ML18022A811

Proposed Tech Specs Re RHR Auto Closure Interlock Deletion

ML18022A811
Person / Time
Site:	Harris
Issue date:	11/16/1990
From:	CAROLINA POWER & LIGHT CO.
To:
Shared Package
ML18009A731	List: ML18009A730 ML18022A811
References
NUDOCS 9011270005
Download: ML18022A811 (31)

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ENCLOSURE 4 SHEARON HARRIS NUCLEAR POWER PLANT DOCKET NO.50-400/LICENSE NO.NPF-63 REQUEST FOR LICENSE AMENDMENT TECHNICAL SPECIFICATION PAGES 90ii270005 90lli6 PDR ADOCK 05000400 P PDC EMERGENCY CORE COOLING SYSTEMS 3/4e 5e 2 ECCS SUBSYSTEMS T GREATER THAN OR EQUAL TO 350 F LIMITING CONDITION FOR OPERATION 3.5.2 Two independent Emergency Core Cooling System (ECCS)subsystems shall be OPERABLE with each subsystem comprised of: a.One OPERA8LEjharging/safety injection pump, b.One OPERABLE RHR heat exchanger, c.One OPERABLE RHR pump, and d.An OPERABLE flow path capable of taking suction from the refueling water storage tank on a Safety Injection signal and, upon being manually aligned, transferring suction to the containment sump during the recirculation phase of operation.

APPLICABILITY:

MODES 1, 2, and 3.ACTION: a.b.With one ECCS subsystem inoperable, restore the inoperable subsystem to OPERABLE status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> or be in at least HOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />'nd in HOT SHUTDOWN within the following 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.In the event the ECCS is actuated and injects water into the Reactor Coolant System, a Special Report shall be prepared and submitted to the Commission pursuant to Specification 6.9.2 within 90 days describ-ing the circumstances of the actuation and the total accumulated actuation cycles to date.The current value of the usage factor for each affected Safety Injection nozzle shall be provided in this Special Report whenever its value exceeds 0.70.SURVEILLANCE RE UIREMENTS 4.5.2 Each ECCS subsystem shall be demonstrated OPERABLE: a.At least once er 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> b verifying that the following valves are.in the indicated osstsons with ower to the valve o ra removed: ye,riFv;nn pro,~We lotto<<g valvea art.'n+<i~dlc4ded posiAoA5~I the con~o~power discQnneck sluiteh in the"DF~"Po~+i<<8 Qnd 41m'~lVC CD'rOl~upi+&irl+e."PMl.L I l.OQg")oSi tiOn'-SHEARON HARRIS-UNIT 1 3/4 5"3 EMERGENCY CORE COOLING SYSTEMS t SURVEILLANCE RE UIREMENTS Continued)

CP&L Valve Ho.1SI-1O7 Dl-86 1SI-52 1SI-340 EBASCO Valve No.2SI-VSOOSA-1 2SI-V501S8-1 2SI-V502SA-1 25 I-V579SA-1 Valve Function High Head Safety Injection to Reactor Coolant System Hot Legs High Head Safety Injection to Reactor Coolant System Hot Legs High Head Safety Injection to Reactor Coolant System Cold Legs Low Head Safety Injection to Reactor Coolant System Cold Legs Valve Position CIased(11 Closed 1 Close 1 Open 1SI-341 2SI-V578SB-1 Low Head Safety Injection to Open 1 Reactor Coolant System Cold Legs 1SI-359 25 I-V587SA-1 Low Head Safety Injection to Reactor Coolant System Hot Legs Close 1 b.At least once per 31 days by: 1.Verifying that the ECCS piping is full of water by venting accessible discharge piping high points, and 2.Verifying that each valve (manual, power operatid, or automatic) in the.flow path that is not locked, sealed, or otherwise secured in position, is in its correct position.C.By a visual inspection which verifies that no loose debris (rags, trash, clothing, etc.)is present in the containment which could be transported to the containment sump and cause restriction of the pump suctions during LOCA conditions.

'his visual inspection shall be performed:

1.For all accessible areas of the containment prior to establish-ing CONTAINMENT INTEGRITY, and 2.Of the areas affected within containment at the completion of'ach containment entry when CONTAINMENT INTEGRITY is established.--"Closed-1 and Open-I.-The Control Power Oisconnect S~itch shall be maintained in the"OFF" positioii and the valve control switch shall be maintained in the valve position noted above.SHEARON HARRIS UNIT 1 3/4 5-4 EMERGENCY CORE CQDLENG SYSTEMS SURVEILLANCE RE UERBIENTS Continued d.At least once per 18 months by: l.'erffyfng automatic isolation an fnterlock action of the RHR system from the Reactor oo ant System hy ensuring the~a)pith a simulated or actual Reactor Coolant System pressure signal greater than or equal to 425 psi th interlocks prevent the valves.from being opened and h)Nth a simulated or actual Reactor Coolant System pressure signal less than or equal to 750 psig the interlocks will cause the valves to automatfcally close.OC 2.A visual fnspection of containment sump and verifying that the subsystem suction in ets are not restricted by debris and that the sump components (trash racks, screens, etc.)show no evidence of structuraI distress or abnormaI corrosion.

