NMP2L2563, License Amendment Request - Primary Containment Isolation Instrumentation Technical Specification Allowable Value Change

License Amendment Request - Primary Containment Isolation Instrumentation Technical Specification Allowable Value Change

ML14321A744
Person / Time
Site:	Nine Mile Point
Issue date:	11/17/2014
From:	Jim Barstow Exelon Generation Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
NMP2L2563
Download: ML14321A744 (15)

Text

10 CFR 50.90 NMP2L2563 November 17, 2014 U.S. Nuclear Regulatory Commission ATIN: Document Control Desk Washington, DC 20555 Nine Mile Point Nuclear Station, Unit 2 Renewed Facility Operating License No. NPF-69 NRG Docket No. 50-410

Subject:

License Amendment Request - Primary Containment Isolation Instrumentation Technical Specification Allowable Value Change In accordance with 10 CFR 50.90, Exelon Generation Company, LLC (Exelon) requests an amendment to the Technical Specifications, Appendix A, of Renewed Facility Operating License No. NPF-69 for Nine Mile Point Nuclear Station, Unit 2 (NMP2).

The proposed amendment would revise the NMP2 Technical Specification (TS) Allowable Value for the Main Steam Line Tunnel Lead Enclosure Temperature-High instrumentation from an ambient temperature dependent (variable setpoint) to ambient temperature independent (constant Allowable Value). The changes would delete Surveillance Requirement (SR) 3.3.6.1.2 and revise the Allowable Value for Function 1.g on Table 3.3.6.1-1, "Primary Containment Isolation Instrumentation." In addition, the associated Bases will be revised.

The implementation of this amendment will enhance plant operational reliability and reduce risk by minimizing the potential for a plant trip function and/or an unnecessary plant shutdown. In addition, these changes will improve ALARA dose goals and reduce industrial safety risks by minimizing station personnel entries into high-energy steam piping environments. Therefore, Exelon is requesting an expedited review of this submittal in order to support implementation prior to the next seasonal (summer 2015) temperature adjustments. provides the Evaluation of Proposed Technical Specification Changes. provides the Proposed Technical Specification and Bases Marked-Up Pages.

LAR - Primary Containment Isolation Instrumentation Technical Specification Allowable Value Change November 17, 2014 Page 2 The proposed changes have been reviewed by the NMP Plant Operations Review Committee and approved in accordance with Nuclear Safety Review Board procedures.

Exelon requests approval of the proposed amendment by May 15, 2015. Once approved, the amendment shall be implemented within 60 days.

There are no regulatory commitments contained in this request.

In accordance with 10 CFR 50.91, "Notice for public comment; State consultation,"

paragraph (b), Exelon is notifying the State of New York of this application of license amendment by transmitting a copy of this letter and its attachments to the designated State Official.

Should you have any questions concerning this submittal, please contact Ron Reynolds at (610) 765-5247.

I declare under penalty of perjury that the foregoing is true and correct. Executed on the 171h day of November 2014.

Respectfully, James Barstow Director - Licensing & Regulatory Affairs Exelon Generation Company, LLC Attachments: 1) Evaluation of Proposed Technical Specification Changes

2) Proposed Technical Specification and Bases Marked-Up Pages cc: USNRC Regional Administrator, Region I w/attachments USNRC Project Manager, NMP w/attachments USNRC Senior Resident Inspector, NMP w/attachments A. L. Peterson, NYSERDA w/attachments

ATTACHMENT 1 EVALUATION OF PROPOSED TECHNICAL SPECIFICATION CHANGES

SUBJECT:

Primary Containment Isolation Instrumentation Technical Specification Allowable Value Change 1.0

SUMMARY

DESCRIPTION 2.0 DETAILED DESCRIPTION

3.0 TECHNICAL EVALUATION

4.0 REGULA TORY EVALUATION 4.1 Applicable Regulatory Requirements/Criteria 4.2 Precedent 4.3 No Significant Hazards Consideration 4.4 Conclusions

6.0 REFERENCES

Evaluation of Proposed Attachment 1 Technical Specification Changes Page 1of7 Primary Containment Isolation Instrumentation Technical Specification Allowable Value Change 1.0

SUMMARY

DESCRIPTION This evaluation supports a request to amend Renewed Operating License No. NPF-69 for Nine Mile Point Nuclear Station, Unit 2 (NMP2).

