PY-CEI-NRR-2230, Application for Amend to License NPF-58,incorporating Temp Control Valves & Associated Bypass Lines Around Emergency Closed Cooling Sys Heat Exchangers

Application for Amend to License NPF-58,incorporating Temp Control Valves & Associated Bypass Lines Around Emergency Closed Cooling Sys Heat Exchangers

ML20217K639
Person / Time
Site:	Perry
Issue date:	10/22/1997
From:	Myers L CENTERIOR ENERGY
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20217K643	List: ML20217K650 PY-CEI-NRR-2230, Application for Amend to License NPF-58,incorporating Temp Control Valves & Associated Bypass Lines Around Emergency Closed Cooling Sys Heat Exchangers
References
PY-CEI-NRR-2230, NUDOCS 9710280355
Download: ML20217K639 (13)

Text

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% dwim Pdwer Generation Group l

Perry Nucioar hwer Piard Matt A&kess: 216-216 6916 Lew W.Myers 10 conier Road P O Ba 97 FAX:21tLPl@e0P9 Veo hesdort i Perry.oNo 44041 Posty. CH 44081 4

October 22,1997 PY-CEl/NRR 2230L United States Nuclear Regulatory Commission .

Document Control Desk Washington, D.C. 20555

Perry Nuclear Power Plant Docket No. 50-440 10 CFR 50.59 and 10 CFR 50.90 Request Regarding Temperature Control Valves Ladies and Gentlemen:

Pusuant to 10 CFR 50.59 and 10 CFR 50.90, Nuclear Regulatory Commission (NRC) review and approvalis requested on a change to the Perry Nuclear Power Plant (PNPP) Unit 1 as described >

In the Updated Safety Analysis Report (USAR). The change will incorporate temperature control valves and associated bypass lines around the Emergency Closed Cooling (ECC) System heat exchangers. Thase features are designed to ensure operability of the Control Complex Chilled Water System under post accident load conditions, without need for compensatory measures.

Attachment 1 provides - Summary, Description of the Proposed USAR Changes, a Safety Analysis, and an Environmental Considesration. Attachment 2 provides the Significant Hazards Consideration. Attachment 3 provides a copy of the annotated USAR pages.

There are no regulatory commitments in this letter or its attachments. Any actions discussed

, In this document represent intended or planned actions and are described for the NRC's information, if you have questions or require additionalinformation, please contact Mr. Henry L. Hegrat, Manager Regulatory Affairs, at (440) 280-5600.

Very truly yours, /

/ -

Ql for Lew W. Myers Attachments ,, ,, ,

cc: NRC Project Manage'r NRC Resident inspector NRC Region til State of Ohio 9710290355 PDR 971022 ADOCK 05000440, ll l l ll p PDR

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Attachm:nt 1 PY CEl/NRR 2230!

Pega 1 of 10 l

l BUMMARY In accordance with 10 CFR 50.59 and 50.90, Nuclear Regulatory Commission (NRC) review and approval is requested on changes to the Perry Nuclear Power Plant (PNPP) as described in the Updated Safety Analysis Report (USAR). The USAR changes incorporate descriptions (in the form of text, tables and drawings) of a modification to the plant involving two temperature control valves and associated temperature elements, and piping segments that have been installed in the Emergency Closed Cooling (ECC) System. These valves, temperature elements, and piping segments were installed to increase the overall reliability of the ECC System and the other safety related plant systems that it serves, to help ensure that they perform their specified safety functions without reliance on manual throttling actions. Details including overall system descriptions and specifics about the history of ECC Lesign at PNPP are provided after a description of the proposed USAR changes. Also included are specifics on the overall design of the temperature control valve modification. Additional details are avallat,'e on site in the design modification package.

/

This change is being submitted for NRC review and approval as a result of a recently revised 10 CFR 50.59 evaluation, which determin3d that the addition of the temperature control valves into the ECCW system had resulted in a very smallIncrease in the "probaollity of occurrence ...

of a ... malfunction of equipment important to safety previously evaluated in the safety analysis report." Although this modification is considered to provide a significant safety benefit and improve the reliability of the ECC system,10 CFR 50.59 requires submittalin accordance with 10 CFR 50.90 due to the above determination.

Following NRC approval, the attached USAR changes will be incorporated into the USAR in accordance with 10 CFR 50.71(e).