e.At least once per 18 months, during shutdown, by: l.Verifying that each automatic valve in the flow path actuates to its cor rect position on saf'ety injectfon actuation test signal and on safety injection switchover to contaf'nment sump from an EST Lo-Lo level test signal, and'.Verffyfng that each of the following pumps start automatically upon receipt of a safety fnjectfon actuation test signaI: a)barging/satety infection pump.b)RHR pump.By veri fyfng that each of the following pumps develops the required df fferentfaI pressure when tested pursuant to Specification 4.0.5: l.charging/safety infection pump (Rarer to Speci tication a.l.Z.S)=2.RHR pump>104 psid at a flow rate of at least 3663 gpm.g.By verifying that the locking mechanism is in place and locked for the fo11owf ng rottle valves: gy Head 1.Nthfn 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> following completion of each valve stroking-operation or maintenance on the valve when the ECCS subsystems are required to be OPERABLE, and 2.At least once per M months.SHEARON HARRIS-ND 1 3/4 5-5 EHERQENCY CORE COOLING SYSTEMS SURVEILLANCE RE UIREMENTS Continued HPSI SYSTEM EBASCO Va ve No.K=-ZSI-V4395B-1 2SI-V43BSA-1 2SI-V4375A-1 2SI-V43658-1 2SI-V4355A-1 2SI-V4345A-1 25 I-V43358-1 25l-V432SA-1 2SI-V431SA-1 2SI-V43058 1 25 I-V429SA-1 H T CP&L Valve No.15I-6'SI-7 1SI-69 ZSI-70 1SI-71 1SI-101 15l-102 1SI 103 1SI-?24 1SI-125 1SI-126 h.By performing a flow balance test, during shutdown, following com-pletion of modifications to the ECCS subsystems that alter the subsystem flow characteristics and verifying that: 1.Far/harping/safaty injantinn pump 1inas, with a singis pump running: a)The sum of the infection l.ine flow rates, excluding the highest flow rate, is greater than or equal to 379 gpm, and b)The total pump flow rate is less than or equal to 685 2.For RHR pump lines, with a single pump running, the sum of the infection line flow rates is greater than or equal to 3663 gpm.SHEARON HARRIS-UNIT 1 3/4 5 6 ENCLOSURE 5 SHEARON HARRIS NUCLEAR POWER PLANT DOCKET NO.50-400/LICENSE NO.NPF-63 REQUEST FOR LICENSE AMENDMENT ATTACHMENT SHNPP Plant S ecific Com arison to WCAP-11 36 and Five S ecific Plant Im rovements Re uired B The NRC SER on WCAP-ll 36-A SHNPP Plant S ecific Com arison to WCAP-11736-A The Shearon Harris plant design currently utilizes a Residual Heat Removal Autoclosure Interlock feature (RHR ACI)to automatically close the RHR suction isolation valves during plant operations, should the RCS pressure increase sufficiently without operator intervention.

The current RHR ACI setpoint is 700 psig.This interlock is subject to surveillance testing as required by Technical Specification 4.5.2.d.l.(b).

The purpose of this Technical Specification change request is to delete this surveillance testing since it is proposed to delete the RHR ACI feature.The deletion of the RHR ACI for a Westinghouse design PWR was granted for the Diablo Canyon plant in February 1988.Subsequently, Westinghouse Electric Corporation, for the Westinghouse Owners Group (WOG), was contracted to provide a generic report that evaluated the removal of the RHR ACI.Westinghouse produced WCAP-11736 which documents, for four Westinghouse reference plants, the review and analysis that was performed to justify the deletion of the autoclosure interlock associated with the residual heat removal system suction/isolation valves.The reference plants represent the lead plant in each of four groups into which participating Westinghouse plants were categorized.

This report was reviewed by the NRC and found to provide an acceptable basis for removal of the RHR ACI.The NRC staff Safety Evaluation Report (SER)(Reference 2)also accepted the use of the WCAP as a reference in subsequent Westinghouse plant submittals proposing RHR ACI deletion provided that five specific plant improvements are included.The NRC's SER, dated August 8, 1989, has been incorporated into the WCAP which was republished as WCAP-11736-A.(Reference 1)WCAP-11736-A provides the literature review, licensing basis, PRA analysis and data base that may be used by reference as a basis for plant specific proposals to delete the RHR ACI.In order to rely on the lead plant analysis, plant specific submittals must provide a comparison of themselves to the reference plant analysis in order to show applicability.

Section 10 of the WCAP provides a common format for documenting the comparisons.

Any differences that adversely impact the results of the probabilistic analyses require supplemental analysis and/or quantification.

The Shearon Harris Nuclear Power Plant (SHNPP)was selected as the lead plant for Group 4.For this reason WCAP-11736-A provides the underlying basis for the proposed RHR ACI deletion at SHNPP.Therefore, a separate plant-specific analysis for RHR ACI deletion at SHNPP is not required.However, in the discussion that follows, a comparison will be made and the impact discussed where SHNPP's proposed changes, plant configuration or assumptions differ with the statements made in the WCAP.Where differences exist in the plant configuration, assumptions, or proposed changes, they have been examined to verify that they do not negatively E5-1 affect the conclusions reached in the WCAP.As a result, the basis and conclusions reached in WCAP-11736-A are applicable to the proposed modifications at the Shearon Harris Nuclear Power Plant.The discussion below is formatted to address the items identified in Section 10.0 of the WCAP,regarding report documentation.

