Vessel Water Level - Low, Low - Level 2 Allowable Value was chosen to be the same as the Primary Containment Isolation Instrumentation Reactor Vessel Water Level - Low, Low Level 2 Allowable Value (Table 3.3.2-2), since the capability to cool the fuel may be threatened.

The Reactor Vessel Water Level - Low, Low Level 2 Function is only required to be OPERABLE when automatic isolation of the associated penetration flow path is credited in calculating DRAIN TIME. This Function isolates the Group 3 valves.

Actions A note has been provided to modify the ACTIONs related to RPV Water Inventory Control instrumentation channels. The ACTIONs for inoperable RPV Water Inventory Control instrumentation channels provide appropriate compensatory measures for each inoperable RPV Water Inventory Control instrumentation channel.

ACTION a. directs taking the appropriate ACTION referenced in Table 3.3.3.A-

1. The applicable ACTION referenced in the table is Function dependent.

RHR System Shutdown Cooling Mode Isolation, Reactor Vessel Water Level Low

- Level 3, and Reactor Water Cleanup System Isolation, Reactor Vessel Water Level

- Low, Low - Level 2 functions are applicable when automatic isolation of the associated penetration flow path is credited in calculating DRAIN TIME. If the instrumentation is inoperable, ACTION 38 directs an immediate action to place the channel in trip. With the inoperable channel in the tripped condition, the remaining channel will isolate the penetration flow path on low water level. If both channels are inoperable and placed in trip, the penetration flow path will be isolated. Alternatively, ACTION 38 requires immediate declaration that the associated penetration flow path(s) to be immediately declared are incapable of automatic isolation and directs initiating action to calculate calculation of DRAIN TIME. The calculation cannot credit automatic isolation of the affected penetration flow paths.

Low reactor vessel pressure signals are used as permissives for the low pressure ECCS injection/spray subsystem manual injection functions. If the permissive is inoperable, manual initiation of ECCS is prohibited. Therefore, the permissive must be placed in the trip condition within 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months . With the permissive in the trip condition, manual initiation may be performed. Prior to placing the permissive in the tripped condition, the operator can take manual control of the pump and the injection valve to inject water into the RPV.

The allowed outage time of 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months is intended to allow the operator time to evaluate any discovered inoperabilities and to place the channel in trip.

The 24-hour allowed outage time was chosen to allow time for the operator to evaluate and repair any discovered inoperabilities. The allowed outage time is appropriate given the ability to manually start the ECCS pumps and open the injection valves and to manually ensure the pump does not overheat.

With the ACTION and associated allowed outage time of ACTION 39 or 40 not met, the associated low pressure ECCS injection/spray subsystem may be incapable of performing the intended function and must be declared inoperable immediately.

LIMERICK - UNIT 1 B 3/4 3-2d Associated with Amendment No. 227

EMERGENCY CORE COOLING SYSTEM BASES 3/4.5.2 - REACTOR PRESSURE VESSEL (RPV) WATER INVENTORY CONTROL (WIC)

Background:

The RPV contains penetrations below the top of the active fuel (TAF) that have the potential to drain the reactor coolant inventory to below the TAF. If the water level should drop below the TAF, the ability to remove decay heat is reduced, which could lead to elevated cladding temperatures and clad perforation. Safety Limit 2.1.4 requires the RPV water level to be above the top of the active irradiated fuel at all times to prevent such elevated cladding temperatures.

Applicable Safety Analysis:

With the unit in OPERATIONAL CONDITION 4 or 5, RPV water inventory control is not required to mitigate any events or accidents evaluated in the safety analyses. RPV water inventory control is required in OPERATIONAL CONDITIONS 4 and 5 to protect Safety Limit 2.1.4 and the fuel cladding barrier to prevent the release of radioactive material to the environment should an unexpected draining event occur.

A double-ended guillotine break of the Reactor Coolant System (RCS) is not postulated considered in OPERATIONAL CONDITIONS 4 and 5 due to the reduced RCS pressure, reduced piping stresses, and ductile piping systems. Instead, an event is considered in which an single operator error or initiating event allows draining of the RPV water inventory through a single penetration flow path with the highest flow rate, or the sum of the drain rates through multiple penetration flow paths susceptible to a common mode failure (an event that creates a drain path through multiple vessel penetrations located below top of active fuel, such as , e.g.,

seismic event (except when risk is assessed and managed in accordance with LCO 3.0.8), loss of normal power, or a single human error). It is assumed, based on engineering judgement, that while in OPERATIONAL CONDITIONS 4 and 5, one low pressure ECCS injection/spray subsystem can maintain adequate reactor vessel water level.

As discussed in References 1, 2, 3, 4, and 5, operating experience has shown RPV water inventory to be significant to public health and safety. Therefore, RPV Water Inventory Control satisfies Criterion 4 of 10 CFR 50.36(c)(2)(ii).