The proposed changes would revise the Technical Specification (TS) instrument Allowable Value (AV) associated with the Leak Detection System (LOS) for the Main Steam Line Tunnel Lead Enclosure and delete the associated Surveillance Requirement (SR). This License Amendment Request would change the Main Steam Line Tunnel Lead Enclosure leak detection temperature setpoint from ambient lead enclosure area temperature dependent (i.e., variable AV) to ambient temperature independent (i.e., constant AV). The constant AV would use the upper limit of the variable temperature range currently approved and identified in the TS. This constant setpoint temperature would eliminate future temperature adjustments for winter and summer months in the Main Steam Line Tunnel Lead Enclosure. In addition, the proposed changes would enhance plant operational reliability and reduce risk by minimizing the potential for a plant trip function and/or unnecessary plant shutdown. These proposed changes will improve ALARA dose goals and reduce industrial safety risks by minimizing station personnel entries into high-energy steam piping environments.

Exelon Generation Company, LLC (Exelon) requests approval of the proposed changes. Once approved, the amendment shall be implemented within 60 days.

2.0 DETAILED DESCRIPTION The proposed changes would revise the AV temperature for the Main Steam Line Tunnel Lead Enclosure Temperature - High isolation AV (TS Table 3.3.6.1-1, Function No. 1.g) from ambient temperature dependent (~151.6°F + (0.6)( Tamb- 90°F) provided the absence of steam leaks in the Main Steam Line Tunnel Lead Enclosure area is verified by visual inspection prior to establishing the Allowable Value) to a constant value (~175.6°F) based on the worst case winter operating conditions. The associated leak rate would change from 25 gallon per minute (gpm) to 45 gpm equivalent condensate steam leak as the design basis for the Main Steam Line Tunnel Lead Enclosure. The proposed changes would also delete the SR 3.3.6.1.2 as the seasonal adjustment to the setpoint temperature for the Main Steam Line Tunnel Lead Enclosure would no longer be necessary. Footnote (b) would also be deleted from TS Table 3.3.6.1-1.

With a constant AV, the need to perform LOS temperature adjustments for the summer and again for the winter months would be eliminated. The plant would reduce the potential for a plant trip function and/or unnecessary plant shutdown in order to recalibrate the temperature trip units in the Main Steam Line Tunnel Lead Enclosure associated with the LOS temperature adjustments.

The purpose of the leak detection system instrumentation and controls is to detect and provide the signals necessary to isolate leakage from the reactor coolant pressure boundary before predetermined limits are exceeded.

Evaluation of Proposed Attachment 1 Technical Specification Changes Page 2 of 7 The Main Steam Line Tunnel Lead Enclosure is constantly monitored for leaks by the LOS using dual-element thermocouples for sensing high ambient temperature in the area. If a leak is detected, the detection system responds by triggering an annunciator and initiating a steam line isolation trip logic signal.

This license amendment request only affects the instrument isolation setpoints of the circuits that monitor the ambient temperature and provide system isolations on high ambient temperature for the Main Steam Line Tunnel Lead Enclosure. The LOS is comprised of Temperature Indicating Switches (TIS) that receive data from temperature elements located in the area being monitored and determine if the temperature has reached its isolation setpoints.

If reached, an automatic isolation I alarm signal is initiated and an annunciator is activated in the control room. The TIS setpoints are selected high enough to avoid spurious isolations, yet low enough to provide timely detection of a small leak and isolation at 45 gpm for the Main Steam Line Tunnel Lead Enclosure.