Following the comparison, the five specific plant improvements cited in the SER are addressed."Description of the differences between the plant and the reference plant in the generic portion." Since SHNPP was selected as a lead for Group 4, the description provided in Section 5.4 represents the actual plant configuration, except for the following minor items: In Figure 5-18, there are additional relief valves (one per suction loop)located between the two RHR suction isolation valves.The function of these relief valves is to protect against overpressurization of the piping due to any RCS back leakage or thermal expansion of water trapped between the normally closed suction isolation valves.Since that portion of the piping is designed for 2485 psig, these relief valves are also set for 2485 psig.In essence, these relief valves form part of the high-pressure boundary between the suction isolation valves and do not impact the analysis relating to the low-pressure RHR piping.Refer to the attached marked-up Figure 5-18.The heat exchanger flow control valves, 1RH-30 and 1RH-66, are depicted incorrectly on Figure 5-18 as FO/NC.They are actually FO/NO (fail open/normally open), as discussed in Section 5.4.2, page 5-60.This does not impact the analysis.(iii)Miscellaneous vent, drain, and test line connections were omitted from Figure 5-18 for clarity, as they do not functionally impact the PRA analysis.(iv)Section 5.4.3.2 discusses the RHR suction isolation valves and the RCS pressure control loop, in particular, on pages 5-70 and 5-71.The open permissive interlock comparator (A)output state is erroneously described.

It is correctly described on the mark-up pages provided in this enclosure.

This error does not impact the PRA model results.E5-2 (v)Figure 5-19, Sh.2, incorrectly describes Switch SW¹1 as a torque switch whereas, in reality, it is a limit switch on a Limitorque actuator.Since this performs the same function, it does not change the analysis.See marked up Figure 5-19.(vi)Figures 5-20, 5-21, 5-22, and 5-23 erroneously describe the K734 contact closure for the open permissive interlock (OPI)as 425 psig, whereas the actual setpoint is 363 psig, as noted in Section 5.4.3.See the attached mark-up of Figure 5-20 (typical).

The actual OPI setpoint of 363 psig is less than the 425 psig stated on Figure 5-20, etc., and in Technical Specification 4.5.2.d.l.(a) to allow for elevation differences between the pressure transmitters and the components of the RHR loop, instrument inaccuracies, and relief valve setpoint accuracy.This does not affect the analysis because the OPI and its setpoint is not being modified.These diagrams also contain some minor tag number discrepancies which do not affect the analysis 2."Summary of potential initiating overpressurization transients." Section 7.5'and Appendix D2 of the WCAP describes potential initiating overpressure transients applicable to SHNPP.It is noted that the case of a mass input for the overpressurization analysis is conservative in that two safety injection pumps inadvertently actuated are considered in the analysis whereas, at SHNPP, only one SI pump is permitted to be operable below the Low Temperature Overpressure Protection System (LTOP)enable temperature by Technical Specifications 3.5.3 and 3.1.2.3.3."Quantification of initiating frequencies for overpressurization transients." There are relatively few known overpressurization transients that have actually occurred at SHNPP (example, letdown isolation).

Thus, Table 7-4 clearly bounds the events for SHNPP.The initiating frequency is discussed in Section 7.5.1 and Appendix D2 of the WCAP.4,"Critical assumptions used in analysis." The bounding assumptions for the overpressurization analysis, as documented in Section 7.5 and Appendices D3 and D3.4, were reviewed and found to be conservatively bounding for SHNPP.However, it is noted that in Appendix D.3.4 that the SHNPP maximum charging/safety injection pump flowrate is described as 650 gpm, whereas Technical Specification E5-3 4.5.2.h.l.b allows a maximum pump flowrate of 685 gpm.This does not affect the PRA for overpressurization, since the RHR relief valve capacity is in excess of the maximum charging/S.I.

pump flowrate as allowed by technical specifications.

Also, the description of the Cold Overpressure Protection System (COPS)(referred to as LTOPS at SHNPP)operation has minor discrepancies in that the enable temperature will be 325 F versus 335'F as stated, and the lowest COPS setpoint is 370 psig versus 390 psig as stated.These minor discrepancies do not affect the results of the PRA or the conclusions stated.5."Data used for all calculations." Since SHNPP was a lead plant for Group 4, the calculations presented in the WCAP are applicable for SHNPP.6."Overpressurization event tree modeling with and without autoclosure feature." Since SHNPP was a lead plant for Group 4, the overpressurization event tree was modelled as described in Sections 7.5, Appendix A, Dl, D2, and D.3.4.7."Results of overpressurization event tree quantification." The results of the SHNPP overpressurization event tree quantification are presented in Appendix D.3.4 and Tables D-24, D-25, and D-26 of the WCAP.Although there are some minor discrepancies in the event tree modelling, these do not significantly impact the results of the analysis or the conclusions stated in the report.8."Results of interfacing systems LOCA assessment." The results of the SHNPP interfacing systems LOCA assessment are presented in Table 7-2 and Appendix B-4 of WCAP-11736-A.

Although there are some minor discrepancies in the event tree modelling, these do not significantly impact the results of the analysis or the conclusions stated in the report.There is also a minor typographical error in that Figure B-17 upper cutset¹20 is labeled as"operator fails to close and autoclosure fails", whereas cutset¹20 is only for"operator fails to close".As noted in the title block of Figure B-17, this event tree is for the case without autoclose interlock.