Limiting Condition for Operation:

The RPV water level must be controlled in OPERATIONAL CONDITIONS 4 and 5 to ensure that if an unexpected draining event should occur, the reactor coolant water level remains above the top of the active irradiated fuel as required by Safety Limit 2.1.4.

The Limiting Condition for Operation (LCO) requires the DRAIN TIME of RPV water inventory to the TAF to be 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months . A DRAIN TIME of 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months is considered reasonable to identify and initiate action to mitigate unexpected draining of reactor coolant. An event that could cause loss of RPV water inventory and result in the RPV water level reaching the TAF in greater than 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months does not represent a significant challenge to Safety Limit 2.1.4 and can be managed as part of normal plant operation.

One low pressure ECCS injection/spray subsystem is required to be OPERABLE and capable of being manually aligned and started from the control room to provide defense-in-depth should an unexpected draining event occur. OPERABILITY of the ECCS injection/spray subsystem includes any necessary valves, instrumentation, or controls needed to manually align and start the subsystem from the control room. A low pressure ECCS injection/spray subsystem consists of either one Core Spray System (CSS) subsystem or one Low Pressure Coolant Injection (LPCI) subsystem. Each CSS subsystem consists of two motor driven pumps, piping, and valves to transfer water from the suppression pool or condensate storage tank (CST) to the RPV. Each LPCI subsystem

consists of one motor driven pump, piping, and valves to transfer water from the suppression pool to the RPV.

LIMERICK - UNIT 1 B 3/4 5-3a Associated with Amendment No. 227 Information Only

EMERGENCY CORE COOLING SYSTEM BASES RPV WATER INVENTORY CONTROL (WIC) (Continued)

The secondary containment provides a control volume into which fission products can be contained, diluted, and processed prior to release to the environment.

Actions to immediately establish SECONDARY CONTAINMENT INTEGRITY are required. With SECONDARY CONTAINMENT INTEGRITY established, one SGT subsystem is capable of maintaining a negative pressure in the secondary containment with respect to the environment.

The secondary containment penetrations form a part of SECONDARY CONTAINMENT INTEGRITY. Actions to immediately verify that each secondary containment penetration flow path is isolated or to verify that it can be automatically or manually isolated from the control room are required.

One SGT subsystem is capable of maintaining the secondary containment at a negative pressure with respect to the environment and filter gaseous releases. Actions to immediately verify that at least one SGT subsystem is capable of being placed in operation are required. The required verification is an administrative activity and does not require manipulation or testing of equipment.

Action e. - If the ACTIONs and associated allowed outage times are not met or if the DRAIN TIME is less than 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months , actions must be initiated immediately to restore the DRAIN TIME to 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months . In this condition, there may be insufficient time to respond to an unexpected draining event to prevent the RPV water inventory from reaching the TAF. Note that ACTIONs are also applicable when DRAIN TIME is less than 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months .

Surveillance Requirements:

Surveillance Requirement (SR) 4.5.2.1 verifies that the DRAIN TIME of RPV water inventory to the TAF is 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months . The period of 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months is considered reasonable to identify and initiate action to mitigate draining of reactor coolant. Loss of RPV water inventory that would result in the RPV water level reaching the TAF in greater than 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months does not represent a significant challenge to Safety Limit 2.1.4 and can be managed as part of normal plant operation.

The definition of DRAIN TIME states that realistic cross-sectional areas and drain rates are used in the calculation. A realistic drain rate may be determined using a single, step-wise, or integrated calculation considering the changing RPV water level during a draining event. For a control rod RPV penetration flow path with the control rod drive mechanism removed and not replaced with a blank flange, the realistic cross-sectional area is based on the control rod blade seated in the control rod guide tube. If the control rod blade will be raised from the penetration to adjust or verify seating of the blade, the exposed cross-sectional area of the RPV penetration flow path is used.

The definition of DRAIN TIME excludes from the calculation those penetration flow paths connected to an intact closed system, or isolated by manual or automatic valves that are closed and administratively controlled locked, sealed, or otherwise secured in the closed position, blank flanges, or other devices that prevent flow of reactor coolant through the penetration flow paths. A blank flange or other bolted device must be connected with a sufficient number of bolts to prevent draining in the event of an Operating Basis Earthquake. Normal or expected leakage from closed systems or past isolation devices is permitted. Determination that a system is intact and closed or isolated must consider the status of branch lines and ongoing plant maintenance and testing activities.

The Residual Heat Removal (RHR) Shutdown Cooling System is only considered an intact closed system when misalignment issues (Reference 6) have been precluded by functional valve interlocks or by isolation devices, such that redirection of RPV water out of an RHR subsystem is precluded. Further, the RHR Shutdown Cooling System is only considered an intact closed system if its controls have not been transferred to Remote Shutdown, which disables the interlocks and isolation signals.