=

Background===

The function of the Main Steam Line Tunnel Lead Enclosure high temperature detection circuitry is to detect a steam leak in the lead enclosure area. The Main Steam Line Tunnel Lead Enclosure has 12 temperature sensors (2MSS*TE69A/B/C/O, 2MSS*TE70A/B/C/O, and 2MSS*TE71 A/B/C/O). These sensors monitor area temperatures at three locations in the lead enclosure, and each location has four sensors. Each sensor has a temperature switch (2MSS*TS1069A/B/C/O, 2MSS*TS1070A/B/C/O, and 2MSS*TS1071A/B/C/O) which actuates when its temperature setpoint is exceeded and closes the Main Steam Isolation Valves (MSIVs).

The MSIVs closure logic is arranged in a "one-out-of-two taken twice" for each location.

In order to maintain sufficient operating margin during the summer season, the setpoints for the Main Steam Line Tunnel Lead Enclosure temperature switches (2MSS*TS1069A/B/C/O, 2MSS*TS1070A/B/C/O, and 2MSS*TS1071A/B/C/O) are seasonally adjusted. This process has the potential to lead to half isolation and possibly a plant shutdown. In addition, it requires increased temperature surveillance to guard against Main Steam Line Tunnel Lead Enclosure temperature reduction.

The existing Analytical Limit (AL) for the lead enclosure LOS varies with the lead enclosure temperatures, from 156 to 180°F. The supporting analysis assumed a 25 gpm (8.35 lbm =

1 gallon) steam leak in the lead enclosure and determined the AL as a function of the initial lead enclosure temperature (90 to 130°F). This approach provided greater operational flexibility.

However, it requires seasonal setpoint adjustments and has the potential for inadvertent MSIV closure and subsequent plant shutdown. The temperature response calculations were performed using the Stone & Webster Engineering Corporation (SWEC) computer code, THREEO Subcompartment Transient Response Code.

Proposed Technical Specification Changes This License Amendment Request would change the Main Steam Line Tunnel Lead Enclosure leak detection temperature setpoint from lead enclosure ambient temperature dependent (AV varies from 151.6 to 175.6°F) to ambient temperature independent (i.e., constant AV). The

Evaluation of Proposed Attachment 1 Technical Specification Changes Page 3 of 7 temperature setpoint would be changed to the maximum currently allowed by the Technical Specifications (Table 3.3.6.1-1, Function 1.g; Allowable Value= s175.6°F). To achieve this change, the leak detection basis requires revision from 25 to 45 gpm (equivalent steam leakage) for the lead enclosure only. Other locations in the main steam tunnel remain capable of detection of a 25 gpm equivalent steam leak.

In addition, the TS SR 3.3.6.1.2, "Verify the actual ambient temperature reading for all OPERABLE channels is ~ Tamb," is deleted.

The specific changes to Technical Specifications and associated Bases are shown on .

Evaluation Setpoint Change:

To support the use of the existing maximum AV of 175.6°F for the Main Steam Line Tunnel Lead Enclosure temperature, the existing design basis model and assumptions are used in the revised analysis. The lead enclosure temperature response is calculated using GOTHIC computer code (version 8.0).

The existing design basis model used the SWEC THREED computer code. The GOTHIC model is benchmarked against the TH REED code by reproducing the temperature transients for a 25 gpm equivalent steam leak. It is concluded that the GOTHIC model and methods as implemented result in essentially the same temperatures (i.e., within 2°F) as the THREED model used by SWEC for the original temperature response calculations. Using this GOTHIC model, the steam leakage that results in AL of 180°F corresponding to 175.6°F AV is defined.

Using the most limiting winter conditions (same as those assumed in the existing analysis), the leak rate corresponding to 180°F AL is a 45 gpm steam leak.

Table 1 lists the parameters before and after the proposed amendment. The setpoint methodology remains the same as the current setpoint methodology. As seen in Table 1, the proposed setpoints (AL, AV, and TSP) are the same as those currently allowed by the existing setpoint calculation and the current Technical Specification.

Table 1 Current Value vs. Proposed Change for Specific Parameters Parameter Before Proposed Change After Proposed Change Analytical Limit 156 - 180°F 180°F Allowable Value 151.6- 175.6°F 175.6°F Trip Set Point (Upper) 148.2 172.2°F 172.2°F Leak Rate 25aom 45qpm The proposed change is not expected to reduce operating temperature margin during the summer season because the above values have been proved satisfactory.