Hence, there is no PRA impact.9."Results of the evaluation on RHR system availability." The results of the SHNPP RHR system (un)availability assessment are presented in Table 7-3 and Appendix C.3.4.Although there are some minor discrepancies in the event tree modelling, these do not significantly impact the E5-4 results of the analysis or the conclusions stated in the report.10."Recommendations concerning removal of the RHRS autoclosure feature." As noted in the Executive Summary Section, the deletion of the autoclosure interlock is recommended for all WOG plants.Carolina Power&Light Company concurs with this recommendation for the Shearon Harris plant.The net effect of deleting the ACI feature and ensuring that operator action based on indications and alarms mitigates the consequences of an overpressure event is considered to be a net improvement in plant safety.11."Recommended logic changes and additions." CP6L concurs in principle with the recommended logic changes and additions identified in Section 6.4 for SHNPP, except as noted below.The exceptions discussed below provide an alternate method of implementing the WOG recommendations and effectively accomplish the same purpose.WCAP-11736-A describes the use of a separate valve stem-mounted limit switch (SMLS)to interlock with the high RCS pressure K735 contacts to provide alarm annunciation on"high RCS pressure-valve not closed" (See Section 6.4 and Figures 6-17 thru 6-21).CPGL proposes to use the existing Limitorque limit switches for position indication in conjunction with the K735 contacts to provide alarm annunciation.

The existing switches provide direct valve position indication and will be verified to change state at full travel.Additionally, the existing indicator lights and the new alarm annunciation would be powered from the same safety train electrical power as for the valve motor, but with the power taken ahead of the valve motor circuit breaker as depicted in Figure 6-18.Hence,"racking out" or opening the valve motor circuit breaker will not affect the power supply availability to the indicator switches or the alarm.The power supply arrangement is permissible, as discussed in Section 6.4.Attached are mark-ups of Figures 6-17 and 6-18 (typical)of the proposed CPBL wiring modifications.

It should be noted that the alarm will be driven from a time-delay relay which is not discussed in the WOG report.The purpose of the time-delay relay (in the range of 0-15 seconds)is to avoid alarm annunciation for expected RCS pressure perturbations, such as the start up of a reactor coolant pump.However, on a sustained high RCS pressure and isolation valves not closed, the alarm will annunciate.

E5-5 These changes do not affect the functional intent of Section 6.4.Also, it does not affect the conclusions of the PRA studies discussed in the WCAP.This method is advantageous to SHNPP because, in addition to the alarm function, it also provides the Control Room operators with valve position status (red/green lights)when the valve motor circuit breaker is racked out during plant normal power operation.

It also avoids the costly and time consuming effect of installing new SMLS and cables and reduces the radiation exposure to workers installing the required modifications.

12."Results of the verification regarding the adequacy of the RHR relief valve to mitigate overpressure transients." Section 9.0 of WCAP-11736-A addresses, among several items, the adequacy of the RHRS relief capacity.For SHNPP, each RHR relief valve is designed to accommodate the combined flow of 3 charging pumps in that mode of operation.

However, the charging pump also serves as the high head safety injection pump.The maximum pump flowrate in the safety injection mode of operation is 685 gpm, as permitted by Technical Specification 4.5.2.h.l.b.

Hence, the maximum pump flowrate in the SI system alignment at the RHR relief valve accumulation pressure of 495 psig, is less than 685 gpm.The RHR relief valve capacity stated in the report for SHNPP is 900 gpm at the RHR relief valve accumulation pressure of 495 psig and a PRT (pressurizer relief tank)backpressure of 50 psig.At a PRT backpressure of 100 psig (the PRT rupture disc setting), the RHR relief valve capacity is less than 900 gpm but greater than the SI pump flowrate at the relief valve accumulation pressure of 495 psig.Therefore, the relief valve is adequately sized to handle an inadvertent safety injection pump start.As restricted by Technical Specifications 3.5.3 and 3.1.2.3, only one charging/safety injection pump is to be operable below the LTOP enable temperature.

13."Written documentation that will ensure the open permissive circuitry is neither removed or affected by the proposed change and that isolation valve position indication will remain available in the Control Room." The open permissive interlock circuitry will not be modified or affected by the proposed changes.Also, as noted in Item 11 above, the isolation valve position indication will be available in the Control Room during all modes of plant operation.

E5-6 14."Responses to the seven NRC issues mentioned earlier in this report and Reference 6 (of the report)." These seven issues are addressed in Section 9.0 of WCAP-11736-A.

Since SHNPP was a lead plant for Group 4 in this report, the discussion in Section 9.0 is directly applicable, except as noted in this submittal.

15."Revised technical specifications." The affected portion of SHNPP Technical Specifications, by this proposed modification, is the Surveillance Requirement 4.5.2.d.l regarding the autoclosure interlock testing.The intent of this surveillance requirement is, in part, to demonstrate ECCS operability for Modes 1, 2, and 3.No other SHNPP Technical Specification is affected by this proposed change.The SHNPP Low Temperature Overpressure Protection System does not take credit for the use of RHR suction relief valves in the LTOP analysis and it is not a requirement for the LTOP Technical Specifications.

Therefore, the LTOP surveillance requirements are not affected.The open permissive interlock surveillance requirements remain unchanged.