DESCRIPTION OF TliEERQEOSEDESAR CHANGES The installation Sithe temperature control valves and the bypass line around the ECC Heat Exchanger will result in updates to the USAR text and tables / figures as marked in Attachment 3. A summary of these changes follows:

TEXT e Section 7.3.1.1.6.c *ECC System Opration" (pg. 7.3 35) is updated to reflect use of the temperature control valves, rather than the previous manual methods of throttling flow in the winter, as the means of maintaining the ECC temperature above the Control Complex Chillers' low inlet temperature limit.

• Section 9.2.2.5 ' Instrumentation Requirements" [for the ECC system) (pg. 9.2 32) currently states that the position of power operated valves in ECC are indicated in the Control Room. This section is updated to note that the temperature coritrol valves are an exception to this generic statement.

Section 9A, " Fire Protection Evaluation Report' (pgs. G 14 through G1-7) is updated to reflect the addition of the new ECC ' Safe Shutdown system' components and circuitry to applicable fire zones, o

Attachment 1 -

4 / ,

PY CEl/NRR 2230L Page 2 of 10 4

. TABLES / FIGURES e Table 3.9 30 ' Summary of Active Valves (Non NSSS)* (pgs. 3.9 355 and 3.9 359) is updated to add the temperature control valves.

• Figure 7.3 8

• Hydrogen Analysis System"is updated to reflect ECC parameters as a  !

, result of revised heat balance analysis.

• Table 8.31 " Connected, Automatic and Manual Loading and Unloading of Safety System Switchgear" (pgs. 8.3104,109,110, and 119) is updated to add the electrical loadings of the temperature control valve hydraulic actuators. t e Figure 9.2-3

• Emergency Closed Cooling System *; Sheet 1 of 5 is updated to show the ' 1

piping modifications, and Sheet 3 of 5 is updated to detail the design flow parameters. <

e Figure 9A-6 ' Fire Protection Evaluation Units 1 and 2 Control Complex Plan - El. 574' I 10" le updated to show the new valves in their applicable fire zones.

RAFETY. ANALYSIS BACKGROUND l GeneraLSystem Descriotions 3

The ECC System (P42)is composed of two separate, redundant closed loops designed to

provide a source of safety related post accident cooling water to the Emergency Core Cooling

!' Systems and their supporting components, the Control Complex Chillers, the Reactor Core Isolation Cooling (RCIC) room cooler, and the post accident Containment Hydrogen Analyzers.

3 The ECC System as described in the USAR is designed to account for single failure criteria.

- Specifically, the following components are supported by the ECC System:

Loon "A" (ESF Div.11 Loop "B" (ESF Div. 2)

Control Complex Chiller "A" Control Complex Chiller "B" Hydrogen Analyzer "A" Hydrogen Analyzer"B" LPCS Room Cooler RHR "B" Room Cooler RHR Pump "A" Seals RHR Pump "C" Seals RHR "A" Room Cooler RHR "C" Room Cooler RCIC Room Cooler RHR Pump "B'_' Seals in order for the ECC System to provide cooling water to its supported systems, the system has been designed with heat exchangers which interface with the Emergency Service Water (ESW)

System (P45). The heat generated from the ECC supported systems is transferred to the ESW System which utilizes Lake Erie water as the fluid medium and its ultimate heat sink. The ESW a System typically provides cooling water to equipment required for normal and emergency shutdown of the reactor.

The primary reason for this modification is to ensure the availability of the Control Complex Chillers (P47). The P47 System is designed to cool the Control Room and other areas in the

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Attachm:nt 1

• PY CEl/NRR 2230L

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Control Complex by supplying chilled water to the cooling coils of heating, ventilating, and air conditioning (HVAC) systems.  !

1 The modification also stabilizes the supply temperature and flows to the ECC serviced components.  !

During normal operation, the Control Complex Chillers are provided with cooling water from the r non safety related Nuclear Closed Cooling (NCC) System (P43). During accident conditions, the cooling water supply to the Control Complex Chillers is automatically transferred from NCC to the safety related ECC System.

History of ECC Cooling.at PNPP The original ECC System derJgn, as described in the Final System Design Description for the Emergency Closed Cooling System, and us installed in the plant, included a temperature ,

controlled, motor operated, modulating valve on the ECC System outlet of each Control Complex Chiller (See Figure 1). The purpose of this valve was to throttle cooling water flow theough the Control Complex Chillen) so that the ECC System water leaving the chillers did not .

fall below the temperature required by the Control Complex Chiller design.