Critical Crack Size:

The critical crack size leak rate is described in USAA Section 5.2.5.5.3. Each Main Steam Line in the lead enclosure is 28 inch OD carbon steel pipe (A 106 Gr C) with 1.339 inch nominal wall thickness. Using the same approach described in USAA Section 5.2.5.5.3, the longitudinal

Evaluation of Proposed Attachment 1 Technical Specification Changes Page 4 of 7 critical crack is approximately 37 inches. The corresponding leak rate is estimated to be greater than 450 gpm, or 10 times the leak rate used for the leak detection setpoint. Based on the above, it is concluded that the LDS will isolate the MSL with adequate margin for contingencies, regarding a crack size large enough to propagate rapidly.

Radiological Impact:

The increase in the steam leak rate has no impact on the radiological consequences associated with the Main Steam Line Break (MSLB} described in USAR Section 15.6.4, Steam System Piping Break Outside Containment. The radiological consequences (using the same source terms and dispersion factors used for the MSLB} associated with the 45 gpm steam leak for one hour is bounded by the MSLB described in USAR Section 15.6.4.

Eguipment Qualification and Structural Impact The peak temperatures associated with a 25 or 45 gpm equivalent steam leak are essentially the same, 180°F. The maximum temperature in the lead enclosure is established by the MSLB.

Therefore, there is no adverse impact on the SSCs located in the steam tunnel.

Impact of TS SR 3.3.6.1.2 Deletion:

The new AV, 175.6°F, is based on the worst case winter condition. The initial lead enclosure ambient temperature assumed in the analysis is 80°F, well below the typical winter or summer time operating temperature in the lead enclosure. Typical winter time operating temperature in the lead enclosure ranges from 100 to 115°F. The lowest recorded temperature between 2009 and 2014 is 95°F for a period of approximately two days. Thus, the new AV is based on sufficiently low ambient temperature. Therefore, periodic surveillance is not required consistent with the existing TS SR 3.3.6.1.2 Bases.

4.0 REGULATORY EVALUATION

4.1 Applicable Regulatory Requirements/Criteria The proposed changes have been evaluated to determine whether applicable regulations and requirements continue to be met. Exelon Generation Company, LLC (Exelon) has determined that the proposed changes do not require any exemptions or relief from regulatory requirements other than the TSs. The following applicable regulations and regulatory requirements were reviewed in making this determination:

10 CFR 50 Appendix A, General Design Criterion (GDC) 13, "Instrumentation and control,"

requires, in part, that instrumentation be provided to monitor variables and systems, and that controls are provided to maintain these variables and systems within prescribed operating ranges.

10 CFR 50 Appendix A, GDC 20, "Protection system functions," requires, in part, that the protection system be designed to initiate automatically the operation of appropriate systems, including the reactivity control systems, to assure that specified acceptable fuel design limits are not exceeded as a result of anticipated operational occurrences.

Evaluation of Proposed Attachment 1 Technical Specification Changes Page 5of7 10 CFR 50 Appendix A, GDC 30, "Quality of reactor coolant pressure boundary," requires, in part, that means shall be provided for detecting and, to the extent practical, identifying the location of the source of reactor coolant leakage.

Regulatory Guide 1.105, Revision "Instrument Setpoints for Safety-Related Systems,"

describes a method acceptable to the NRC staff for complying with the NRC's regulations for ensuring that setpoints for safety-related instrumentation are initially within and remain within the TS limits.

The NMP2 design complies with the Regulatory Position (Paragraph C) of this guide. NMP2 USAA Table 1.8-1 states:

"The Unit 2 project complies with the Regulatory Position (Paragraph C) of this guide."

NMP2 USAA Section 7.1.2.3 states, in part:

"The trip setpoint (instrument setpoint) and allowable value (Technical Specification limit) are contained in Technical Specifications. These parameters are all appropriately separated from each other and their selection is based on instrument accuracy, calibration capability, and design drift (estimated) allowance data. The setpoints are within the instrument accuracy range. The established setpoints provide margin to satisfy both safety requirements and plant availability objectives."