E5-7 Five S ecific Plant Im rovements Re uired B The SER on WCAP-ll 36-A The NRC Staff Evaluation Report, Reference 2, documented five key plant improvements in Section 3.0,"Staff Position", which demonstrate a net safety benefit to the plant.These items are addressed below in the same format: NRC Staff Position Item 1: (1)"An alarm will be added to each RHR suction valve which will actuate if the valve is open and the pressure is greater than the open permissive setpoint and less than the RHR system design pressure minus the RHR pump head pressure[justified by WCAP-11736]." CP&L Response for Item (1): The proposed alarm will be added such that when the valve is open and RCS pressure is high, an alarm will annunciate.

Operators will be instructed by procedures to take corrective action to close the suction isolation valves and/or not to pressurize further.The plant specific setpoint for the alarm will meet the criteria set forth in the WCAP.For SHNPP, the open permissive interlock is set at 363 psig and the RHR design pressure is 600 psig.Since the RHR pump total dynamic head is approximately 125 psi, the alarm setpoint (A)will be set at 363<A<600-125 psig.Therefore, operator corrective action, upon alarm annunciation, will prevent catastrophic RHR system piping failure.As noted previously, the alarm will be delayed (0-15 seconds)from setpoint actuation to avoid annunciation for expected RCS pressure perturbations but will annunciate on a sustained signal.NRC Staff Position Item 2: (2)"Valve position indication to the alarm must be provided from the stem-mounted limit switches (SMLSs)and power to the SMLSs must not be affected by power lockout of the valve[justified by WCAP-11736)." CP&L Response for Item (2): Whereas Section 6.4 of WCAP-11736-A discusses the proposed use of seem-mounted limit switches for the new alarm, CP&L proposes to use the existing Limitorque limit switches on the actuator cam/rotor for position indication and the new alarm.The limit switches for position indication are on a separate cam and therefore are not affected by other cam/switch combinations within E5-8 the motor-operator, such as those for torque bypass.These Limitorque limit switches will be powered by the same electrical train as the motor actuators for the valve, except that the power will be taken from the electrical supply ahead of the valve circuit breakers.Thus"racking out" the valve circuit breakers will not affect valve position indication.

The logic and wiring configuration are shown in the attachment mark-ups of Figures 6-16, 6-17, and 6-18 (typical of 4 valves).Alarm annunciation will also be fed from the same indication circuit and will not be affected by valve circuit breaker position.NRC Staff Position Item 3: (3)"The procedural improvements described in WCAP-11736 should be implemented.

Procedures themselves are plant specific." CP&L Response for Item 3: Carolina Power&Light Company will review the SHNPP plant operating procedures to determine the effect of removing the autoclosure interlock and installation of a control room alarm and will implement revisions where necessary.

The review and revisions will encompass those types of procedures identified by WOG and listed in the SER.The alarm response procedure will be revised to reflect the new alarm and corrective action to be taken upon annunciation.

The procedure reviews and revisions will be accomplished as part of the normal modification control process.NRC Staff Position Item 4: (4)"Where feasible, power should be removed from the RHR suction valves prior to their being leak-checked

[plant specific]." CP&L Response for Item 4: For the Shearon Harris plant, CP&L does not believe that removing power from the RHR suction isolation valves prior to their being leak tested is beneficial to plant safety or plant operation for the following reasons: (i)The subject valves are currently leak tested in accordance with plant Technical Specification 4.4.6.2.2.

At SHNPP, plant Procedure OST-1507 requires that this testing be done during the plant heat-up phase in Mode 5, (140-200'F)at RCS pressures between 150 psig and 363 psig.Technical Specifications 3.4.1.4'and 3.4.1.4.2 allow one RHR loop to be inoperable for up to two hours during Mode 5 for purposes of surveillance testing, such as valve leak testing.This may occur if the opposite RHR loop is operable and connected to the RCS loop.Therefore, if any 1 Reference is made to show independence from problems experienced with torque bypass switch/cam settings.E5-9

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unlikely pressure transients were to occur in Mode 5, the operable and connected loop would also be subject to such transients.

Hence, removing power to the RHR suction isolation valve being leak tested would not make any difference to pressure transients impacting RHR piping inside or outside of Containment.(ii)During plant Mode 5 operation, potential pressure transients would be mitigated by the operable RHR loop suction relief valves and the low-temperature overpressure protection system (LTOPS).Therefore, fast pressure transients that are large in magnitude that may challenge RHR piping integrity are not expected to occur.The LTOP setpoints and the RHR suction relief valve setpoints are (450 psig during Mode 5 operation which are well below the RHR piping design pressure of 600 psig.(iii)In addition to the burden of increased procedural complexity, the extra time involved in racking in and out the power supply for each of the two suction isolation valves in each of the two RHR loops could challenge the RHR restriction on the RHR operable loop for Technical Specifications 3.4.1.4.1 and 3.4.1.4.2.

In any case, the additional time for testing (four procedural steps with verification and sign-offs per RHR loop)will increase the unavailability of that loop.This is clearly undesirable because: (a)It potentially reduces the availability of decay heat removal loops;(b)It decreases the availability of the RHR suction relief valves to mitigate any transient pressure event.(Example: backup relief for an LTOP event.);(c)Additional active control steps potentially introduce additional failure points.(iv)If during leak testing, significant valve degradation resulted, operator remote control of the valves could mitigate the consequences of such an effect more quickly than if manual operation or electrical power restoration were required.(v)In the unlikely event of a pressure transient occurring while the isolation valve is closed for leak testing, the valve is prevented from reopening by the open permissive interlock set at 363 psig;therefore, removing power for this mode of operation is an unnecessary restraint.