Before(ORIGINAL DCP DESIGN)

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LPCS ROOM COOLER Figure 1

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Attachment 1 PY CEl/NRR 2230L Pagg 4 of 10 Based on design and operational concerne, the motor operated throttling valves were disabled and Design Change Package (DCP) 86 224 was implemented te install a bypss line on the ESW System for use during conditions when the ESW temperature wnn halow 55 degrees F.

Reliance was placed upon the establishment of wir, tar ant' vmer modes of operation, with ESW flow directed through the smaller bypass line in the winter. DCP 92 0060 was later implemented to permanently incorporate the removal of control power from the disabled ECC motor operated throttling valves, in 1994, 'ollowing implementation of DCP 92 060, Licensee Event Report (LER) 94 005 was written to document the potential for rendering the Control Complex Chillers inoperable due to low Inlet water (ECC) temperature. This was postulated to occur during winter operation with the lake temperature less than 55 degrees F with minimal heat loads. Under this condition, the ESW system would overcool the ECC water below the minimum inlet design temperature of 55 degrees F for the Control Complex Chillers. One of the corrective actions from LER 94-005, ,

Revision 1, implemented throttling of a manual valve in the " winter mode" bypass line, to maintain ECC temperature within the appropriate temperature band (55 degrees to 95 degrees F) following various events.

DGP 94-0027 was implemented to address the overcooling design deficiency and provided all season temperature modulation through the installation of a bypass line around each of the ECC heat schangers and control of the flow through the ECC heat exchangers using three-l way Temiwroture Control Valves (TCVs) 1P42 F665A/B.

Subsequently, the NRC issued a Notice of Violation in Inspection Report 50-440/97002, noting that "...your record of a safety evaluation required by 10 CFR 50.59, regarding a modification of the emergency closed cooling system, did not adequately support your conclusion that the probability of a malfunction was not increased or that the potential for a different malfunction was not introduced." Actions were taken to disable the temperature control valves during a June 1997 outage at PNPP, to ensure that an unreviewed safety question did not exist. These actions were discussed in a letter dated June 13,1997 (PY CEI/NRR 2180L). The submittal of this item as an unreviewed safety question / license amendment request under the provisions of 10 CFR 50.59 and 50.90 has resulted from the long term corrective actions outlined in the June 13,1997 letter.

Summarv Description of the Temperature Control Valve ModificatioD_P_ackage DCP 94-0027 installed a separate bypass line around each of the Emergency Closed Cooling (ECC) System (P42) heat exchangers. Each bypass line utilizes a three-way electro hydraulic modulating Temperature Control Valve (TCV) to distribute the flow between the heat exchanger and the bypass line based on the ECC water temperature downstream of the heat exchanger (See Figure 1).

DCP 94-0027 also includes instrumentation, electrical interfaces, piping support changes, structural interactions, and piping modifications necessary to install the TCVs and the associated ECC heat exchanger bypass lines. Previously spared instrumentation and cables were utilized. Removal, repair and replacement of tray fire barrl:.r material for addition of new cables and rework of the existing cables was also required.

Attachment 1

, , PY CEl/NRR 2230L

, Pago S of 10 i 4

DCP 94 0027 was designed to maintain the ECC temperature at the inlet to the Control Complex Chillers above 55 degrees F during normal and accident conditions during all seasons; the most limiting configuration was during winter operation with minimum heat loads.

i The design accommodates the following modes of plant operation as described on drawing D- ,

302 623 and USAR Figure 9.2 3 to prevent the trip of the Control Complex Chillers:  :

e Hot Standby with Loss of Preferred AC Power i

e Normal Shutdown 4

e Continuation of Normal Shutdown after 20 Hours J

e Post Accident with Loss of Preferred AC Power j

Operation of ECC outside these modes with little or no heat load is accomplished through plant f i procedural / administrative controls, i ANALYSIS OF THE ITEM To ihE EVALUATED

System Design and LicensingEasts The ECC System is a safety related system designed to ASME Section lil, Safety Class 3, and

to Seismic Category I criteria. The system has been designed to support the Emergency Core

Cooling System equipment.

s ""s ECC System, as described in Safety Evaluation Report (SER) 9.2.2, satisfies General Design Criteria 2,4,5,44,45, arid 46, in addition to Regulatory Guide 1.29, Positions C,1 and C.2. These Design Criteria involve topics related to the system's protection against natural phenomena, shared functions, capability for transferring the required heat loads, and inservice t inspection and functional testing requirements. Regulatory Guide 1.29, Positions C.1 and C.2 involve seismic classification requirements. .

j System descriptions of the ECC System and the ESW System are described in USAR Sections

9.2.2

• Emergency Closed Cooling System" and 9.2.1

• Emergency Service Water System."