LIMERICK - UNIT 1 B 3/4 5-3d Associated with Amendment No. 227

EMERGENCY CORE COOLING SYSTEM BASES RPV WATER INVENTORY CONTROL (WIC) (Continued)

The exclusion of a single penetration flow paths, or multiple penetration flow paths susceptible to a common mode failure, from the determination of DRAIN TIME must should consider the potential effects of temporary alterations in support of maintenance a single operator error or initiating event on items supporting maintenance and testing (rigging, scaffolding, temporary shielding, piping plugs, snubber removal, freeze seals, etc.). If reasonable controls are implemented to prevent If failure of such temporary alterations from items could result and would cause causing a draining event from a closed system or between the RPV and the isolation device, the penetration flow path may not be excluded from the DRAIN TIME calculation. the effect of the temporary alterations on DRAIN TIME need not be considered. Reasonable controls include, but are not limited to, controls consistent with the guidance in NUMARC 93-01, "Industry Guideline for Monitoring the Effectiveness of Maintenance at Nuclear Power Plants,"

Revision 4, NUMARC 91-06, "Guidelines for Industry Actions to Assess Shutdown Management," or commitments to NUREG-0612, "Control of Heavy Loads at Nuclear Power Plants."

TS 4.0.1 requires SRs to be met between performances. Therefore, any changes in plant conditions that would change the DRAIN TIME requires that a new DRAIN TIME be determined.

SRs 4.5.2.2 and 4.5.2.3 - The minimum water level of 16 feet required for the suppression pool is periodically verified to ensure that the suppression pool will provide adequate net positive suction head (NPSH) for the CSS subsystem or LPCI subsystem pumps, recirculation volume, and vortex prevention. With the suppression pool water level less than the required limit, the required ECCS injection/spray subsystem is inoperable unless aligned to an OPERABLE CST.

The required CSS subsystem is OPERABLE if it can take suction from the CST, and the CST water level is sufficient to provide the required NPSH for the CSS pumps.

Therefore, a verification that either the suppression pool water level is greater than or equal to 16 feet 0 inches or that a CSS subsystem is aligned to take suction from the CST and the CST contains greater than or equal to 135,000 available gallons of water, equivalent to a level of 29 feet 0 inches, ensures that the CSS subsystem can supply the required makeup water to the RPV.

SR 4.5.2.4 - The flow path piping has the potential to develop voids and pockets of entrained air. Maintaining the pump discharge lines of the required ECCS injection/spray subsystems full of water ensures that the ECCS subsystem will perform properly. This may also prevent a water hammer following an ECCS actuation. initiation signal. One acceptable method of ensuring that the lines are full is to vent at the high points.

SR 4.5.2.5 -DELETED Verifying the correct alignment for manual, power operated, and automatic valves in the required ECCS subsystem flow paths provides assurance that the proper flow path will be available for ECCS operation. This SR does not apply to valves that are locked, sealed, or otherwise secured in position, since these valves were verified to be in the correct position prior to locking, sealing, or securing. A valve that receives an initiation signal is allowed to be in a nonaccident position provided the valve will automatically reposition in the proper stroke time. This SR does not require any testing or valve manipulation; rather, it involves verification that those valves capable of potentially being mispositioned are in the correct position. This SR does not apply to valves that cannot be inadvertently misaligned, such as check valves.

SR 4.5.2.6 - Verifying that the required ECCS injection/spray subsystem can be manually aligned, and the pump started and operated for at least 10 minutes demonstrates that the subsystem is available to mitigate a draining event. This surveillance requirement is modified by two footnotes. The first states that tTesting the ECCS injection/spray subsystem may be done through the test return line

recirculation full flow test line is necessary to avoid overfilling the refueling cavity. The second states that credit for meeting the surveillance requirement may be taken for normal system operation that satisfies the surveillance requirement, such as using the RHR mode of LPCI for greater than or equal to 10 minutes. The minimum operating time of 10 minutes was based on engineering judgement.

SR 4.5.2.7 - Verifying that each valve credited for automatically isolating a penetration flow path actuates to the isolation position on an actual or simulated RPV water level isolation signal is required to prevent RPV water inventory from dropping below the TAF should an unexpected draining event occur.

LIMERICK - UNIT 1 B 3/4 5-3e Associated with Amendment No. 227

EMERGENCY CORE COOLING SYSTEM BASES RPV WATER INVENTORY CONTROL (WIC) (Continued)

SR 4.5.2.8 - The required ECCS subsystem is required to actuate on a manual initiation signal. This surveillance verifies that a manual initiation signal will cause the required CSS subsystem or LPCI subsystem can be manually aligned and started from the control room, including any necessary valve alignment, instrumentation, or controls, to transfer water from the suppression pool or CST to the RPV. to start and operate as designed, including pump startup and actuation of all automatic valves to their required positions. This SR is modified by a note that excludes vessel injection/spray during the surveillance. Since all active components are testable and full flow can be demonstrated by recirculation through the test line, coolant injection into the RPV is not required during the surveillance.