In summary for Item 4, CP&L does not propose to remove power to these valves during leak testing.E5-10 NRC Staff Position Item 5: (5)"The RHR suction valve operators should be sized so that the valves cannot be opened against full system pressure[plant specific]" CP&L Response for Item 5: The existing RHR suction isolation valves at SHNPP have the capability of functioning against high differential pressures.

However, the valve actuators will be adjusted to meet the inte'nt of the above NRC position statement.

Specifically, the opening torque switch setting will be reset to allow valve opening under design basis conditions, yet be low enough so that the actuator will not allow the valve to open when high differential pressure exists, such as would occur at normal plant full system RCS pressure.Since the closing torque switch will not be adjusted or affected, the valve will still retain the capability to close against high differential pressures should such a situation occur.This method is more beneficial to the plant than to downsize the rating of the valve actuator.In addition to the above proposed changes, the normal open torque bypass switch, nominally set for 5%open travel, will be defeated to enable the open torque switch to be effective over the full open travel movement of the valve.Should the valve fail to lift off its seat upon manual command during normal plant shutdown maneuvers, the Control Room operators could manually bypass the open torque switch from the control board, if desired.If the RHR ACI is deleted as proposed, there will be no automatic actuation of these valves.However, since these valves may perform an important role during shutdown from a postulated accident or abnormal situation, the open torque switch is bypassed as are the thermal overloads for these valves, during a sequencer actuation, consistent with the SHNPP commitment to Regulatory Guide 1.106,"Thermal Overload Protection for Electric Motors on Motor-Operated Valves", as documented in the Final Safety Analysis Report.Since a sequencer signal is expected to be an infrequent condition (safety injection signal or loss of offsite power), the amount of time in the plant life that the open torque switch is automatically bypassed is extremely small.Therefore, in order for the valve to open under high differential pressure at normal plant power operation, this would require multiple scenarios:

failure of plant operators to remove electrical power during startup, failure of two diverse open permissive interlock systems, failure of operator to recognize RCS high pressure condition, operator inadvertently/erroneously attempting to open the RHR suction isolation valves, and the existence of a safety injection or loss of offsite power signal.Since the coincidental existence E5-11 of all of the above scenarios would be required to open the valves, this is judged as an extremely low probability.

It should be noted that valve actuator sizing was not taken credit for in the PRA discussed in the WOG Report.Rather, it was mentioned (erroneously for SHNPP)as a note of conservatism (Sections 3.1, 7.3, 7.5.1, and 9.0).Therefore, neither the results nor the conclusions of the report are affected by the proposed changes noted above.The actuator torque switch adjustments will be made using procedures and criteria developed for CP&L's program in response to NRC Generic Letter GL 89-10,"Safety-Related Motor Operated Valve Testing and Surveillance".

References (1)WCAP 11736-A, October 1989,"Residual Heat Removal Autoclosure Interlock Removal Report for the Westinghouse Owners Group" (2)Letter, Mr.Ashok Thadani (NRR)to Mr.Roger A.Newton (WOG)on August 8, 1989, transmitting the staff's Safety Evaluation Report'Acceptance for Referencing WCAP 11736 Rev.0.0,"Residual Heat Removal System Autoclosure Interlock (ACI)Removal Report" in Plant Specific Submittals'.

E5-12 Q MESTINGHOUSE PROPRIETARY CLASS These valves are twelve-inch, motor-operated, gate valves which are normally-closed except when the RHRS is in operation.

Both valves are provided with a manual control (open/closed) on the Hain Control Board and will fail in the"as-is" position.Valves 1RH-1 (8702A)and 1RH-39 (8702B)are interlocked with RCS pressure transmitter PT-403 and valves 1RH-2 (8701A)and 1RH-40 (8701B)are interlocked with pressure transmitter PT-402.These interlocks prevent the inadvertent opening of the valves when the RCS pressure is above 363 psig.The valves also close automatically when the RCS pressure is higher than 700 psig.A more detailed description of the interlocks is provided in Sectio 5,'/3.Heat Exchanger Flow Control Valves 1RH-30 and 1RH-66 (HCV-603A and HCV-6038)The reactor coolant flow rate through the RHR heat exchangers is adjusted by ten-inch, air-operated, butterfly valves 1RH-30 (HCV-603A) and 1RH-66 (HCV-603B).

Positioning of these valves from the control room regulates the reactor coolant flow and temperature exiting the heat exchangers.

These valves are normally full open during power operation.