4.2 Precedent A 1992 Susquehanna License Amendment (Reference 1) was approved for the Leak Detection Function in the Turbine Building Main Steam Tunnel that changed the leakage basis from a 25 gpm leak to a 65 gpm equivalent leak during winter operations. This amendment revised the isolation setpoint from 117°F to 197°F.

A 1996 LaSalle License Amendment (Reference 2) was approved for changes to setpoints for the automatic primary containment isolation on the Main Steam Line Tunnel which changed the leakage basis from 25 gpm to 100 gpm. The amendment revised the Main Steam Tunnel Differential-High isolation signal from s36°F to S65°F.

A 2004 Perry License Amendment (Reference 3) was approved for changes to the Primary Containment and Drywell Isolation Instrumentation to increase the analytical limit for detected temperature resulting in a change to the AV related to the setpoint for the Main steam Line Turbine Building temperature-High system isolation function from 138.9 °F to 149.6°F. This temperature increase corresponds to an increase in the LOS upper boundary leakage limit from an equivalent steam leakage value of 25 gpm to 280 gpm.

4.3 No Significant Hazards Consideration Exelon has evaluated whether or not a significant hazards consideration is involved with the proposed amendment by focusing on the three standards set forth in 10 CFR 50.92, "Issuance of amendment," as discussed below:

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

Response: No.

Evaluation of Proposed Attachment 1 Technical Specification Changes Page 6 of 7 The proposed changes do not involve a significant increase in the probability or consequences of an accident previously evaluated because the performance of any equipment credited in the radiological consequences of an accident is not affected by the change in the leak detection capability.

The Main Steam Line Tunnel Lead Enclosure Temperature - High is provided to detect a steam leak in the lead enclosure and provides diversity to the high flow instrumentation. This function provides a mitigating action for a steam leak in the Main Steam Line Tunnel Lead Enclosure, which could lead to a pipe break. This function does not affect any accident precursors, and the proposed changes do not affect the leak detection capability. Additionally, the proposed changes do not degrade the performance of or increase the challenges to any safety systems assumed to function in the accident analysis.

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

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

Response: No.

The proposed changes do not create the possibility of a new or different kind of accident from any accident previously evaluated because the proposed changes do not add or remove equipment and do not physically alter the isolation instrumentation. In addition, the Main Steam Line Tunnel Lead Enclosure LOS is not utilized in a different manner.

The proposed changes do not introduce any new accident initiators and new failure modes, nor do they reduce or adversely affect the capabilities of any plant structure, system, or component to perform their safety function. The Main Steam Line Tunnel Lead Enclosure LOS will continue to be operated in the same manner.

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

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

Response: No.

The proposed changes do not involve a significant reduction in a margin of safety because the changes eliminate the temperature setpoint dependency on lead enclosure temperature while maintaining the existing upper AV = 175.6°F, that was previously evaluated and approved. There is no adverse impact on the existing equipment capability as well as associated structures. The increase in the steam leak rate and associated crack size continues to be well below the leak rate associated with critical crack size that leads to pipe break. The proposed changes continue to provide the same level of protection against a main steam line break as the existing setpoint values.

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

Evaluation of Proposed Attachment 1 Technical Specification Changes Page 7of7 Based on the above, Exelon concludes that the proposed amendment does not involve a 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.

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

5.0 ENVIRONMENTAL CONSIDERATION

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

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

6.0 REFERENCES

1. Isolation Setpoint for the Leak Detection Temperature Function in the Turbine Building Main Steam Tunnel, Susquehanna Steam Electric Station, Units 1 and 2 (TAC NOS. M80222 and M80223), dated May 21, 1992

2. Issuance of Amendments (TAC NOS. M94583 and M94779), dated April 4, 1996 (ML021130125) (LaSalle County, Units 1 and 2)

3. Perry Nuclear Power Plant, Unit 1 - Issuance of Amendment (TAC NO. MC0342),

dated July 9, 2004 (ML041810686)