The Surveillance Frequencies in the above SRs are controlled under the Surveillance Frequency Controlled Program.

REFERENCES

1. Information Notice 84-81, "Inadvertent Reduction in Primary Coolant Inventory in Boiling Water Reactors During Shutdown and Startup," November 1984.

2. Information Notice 86-74, "Reduction of Reactor Coolant Inventory Because of Misalignment of RHR Valves," August 1986.

3. Generic Letter 92-04, "Resolution of the Issues Related to Reactor Vessel Water Level Instrumentation in BWRs Pursuant to 10 CFR 50.54(f)," August 1992.

4. NRC Bulletin 93-03, "Resolution of Issues Related to Reactor Vessel Water Level Instrumentation in BWRs," May 1993.

5. Information Notice 94-52, "Inadvertent Containment Spray and Reactor Vessel Draindown at Millstone 1," July 1994.

6. General Electric Service Information Letter No. 388, "RHR Valve Misalignment During Shutdown Cooling Operation for BWR 3/4/5/6," February 1983.

LIMERICK - UNIT 1 B 3/4 5-3f Associated with Amendment No. 227

INSTRUMENTATION BASES 3/4.3.3.A RPV WATER INVENTORY CONTROL (WIC) INSTRUMENTATION (Continued) if they will be isolated by valves that will close automatically without offsite power prior to the RPV water level being equal to the TAF when actuated by RPV water level isolation instrumentation.

The purpose of the RPV Water Inventory Control Instrumentation is to support the requirements of LCO 3.5.2, Reactor Pressure Vessel (RPV) Water Inventory Control (WIC), and the definition of DRAIN TIME. There are functions that are required for manual initiation or operation of the ECCS injection/spray subsystem required to be OPERABLE by LCO 3.5.2 and other functions that support automatic isolation of Residual Heat Removal (RHR) subsystem and Reactor Water Cleanup (RWCU) system penetration flow path(s) on low RPV water level.

The RPV Water Inventory Control Instrumentation supports operation of the Core Spray System (CSS) and the Low Pressure Coolant Injection (LPCI) system.

The equipment involved with each of these systems is described in the Bases for LCO 3.5.2.

A double-ended guillotine break of the Reactor Coolant System (RCS) is not postulated considered in OPERATIONAL CONDITIONS 4 and 5 due to the reduced RCS pressure, reduced piping stresses, and ductile piping systems. Instead, an event is postulated considered in which an single operator error or initiating event allows draining of the RPV water inventory through a single penetration flow path with the highest flow rate, or the sum of the drain rates through multiple penetration flow paths susceptible to a common mode failure., e.g., seismic event, loss of normal power, or single human error. It is assumed, based on engineering judgment, that while in OPERATIONAL CONDITIONS 4 and 5, one low pressure ECCS injection/spray subsystem can be manually initiated to maintain adequate reactor vessel water level.

As discussed in References 1, 2, 3, 4, and 5, operating experience has shown RPV water inventory to be significant to public health and safety. Therefore, RPV Water Inventory Control satisfies Criterion 4 of 10 CFR 50.36(c)(2)(ii).

Permissive and interlock setpoints are generally considered as nominal values without regard to measurement accuracy.

The specific Applicable Safety Analyses, LCO, and Applicability discussions are listed below on a Function-by-Function basis.

Core Spray Systems - Reactor Vessel Pressure - Low (Permissive) and Low Pressure Coolant Injection Mode of RHR System - Injection Valve Differential Pressure -

Low (Permissive)

The low reactor vessel pressure signal for Core Spray and the injection valve low differential pressure signal for LPCI are used as permissives for the low pressure ECCS injection/spray subsystem manual injection functions. These functions ensure that, prior to opening the injection valves of the low pressure ECCS subsystems, the reactor pressure has fallen to a value below these subsystems' maximum design pressure. While it is assured during OPERATIONAL CONDITIONS 4 and 5 that the reactor vessel pressure will be below the ECCS maximum design pressure, the Reactor Vessel Pressure - Low signal and the Injection Valve Differential Pressure - Low signal are assumed to be OPERABLE and capable of permitting initiation of the ECCS.

The Reactor Vessel Pressure - Low signals are initiated from four pressure transmitters that sense the reactor vessel pressure. The transmitters are connected to four trip units. The outputs of the trip units are connected to relays whose contacts are arranged in a one-out-of-two taken twice logic.

LIMERICK - UNIT 2 B 3/4 3-2b Associated with Amendment No. 190

INSTRUMENTATION BASES 3/4.3.3.A RPV WATER INVENTORY CONTROL (WIC) INSTRUMENTATION (Continued)

The Injection Valve Differential Pressure - Low signals are initiated from four differential pressure transmitters (one per valve) that monitor the differential pressure across each LPCI injection valve.