Bypass Flow Control Valves 1RH-20 and 1RH-58 (FCV-605A and FCV-605B)These valves, located in the heat exchange.bypass lines, are eight-inch, air-operated, butterfly valves, The valve may be positioned automatically from its associated flow transmitter (FT-605A or FT-605B)or manually from the control room.As the operator positions 1RH-30 (FCV-603A) to regulate the plant cooldown rate, bypass valve 1RH-20 (FCV-605A) automatically repositions itself to maintain a constant return flow to the RCS.1RH-66 (HCV-603B) and 1RH-58 (FCV-605B) act in a similar manner.00320:1D/101089 5-60 J'WESTINGHOUSE PROPRIETARY S 3 closed.When contact K-735 closes, the valve automatically begins to close.Contact K-735, which is in parallel with the Control Board closing switch contact, energizes the valve control circuit in the same manner as described above in the"Closing the Valve from the Main'Control Room." The valve will continue to close until the valve is to<qued closed as described in the referenced section above.When the valve is fully closed, limit switch contact 20/8 will open preventing the re-actuation of the closing contactor from contact K-735 due to the reset of the torque switch contact (20/17).After the valve is fully closed, it cannot be opened because the opening circuit is locked out as described above in the"Opening the Valve from the Main Control Room" section.Reactor Coolant S stem Pressure Control Loo The Reactor Coolant System hot leg pressure channel, PT-402 is used to provide the interlock signals for the RHR inlet isolation valves 1-8701A and 1-87018.PT-403 is used to provide the interlock signals for RHR inlet isolation valves 1-8702A and 1-87028.Each pressure control loop consists of the pressure transmitter (PT-402 or PT-403), a channel test card, a loop power supply/current to voltage transformer, a signal isolator, a dual circuit signal comparator, and two aux relays.The pressure transmitter measures the RCS pressure and provides a current output signal that is proportional to the measured pressure.The loop power supply takes the 4 to 20 mA current signal from the pressure transmitter and converts it to a 0 to 10 V proportional voltage signal.The non-isolated output of the loop power supply is input into the signal isolator and into the dual comparator.

The dual comparator compares the pressure signal (input voltage)to the given setpoints.

The comparator outputs are 0 VDC or 24 VDC depending on the signal to setpoint comparison.

The 0/24 VDC outputs control'he aux relays which control the 118 VAC K-734 and K-735 relays.The K-734 and K-735 relays open and close the valve contactor K-734 and K-735 contacts.The A comparator 4k'AAf/WIZEN output is when the pressure is below 363 psig, which nergizes the aux relay, which energizes the,K-734 relay, closing the K-734 contacts.s(e de 00320:10/101089 5-70

~'t WESTINGHOUSE PROPRIETARY CL 3)he g comparator output is 24 YOC when the pressure is above 700 psig,~h energizes the aux relay, which energizes the K-735 relay, closing YYhi c the K-735 contacts.The various test points and jacks are used during gain ntenance and calibration of the instrument loop.discussed above, the dual circuit signal comparator is used to provide Pis~;stable output signals (either on or off)depending on whether the easured signal is above or below the setpoint.g g>ecifically, for the RHR valve interlock circuit, whenever the RCS pre yessure measured by the pressure loop exceeds the valve closing setpoint (700 psig), the dual comparator output circuit (B)will energize the aux relay, which energizes the K-735 relay closing the associated contact y,-735 in the valve closing contactor circuit, causing the valve to close qq discussed above.whenever the RCS pressure is below the valve closing setpoint, the comparator output circuit will de-energize the aux relay, which de-energizes the K-735 relay, opening the associated contact K-735 in the valve closing contactor circuit, allowing the valve to remain open.Similarly, for the valve opening comparator output, whenever the RCS pressure exceeds the valve opening setpoint (363 psig), the dual comparator output circuit (A)will-nergize the aux relay, which nergizes the K-734 relay, opening contact K-734 in the valve opening contactor circuit and preventing the valve from being opened as discussed above.Whenever the RCS pressure is bel w the valve opening setpoint, the comparator output circuit (A)wil>en rgize the aux relay, which M ergizes the K-734 relay, closing con act K-734 in the valve opening circuit, permitting the valve to be opened from the Hain Control Board control switch.0032 D:1D/101089 5-71 STIHGHOUSE PROPRIETARY CLASS 3 CINTAItOKHT SINP IRH-69 FX.AC ICI IRII-58 ISI-329 Ct IARGDIG/SI PUHP SUCTIQH ZRit-7BP IRH-45 ISI 323 PUHP-IB-SB I-9420B RHR HX IB-SB I-94608~IRII-70 ISI-341 ISI-330 ISI-327 H RCS Cn D ISI-358.ISI-83 LQQP 3 LEG G ISI-353 ISI 321 Rvsr IW431B x CCV IS 1359 RCS HQILEG RCS CO D LEG IS1-357 ISI-82 UXP 2 RCS HH'EG LQQP I IRH-7 IRH-I IRH-2 ISI 322 z ISI 320 vv:[mc PUHP-IA-SA IRtl-19 FW HC.ICI IRH-20 RHR HX IA-SA I-9431A x f 0 hr.o.)i IRH-30 ISI-326 CHAR GIHG/Sl PUHP SUCTIQtl ISI328 ISI-340 ISI-346 G IS1-352 ISI-356 ISI-81 RCS CO D LEG LQOP I SI A.PER YURE CARD LEGEND RVST IRI(&4 LC.IRH-26 L C.i't~--.-'vai)able On~q=.'.are Card Figure 5-18 LIL-LOCKED tREN FZ.-FAILS CLQSED FB.-F'AILS QPEH IIII.-tCRHALLY~t HC.-MRHALLY CLQSED 2/11/88 HQTQR CPERATED VALVE~emW VALVE IICII~~>~mm trauma vALvc~aaaC VALVE FZ.ICS-28 CVCS LET DQQI SHEARON HARRIS RESIDUAL HEAT REMOVAL SYSTEM SHEARON HARRIS CPL-2165-S-1324 REV 3 CPL-2165-S-1310 REV 4 CPL-2165-S-1308 REV 3 I CPL-2165-S-1304 REV 3 GROUP 4 LEAD PLANT Shearon Harris Residual Heat Removal System 5-89 got I W nou~-~I