ATTACHMENT 2 PROPOSED TECHNICAL SPECIFICATION and BASES MARKED-UP PAGES (Unit 2)

TS Pages 3.3.6.1-4 and -6 Bases Pages B3.3.6.1-12 and -35

Primary Containment Isolation Instrumentation 3.3.6.1 SURVEILLANCE REQUIREMENTS

1. Refer ta Table 3.3.6.1-1 ta determine which SRs apply far each Primary Containment Isolation Function.

2. When a channel is placed in an inoperable status solely far performance of required Surveillances, entry into associated Conditions and Required Actions may be delayed far up to 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> provided the associated Function maintains isolation capability.

SURVEILLANCE FREQUENCY SR 3.3.6.1.1 Perform CHANNEL CHECK. 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> SR 3.3.6.1.2 Only required to be met *11hon tho

/\,llowable Value is adjusted in aocordanoe with Table 3.3.6.1 1, footnote (b).

12 ROUFS SR 3.3.6.1.3 Perform CHANNEL FUNCTIONAL TEST. 92 days SR 3.3.6.1.4 Calibrate the trip unit. 92 days SR 3.3.6.1.5 Perform CHANNEL CALIBRATION. 24 months SR 3.3.6.1.6 Perform LOGIC SYSTEM FUNCTIONAL TEST. 24 months (continued)

NMP2 3.3.6.1-4 Amendment 91

Primary Containment Isolation Instrumentation 3.3.6.1 Table3.3.6.1*1(page1 of5)

Primary Containment Isolation Instrumentation MODES OR REQUIRED REFERENCED OTHER CHANNELS FROM SPECIFIED PER TRIP REQUIRED SURVEILLANCE ALLOWABLE

1. Main Steam Line Isolation

a. Reactor Vessel Water 1,2,3 2 D SR 3.3.6.1.1 10.8 Inches Level Low Low Low, SR 3.3.6.1.3 Level 1 SR 3.3.6.1.4 SR 3.3.6.1.5 SR 3.3.6.1.6 SR 3.3.6.1.7

b. Main Steam Line Pressure 2 E SR 3.3.6.1.1 746 psig Low SR 3.3.6.1.3 SR 3.3.6.1.4 SR 3.3.6.1.5 SR 3.3.6.1.6 SR 3.3.6.1.7

c. Main Steam Line 1,2,3 2 per MSL D SR 3.3.6.1.1 ,:; 184.4 psid Flow High SR 3.3.6.1.3 SR 3.3.6.1.4 SR 3.3.6.1.5 SR 3.3.6.1.6 SR 3.3.6.1.7

d. Condenser Vacuum - Low 1,2(a), 2 D SR 3.3.6.1.1 7.6 Inches SR 3.3.6.1.3 Hg vacuum 3(a) SR 3.3.6.1.4 SR 3.3.6.1.5 SR 3.3.6.1.6

e. Main Steam Line 1,2,3 2 D SR 3.3.6.1.1 ,:; 170.6°F Tunnel SR 3.3.6.1.3 Temperature - High SR 3.3.6.1.5 SR 3.3.6.1.6

f. Main Steam Line 1,2,3 2 D SR 3.3.6.1.1 71.7°F Tunnel Differential SR 3.3.6.1.3 Temperature - High SR 3.3.6.1.5 SR 3.3.6.1.6

g. Main Steam Line 1,2,3 2 per area D SR 3.3.6.1.1 Tunnel Lead Enclosure SR 3.3.6A.2 Temperature - High SR 3.3.6.1.3 SR 3.3.6.1.5 SR 3.3.6.1.6

h. Manual Initiation 1,2,3 4 G SR 3.3.6.1.6 NA (a) With any turbine stop valve not closed.

fb1 451.6°F + \0.e)(Tamo 90°F) and<< 175.6°F pF<wided the absenoe of steam leaks in the main oleam line tunnel lead en~ed by 'lisual lnspeetien prier te estabiisll~llewable \lalue.