The Allowable Values are low enough to prevent overpressuring the equipment in the low pressure ECCS. The instrument channels of the Reactor Vessel Pressure - Low and Injection Valve Differential Pressure - Low Functions are required to be OPERABLE in OPERATIONAL CONDITIONS 4 and 5 when ECCS manual initiation is required to be OPERABLE by LCO 3.5.2.

Manual Initiation The Manual Initiation push button channels introduce signals into the appropriate ECCS logic to provide manual initiation capability. There is one push button for each of the CSS and LPCI subsystems (i.e., four for CSS and four for LPCI).

There is no Allowable Value for this Function since the channels are mechanically actuated based solely on the position of the push buttons. A channel of the Manual Initiation Function (one channel per subsystem) is required to be OPERABLE in OPERATIONAL CONDITIONS 4 and 5 when the associated ECCS subsystems are required to be OPERABLE per LCO 3.5.2.

RHR System Isolation - Reactor Vessel Water Level Low - Level 3 The definition of DRAIN TIME allows crediting the closing of penetration flow paths that are capable of being isolated by valves that will close automatically without offsite power prior to the RPV water level being equal to the TAF when actuated by RPV water level isolation instrumentation. The Reactor Vessel Water Level Low - Level 3 Function associated with RHR System isolation may be credited for automatic isolation of penetration flow paths associated with the RHR System.

Reactor Vessel Water Level Low - Level 3 signals are initiated from four level transmitters that sense the difference between the pressure due to a constant column of water (reference leg) and the pressure due to the actual water level (variable leg) in the vessel. While four channels (two channels per trip system) of the Reactor Vessel Water Level Low - Level 3 Function are available, only two channels (all in the same trip system) are required to be OPERABLE.

The Reactor Vessel Water Level Low - Level 3 Allowable Value was chosen to be the same as the Primary Containment Isolation Instrumentation Reactor Vessel Water Level Low - Level 3 Allowable Value (Table 3.3.2-2), since the capability to cool the fuel may be threatened.

The Reactor Vessel Water Level Low - Level 3 Function is only required to be OPERABLE when automatic isolation of the associated penetration flow path is credited in calculating DRAIN TIME. This Function isolates the Group 2 valves.

Reactor Water Cleanup (RWCU) System Isolation - Reactor Vessel Water Level -

Low, Low - Level 2 The definition of DRAIN TIME allows crediting the closing of penetration flow paths that are capable of being isolated by valves that will close automatically without offsite power prior to the RPV water level being equal to the TAF when actuated by RPV water level isolation instrumentation. The Reactor Vessel Water Level - Low, Low - Level 2 Function associated with RWCU System isolation may be credited for automatic isolation of penetration flow paths associated with the RWCU System.

LIMERICK - UNIT 2 B 3/4 3-2c Associated with Amendment No. 190

INSTRUMENTATION BASES 3/4.3.3.A RPV WATER INVENTORY CONTROL (WIC) INSTRUMENTATION (Continued)

Reactor Vessel Water Level - Low, Low - Level 2 signals are initiated from four level transmitters that sense the difference between the pressure due to a constant column of water (reference leg) and the pressure due to the actual water level (variable leg) in the vessel. While four channels (two channels per trip system) of the Reactor Vessel Water Level - Low, Low - Level 2 Function are available, only two channels (all in the same trip system) are required to be OPERABLE.

The Reactor Vessel Water Level - Low, Low - Level 2 Allowable Value was chosen to be the same as the Primary Containment Isolation Instrumentation Reactor Vessel Water Level - Low, Low Level 2 Allowable Value (Table 3.3.2-2), since the capability to cool the fuel may be threatened.

The Reactor Vessel Water Level - Low, Low - Level 2 Function is only required to be OPERABLE when automatic isolation of the associated penetration flow path is credited in calculating DRAIN TIME. This Function isolates the Group 3 valves.

Actions A note has been provided to modify the ACTIONs related to RPV Water Inventory Control instrumentation channels. The ACTIONs for inoperable RPV Water Inventory Control instrumentation channels provide appropriate compensatory measures for each inoperable RPV Water Inventory Control instrumentation channel.

ACTION a. directs taking the appropriate ACTION referenced in Table 3.3.3.A-

1. The applicable ACTION referenced in the table is Function dependent.

RHR System Shutdown Cooling Mode Isolation, Reactor Vessel Water Level Low -

Level 3, and Reactor Water Cleanup System Isolation, Reactor Vessel Water Level -

Low, Low - Level 2 functions are applicable when automatic isolation of the associated penetration flow path is credited in calculating DRAIN TIME. If the instrumentation is inoperable, ACTION 38 directs animmediate action to place the channel in trip. With the inoperable channel in the tripped condition, the remaining channel will isolate the penetration flow path on low water level. If both channels are inoperable and placed in trip, the penetration flow path will be isolated. Alternatively, ACTION 38 requires immediate declaration that the associated penetration flow path(s) to be immediately declared are incapable of automatic isolation and directs initiating action to calculate calculation of DRAIN TIME. The calculation cannot credit automatic isolation of the affected penetration flow paths.