'I~>>4 (I t VEST GUSE PRGPRIETARY CLASS~~4 OIAI46L.-UXS'QVER SIMPLY ISIJLTT74 hUX RELAY HASt P h0X RELhY lleVAC lleVAC CPEH PERMSSIVE 4K734>TRA84 h 38 34 86 28 g 4 bo+ao bo 6CHZ+ae be+ae be 74-8 74-1 49 37 45 47 41 43 87 85 65 67 SI41VH TTR VALVE SICJT 74-4 V 74 Z (STEX IPOI}48 4Z S CR/lh 1789 48 S 48 0 (sax wn)0 mO-lbOea 9 X S]f A.PERT URF SPRIHG RETIIRH 10 16784K 42 S MITE L K734 CLOSES hl'CS PRESSC PHD K735 ELAPSES AT RCS PRESS>rfO PSIG bailable On-e Card 20/LIHlT SV DEVELOPHEHT MOTOR CR/lh 1789 EBASCO STH VALVE QPHG 100 CVD SH LEGEND 16 15 2/11/88 l)hlR CNCuTT TRh44SmeER FIGURE 5-20 SHEARON HARRIS RHRS SUCTION/ISOLATION VAL'VE CONTROL CIRCUITRY-HOV-8701B (1RH-40)14 17 IPOES 04 OVLS I74 CUISE STRK cpQcs 114 Ix.vs I74 IFOI STRK 18 REPS chR CI66 8-441 sH 386 V aa4578 SH II gyIT CUTSE8~e TIGS SIEET 5-92

~4 0 b~1 VESTI USE PRCIPRIETARY CLASS 3 0~PRESSLJK TRAtlQCTTOL h0S RE1AY lloVAC (PEN PO00SSIVE CK734>TRAIH h lhl 33 A~AUX RELAY 118VAC 0(735)NASl TRATH h PY/402A2)))74-1 49 HT 25'7 K734 37 45 47 41 43 65 67~pO 74-1 V CR/1 A 1789 74 2 42 S 0 0{aa rm)2b-I YC (sxn wn)0 42 S 42 S oeL A ACARH SI Ap j4 g'f Ugg CARD~Iso Available Og Aperture Card-4/0&PROPOSEo oEcE7Ioh/CP fl sPrclfic PILoPosza cHANGE5 HGTOR 49 at CR/lh l789 TC~DECFTk~EBASCG CONT VALVE GPNG 100 CVD H ac PROPOSED CHpwgp 20/LIHIT SV De.VELGPHENT LEGEND I means~[)Figure 6-18.Shearon Harris Fleeentary Wlrlng Dlagra~changes For HG',v'8701A ppp saO NC aC 10 12 14 13 16 I/19/88 17 18 tPEHS 134 OVLD CH CLCSC STRK--CTSa mSC0~-TMS aX COJVl AC7 DEgfgOP~A/7 S//DQA'/480VE

/~~~chR 2166 9-401 sH 325 aco~a7/u oa V V 2034578 SH 11 6-25

)e~e MESTINGHOUSE PROPRIETARY CLASPS Valve interlock with 1 8701 A (Train A 1-8701 8 (Train A 1<702'(Train 8-8702 8 Train 8)402 PT (Train RCS Hot Leg A)'ressure 402 (Train A)403 (Train B)403 Train 8)RHR to CVC5 Rec.Valve RNR RMST uction Valve 1-8706 A (Train A 1 8809A M.01 (Train A-8706-8706 8 A SQ.e2 SQ.i2 (Train A)(Train 8)1-88098 1-8809A SM.i2 SM.42 (Train A (Train B)1-8706 8%.>l (Train 8)1-88098 5'M.41 (Train 8)SM~Switch l'mi ToEE ua j'~E'7" MOTE: SM il-s~itch powered by sane train as valve.SM t2-SteYII aounted limit switch powered by train different frNII valve power.figure 5-19.Shearon Harris Current Interlock Logic-MOVs-8701AIIB, 8702A&B (1RHI, 1RH2, 1RH-39, 1RH-40)Sheet 2 of 2 10320:10/101089 5-91 ESTINGHOUSE PROPRIETARY CLASS Valve Interlock with PT RCS Mot Leg Pressure 1-8701 A (Train A 402 (Train A)i-8702 (Train A 402 (Train A)1-8702 A (Train B 403 (Train 8)-8702 B Train B)4u3 Train 8)RMR to CVCS Rec.Valve RMR RMST Suction Valve 1-8706 A W.<<T (Train A 1-8809A SW.<<1{Train A-8706 1-8706 8 A (Train A)(Train B)1-88098 1-8809A SM.<<2 SW.<<2 (Train A){Train 8)1-8706 B~W.<<1 (Train B)1-88098 SW.$1 (Train B)SM~Switch L'mi'tO//p e lani'" NOTE: SW<<1-5 gee-witch powered by same train as valve.SM<<2-Stem mounted limit switch powered by train different from valve power.Figure 6"16.Shearon Harris Proposed Interlock-hlOV 8701A&B, 8702A&B{Sheet 2 of 2)lo:10/021188 6;23 STINGHOUSE PROPRIETARY CLASS 3 MOV-8701AKB (MOV-8702AhB)

DEICE 6w EVF RN.P0~W ALARM/MONITOR LIGHT INOI CATION SEPARATE FRO Jg vec.vgcourROL POkltR Figure 6-17.Shearon Harris Proposed Position Indication MOV's-8701A,B 5 8702A,B 0:10/021188