NMP2 3.3.6.1-6 Amendment 94, 140

Primary Containment Isolation Instrumentation B 3.3.6.1 BASES APPLICABLE 1.g. Main Steam Line Tunnel Lead Enclosure SAFETY ANALYSES, Temperature - High (continued)

LCO, and APPLICABILITY occurs when a very small leak has occurred in any one of the three areas of the enclosure. If the small leak is allowed to continue without isolation, offsite dose limits may be reached. However, credit for these instruments is not taken in any transient or accident analysis in the USAR, since bounding analyses are performed for large breaks such as MSL breaks.

Main Steam Line Tunnel Lead Enclosure Temperature - High signals are initiated from thermocouples located in the area being monitored. Twelve channels of Main Steam Line Tunnel Lead Enclosure Temperature - High Function are available and are required to be OPERABLE (four in each of the three areas) to ensure that no single instrument failure can preclude the isolation function.

The Main Steam Line Tunnel Lead Enclosure Temperature - High Allowable Value is chosen to detect a leak equivalent to

~ gpm. In addition, as ambient temperature in the main steam line tunnel lead enclosure inereases, the Allowable Value is allowed to be inoreased as described in footnote (b) to Table 3.3.6.1 1. This is permitted pre*1ided the main steam line tunnel lead enclosure is visually inspected to ensure the ambient temperature increase is not due to a steam leak.

This Function isolates the Group 1 valves.

1.h. Manual Initiation The Manual Initiation switch and push button channels introduce signals into the MSL isolation logic that are redundant to the automatic protective instrumentation and provide manual isolation capability. There is no specific USAR safety analysis that takes credit for this Function.

It is retained for overall redundancy and diversity of the isolation function as required by the NRC in the plant licensing basis.

There are four switch and push buttons (with two channels per switch and push button) for the logic, with two switch and push buttons per trip system. Eight channels of Manual (continued)

NMP2 B 3.3.6.1-12 Revision O

Primary Containment Isolation Instrumentation B 3.3.6.1 BASES SURVEILLANCE SR REQUIREMENTS (continued) This SuA<eillanoe erifies that, when the Allowable \lalue for Ina Main Steam bine +unnel bead Enclosure Tumperature Migl=! Funotien is adjusted based on the formula in footnate (b) te Tuble 3.3.6.1 1, the aotual ambient temperature, as measured by the Main Stearn line Tunnel bead enolesure +emperatt:tre High Funotion channels, is greateF thaR or eetual te the ambient tempeFature (1'am11) used te adjust the Allw.vable \lalue. Only the OPERABLE Main Steam line l'unnel bead Enolosure +ernperature High Funotion ohannels are reetuired te be 'Jerified. As stated in the Note te tne 8R, the 8R is only reetuired to be met 'Nhen the Allowable Value is adjusted in aooordanoe 'Nith Tuble 3.3.6.1 1, footnote (b), since the normal Allo'l.<able Value is based on a su#ioieAtiy loi.*.i ambient temperature that the ¥erifioation is net neoessary.

The Freetuenoy of 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> is based on the need te periodioally monitor the ambient temperature to eAsure the Allov.'able Vah:1e remains valid, and \*.*as ohoseA to seineide with the GMANNEL GMEGK Freetuensy. ,A,s requireEI by SR 3.0A, the SR must alse be performeEI prior to adjusting the AllO\\table Value, sinoe the SuNeillanoe must be met at all times when the Allo*1.<able Value has beeA aEljusted (thus te rneet the SR when the Allo*.-..able value has been adjusted, it must aetually be performeEI prior to the adjustment).

SR 3.3.6.1.3 A CHANNEL FUNCTIONAL TEST is performed on each required channel to ensure that the channel will perform the intended function. Any setpoint adjustment shall be consistent with the assumptions of the current plant specific setpoint methodology.

The Frequency of 92 days is based on reliability analyses described in References 11 and 12.

SR 3.3.6.1.4 The calibration of trip units consists of a test to provide a check of the actual trip setpoints. The channel must be declared inoperable if the trip setting is discovered to be less conservative than the Allowable Value specified in (continued)

NMP2 B 3.3.6.1-35 Revision 0