Low reactor vessel pressure signals are used as permissives for the low pressure ECCS injection/spray subsystem manual injection functions. If the permissive is inoperable, manual initiation of ECCS is prohibited. Therefore, the permissive must be placed in the trip condition within 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months . With the permissive in the trip condition, manual initiation may be performed. Prior to placing the permissive in the tripped condition, the operator can take manual control of the pump and the injection valve to inject water into the RPV.

The allowed outage time of 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months is intended to allow the operator time to evaluate any discovered inoperabilities and to place the channel in trip.

The 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months allowed outage time was chosen to allow time for the operator to evaluate and repair any discovered inoperabilities. The allowed outage time is appropriate given the ability to manually start the ECCS pumps and open the injection valves and to manually ensure the pump does not overheat.

With the ACTION and associated allowed outage time of ACTION 39 or 40 not met, the associated low pressure ECCS injection/spray subsystem may be incapable

of performing the intended function, and must be declared inoperable immediately.

LIMERICK - UNIT 2 B 3/4 3-2d Associated with Amendment No. 190

EMERGENCY CORE COOLING SYSTEM BASES 3/4.5.2 - REACTOR PRESSURE VESSEL (RPV) WATER INVENTORY CONTROL (WIC)

Background:

The RPV contains penetrations below the top of the active fuel (TAF) that have the potential to drain the reactor coolant inventory to below the TAF. If the water level should drop below the TAF, the ability to remove decay heat is reduced, which could lead to elevated cladding temperatures and clad perforation. Safety Limit 2.1.4 requires the RPV water level to be above the top of the active irradiated fuel at all times to prevent such elevated cladding temperatures.

Applicable Safety Analysis:

With the unit in OPERATIONAL CONDITION 4 or 5, RPV water inventory control is not required to mitigate any events or accidents evaluated in the safety analyses.

RPV water inventory control is required in OPERATIONAL CONDITIONS 4 and 5 to protect Safety Limit 2.1.4 and the fuel cladding barrier to prevent the release of radioactive material to the environment should an unexpected draining event occur.

A double-ended guillotine break of the Reactor Coolant System (RCS) is not postulated considered in OPERATIONAL CONDITIONS 4 and 5 due to the reduced RCS pressure, reduced piping stresses, and ductile piping systems. Instead, an event is considered in which an single operator error or initiating event allows draining of the RPV water inventory through a single penetration flow path with the highest flow rate, or the sum of the drain rates through multiple penetration flow paths susceptible to a common mode failure (an event that creates a drain path through multiple vessel penetrations located below top of active fuel, such as, e.g.,

seismic event (except when risk is assessed and managed in accordance with LCO 3.0.8), loss of normal power, or a single human error. It is assumed, based on engineering judgement, that while in OPERATIONAL CONDITIONS 4 and 5, one low pressure ECCS injection/spray subsystem can maintain adequate reactor vessel water level.

As discussed in References 1, 2, 3, 4, and 5, operating experience has shown RPV water inventory to be significant to public health and safety. Therefore, RPV Water Inventory Control satisfies Criterion 4 of 10 CFR 50.36(c)(2)(ii).

Limiting Condition for Operation:

The RPV water level must be controlled in OPERATIONAL CONDITIONS 4 and 5 to ensure that if an unexpected draining event should occur, the reactor coolant water level remains above the top of the active irradiated fuel as required by Safety Limit 2.1.4.

The Limiting Condition for Operation (LCO) requires the DRAIN TIME of RPV water inventory to the TAF to be 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months . A DRAIN TIME of 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months is considered reasonable to identify and initiate action to mitigate unexpected draining of reactor coolant. An event that could cause loss of RPV water inventory and result in the RPV water level reaching the TAF in greater than 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months does not represent a significant challenge to Safety Limit 2.1.4 and can be managed as part of normal plant operation.

One low pressure ECCS injection/spray subsystem is required to be OPERABLE and capable of being manually aligned and started from the control room to provide defense-in-depth should an unexpected draining event occur. OPERABILITY of the ECCS injection/spray subsystem includes any necessary valves, instrumentation, or controls needed to manually align and start the subsystem from the control room. A low pressure ECCS injection/spray subsystem consists of either one Core Spray System (CSS) subsystem or one Low Pressure Coolant Injection (LPCI) subsystem.

Each CSS subsystem consists of two motor driven pumps, piping, and valves to transfer water from the suppression pool or condensate storage tank (CST) to the

RPV. Each LPCI subsystem consists of one motor driven pump, piping, and valves to transfer water from the suppression pool to the RPV.

LIMERICK - UNIT 2 B 3/4 5-3a Associated with Amendment No. 190 Information Only

EMERGENCY CORE COOLING SYSTEM BASES RPV WATER INVENTORY CONTROL (WIC) (Continued)

The secondary containment provides a control volume into which fission products can be contained, diluted, and processed prior to release to the environment.

Actions to immediately establish SECONDARY CONTAINMENT INEGRITY are required. With SECONDARY CONTAINMENT INEGRITY established, one SGT subsystem is capable of maintaining a negative pressure in the secondary containment with respect to the environment.

The secondary containment penetrations form a part of SECONDARY CONTAINMENT INEGRITY. Actions to immediately verify that each secondary containment penetration flow path is isolated or to verify that it can be automatically or manually isolated from the control room are required.

One SGT subsystem is capable of maintaining the secondary containment at a negative pressure with respect to the environment and filter gaseous releases.

Actions to immediately verify that at least one SGT subsystem is capable of being placed in operation are required. The required verification is an administrative activity and does not require manipulation or testing of equipment.

Action e. - If the ACTIONs and associated allowed outage times are not met or if the DRAIN TIME is less than 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months , actions must be initiated immediately to restore the DRAIN TIME to 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months . In this condition, there may be insufficient time to respond to an unexpected draining event to prevent the RPV water inventory from reaching the TAF. Note that ACTIONs are also applicable when DRAIN TIME is less than 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months .

Surveillance Requirements:

Surveillance Requirement (SR) 4.5.2.1 verifies that the DRAIN TIME of RPV water inventory to the TAF is 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months . The period of 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months is considered reasonable to identify and initiate action to mitigate draining of reactor coolant.

Loss of RPV water inventory that would result in the RPV water level reaching the TAF in greater than 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months does not represent a significant challenge to Safety Limit 2.1.4 and can be managed as part of normal plant operation.

The definition of DRAIN TIME states that realistic cross-sectional areas and drain rates are used in the calculation. A realistic drain rate may be determined using a single, step-wise, or integrated calculation considering the changing RPV water level during a draining event. For a control rod RPV penetration flow path with the control rod drive mechanism removed and not replaced with a blank flange, the realistic cross-sectional area is based on the control rod blade seated in the control rod guide tube. If the control rod blade will be raised from the penetration to adjust or verify seating of the blade, the exposed cross-sectional area of the RPV penetration flow path is used.

The definition of DRAIN TIME excludes from the calculation those penetration flow paths connected to an intact closed system, or isolated by manual or automatic valves that are closed and administratively controlled locked, sealed, or otherwise secured in the closed position, blank flanges, or other devices that prevent flow of reactor coolant through the penetration flow paths. A blank flange or other bolted device must be connected with a sufficient number of bolts to prevent draining in the event of an Operating Basis Earthquake. Normal or expected leakage from closed systems or past isolation devices is permitted. Determination that a system is intact and closed or isolated must consider the status of branch lines and ongoing plant maintenance and testing activities.

The Residual Heat Removal (RHR) Shutdown Cooling System is only considered an intact closed system when misalignment issues (Reference 6) have been precluded by functional valve interlocks or by isolation devices, such that redirection of RPV water out of an RHR subsystem is precluded. Further, the RHR Shutdown Cooling System is only considered an intact closed system if its controls have not been transferred to Remote Shutdown, which disables the interlocks and isolation signals.

LIMERICK - UNIT 2 B 3/4 5-3d Associated with Amendment No. 190

EMERGENCY CORE COOLING SYSTEM BASES RPV WATER INVENTORY CONTROL (WIC) (Continued)

The exclusion of a single penetration flow paths, or multiple penetration flow paths susceptible to a common mode failure, from the determination of DRAIN TIME must should consider the potential effects of temporary alterations in support of maintenance a single operator error or initiating event on items supporting maintenance and testing (rigging, scaffolding, temporary shielding, piping plugs, snubber removal, freeze seals, etc.). If reasonable controls are implemented to prevent If failure of such temporary alterations from items could result and would causecausing a draining event from a closed system or between the RPV and the isolation device, the penetration flow path may not be excluded from the DRAIN TIME calculation.the effect of the temporary alterations on DRAIN TIME need not be considered. Reasonable controls include, but are not limited to, controls consistent with the guidance in NUMARC 93-01, "Industry Guideline for Monitoring the Effectiveness of Maintenance at Nuclear Power Plants," Revision 4, NUMARC 91- 06, "Guidelines for Industry Actions to Assess Shutdown Management," or commitments to NUREG-0612, "Control of Heavy Loads at Nuclear Power Plants."

TS 4.0.1 requires SRs to be met between performances. Therefore, any changes in plant conditions that would change the DRAIN TIME requires that a new DRAIN TIME be determined.

SRs 4.5.2.2 and 4.5.2.3 - The minimum water level of 16 feet required for the suppression pool is periodically verified to ensure that the suppression pool will provide adequate net positive suction head (NPSH) for the CSS subsystem or LPCI subsystem pumps, recirculation volume, and vortex prevention. With the suppression pool water level less than the required limit, the required ECCS injection/spray subsystem is inoperable unless aligned to an OPERABLE CST.

The required CSS subsystem is OPERABLE if it can take suction from the CST, and the CST water level is sufficient to provide the required NPSH for the CSS pumps. Therefore, a verification that either the suppression pool water level is greater than or equal to 16 feet 0 inches or that a CSS subsystem is aligned to take suction from the CST and the CST contains greater than or equal to 135,000 available gallons of water, equivalent to a level of 29 feet 0 inches, ensures that the CSS subsystem can supply the required makeup water to the RPV.

SR 4.5.2.4 - The flow path piping has the potential to develop voids and pockets of entrained air. Maintaining the pump discharge lines of the required ECCS injection/spray subsystems full of water ensures that the ECCS subsystem will perform properly. This may also prevent a water hammer following an ECCS actuation initiation signal. One acceptable method of ensuring that the lines are full is to vent at the high points.

SR 4.5.2.5 - DELETEDVerifying the correct alignment for manual, power operated, and automatic valves in the required ECCS subsystem flow paths provides assurance that the proper flow path will be available for ECCS operation. This SR does not apply to valves that are locked, sealed, or otherwise secured in position, since these valves were verified to be in the correct position prior to locking, sealing, or securing. A valve that receives an initiation signal is allowed to be in a nonaccident position provided the valve will automatically reposition in the proper stroke time. This SR does not require any testing or valve manipulation; rather, it involves verification that those valves capable of potentially being mispositioned are in the correct position. This SR does not apply to valves that cannot be inadvertently misaligned, such as check valves.

SR 4.5.2.6 - Verifying that the required ECCS injection/spray subsystem can be manually aligned, and the pump started and operated for at least 10 minutes demonstrates that the subsystem is available to mitigate a draining event. This surveillance requirement is modified by two footnotes. The first states that tTesting the ECCS injection/spray subsystem may be done through the test return line recirculation full flow test line is necessary to avoid overfilling the

refueling cavity. The second states that credit for meeting the surveillance requirement may be taken for normal system operation that satisfies the surveillance requirement, such as using the RHR mode of LPCI for greater than or equal to 10 minutes. The minimum operating time of 10 minutes was based on engineering judgement.

SR 4.5.2.7 - Verifying that each valve credited for automatically isolating a penetration flow path actuates to the isolation position on an actual or simulated RPV water level isolation signal is required to prevent RPV water inventory from dropping below the TAF should an unexpected draining event occur.

LIMERICK - UNIT 2 B 3/4 5-3e Associated with Amendment No. 190

EMERGENCY CORE COOLING SYSTEM BASES RPV WATER INVENTORY CONTROL (WIC) (Continued)

SR 4.5.2.8 - The required ECCS subsystem is required to actuate on a manual initiation signal. This surveillance verifies that a manual initiation signal will cause the required CSS subsystem or LPCI subsystem can be manually aligned and started from the control room, including any necessary valve alignment, instrumentation, or controls, to transfer water from the suppression pool or CST to the RPV. to start and operate as designed, including pump startup and actuation of all automatic valves to their required positions. This SR is modified by a note that excludes vessel injection/spray during the surveillance. Since all active components are testable and full flow can be demonstrated by recirculation through the test line, coolant injection into the RPV is not required during the surveillance.

The Surveillance Frequencies in the above SRs are controlled under the Surveillance Frequency Controlled Program.

REFERENCES

1. Information Notice 84-81, "Inadvertent Reduction in Primary Coolant Inventory in Boiling Water Reactors During Shutdown and Startup," November 1984.

2. Information Notice 86-74, "Reduction of Reactor Coolant Inventory Because of Misalignment of RHR Valves," August 1986.

3. Generic Letter 92-04, "Resolution of the Issues Related to Reactor Vessel Water Level Instrumentation in BWRs Pursuant to 10 CFR 50.54(f)," August 1992.

4. NRC Bulletin 93-03, "Resolution of Issues Related to Reactor Vessel Water Level Instrumentation in BWRs," May 1993.

5. Information Notice 94-52, "Inadvertent Containment Spray and Reactor Vessel Draindown at Millstone 1," July 1994.

6. General Electric Service Information Letter No. 388, "RHR Valve Misalignment During Shutdown Cooling Operation for BWR 3/4/5/6," February 1983.

LIMERICK - UNIT 2 B 3/4 5-3f Associated with Amendment No. 190

v t e Letter Sequence Request
EPID:L-2020-LLA-0199, TSTF-582 (Approved, Closed)
Initiation Request, Request Acceptance Administration Questions Answers Results Approval Other:
MONTHYEAR2020-09-03 [Table View]

ML20247J372

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Subject:

Enclosure:

1.0 DESCRIPTION

3.0 REGULATORY ANALYSIS

5.0 REFERENCES

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