Modfic.ation Arialysis l

An analysis of the modification was performed to ensure compliance to the original design basis  !

4 of the ECC System. As part of the analysis, the following aspects were evaluated.  !

Mechanical System Analysis In accordance with the original ECC System design, the valves and associated piping for this  :

modification (pipe, fittings and supports), were designed, specified, and procured to meet the 3

requirements of ASME Section Ill, Safety Class 3, Seismic Category 1. The modification was

. Installed in accordance with the existing ECC System Pipe Specification SP 2000, Line Class L1 3.

Calculations were prepared to demonstrate that the valve size is adequate to ensure that performance of the ECC System is maintained for all modes of operation for which it was

, designed. The bypass line size was selected and validated in the calculation. Additionally, it was analytically demonstrated that cavitation would not occur at the ECC pumps or new TCVs, l

Attachment 1

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PY CEl/NRR 2230L l r

Pcge 6 of 10 l I

Also, changes to the plant operating data (pressure, flow, and temperature) as shown on the revised P&lD D 302 623, and USAR Figure 9.2 3 (sheet 3 of 5) are within design allowabler..

ElectricalSystem Analysis Evaluation of existing calculations demonstrated that the system short circuit and system l voltage analyses are not adversely impacted; that the safety related buses can accept the additional electrical loads imposed by the new TCVs; and that the respective Emergency Diesel Generator loading is acceptable when considering this additional load as reflected in USAR Table 8.31, Evaluation of existing calculations also demonstrates that the new power circuits are properly protected and selective coordination is achieved between the new protective i device and the upstream protective device, i

Fire Protection / Appendix R Safe Shutdown Analysis i The TCVs and the associated components added by DCP 94 0027 have been evaluated against the PNPP Safe Shutdown Capability Report for Appendix R/ Fire Protection purposes as  ;

contained in USAR Section 9A.

As a result of the design review, it was identified that a fault initiated by a Control Room fire could cause the valve to fall, in this event, manual actions will be used to restore actuator control power as well as position the valve. The use of manual actions are acceptable on the >

basis that Appendix R has previously evaluated and credited the use of manual actions for the use of the ECC System for a fire. There is no immediate need for ECC cooling on the basis that a LOOP /LOCA condit;on is not postulated concurrently with a fire event. Therefore, circuit isolation to protect the Method A valve from the effects of a fire in the control room is not  !

needed, and control at the remote shutdown panel is also not needed.

The~ additional combustibles as a result of this DCP were evaluated. This evaluation concluded that the additional combustibles did not significantly affect the combustible loading of the area.

The safe shutdown equipment and circuits for the redundant trains on the Control Complex 574' elevation are separated from the new conduits or have been previously evaluated as having an adequate level of protection. In other fire areas, the circuits associated with this change are routed in existing raceways, which have been previously evaluated for separation between redundant trains. The raceway fire barriere that are relied upon to provide protection of circuits have been replaced with a new 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> fire rated barrier, Automatic fire suppression and detection are already provided in the area of the new valves and associated instrumentation. The existing equipment and new valves are qualified for a wet environment (NEMA enclosure) and will not be adversely affected by water spray from the t sprinklers.

Probabilistic Safety Assessment An evaluation of the impact of this modification on the PNPP Probabilistic Safety Assessment was performed with respect to core damage due to failure of the TCV The subject evaluation developed and quantified a fault tree on an ECC subsystem which included the bypass line and associated TCV. The results of the quantified fault tree show that the addition of a bypass line

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Att:chment i PY-CEl/NRR 2230L Pag) 7 of 10 around the ECC heat exchangers and the addition of the TCV have a negligibh impact upon the core damage frequency (CDF).

~

Post Modification Testing Functional and pressure testing requirements were specified in accordance with plant procedures. ECC flow was verified to fully bypass the ECC heat exchangers under low or no '

heat load conditions at low lake temperatures. However, following return to service, it was observed that heat loss from the system still occurred at a very low rate while in the heat exchanger bypass alignment. Infrared thermography revealed that flow currents from the bypass piping system adjacent to the heat exchanger discharge nozzle were creating an exchange of cold water from the heat exchanger with the warmer water of the ECC s> stem, resulting in gradual cooldown.

Because of this phenomenon, the design provided by DCP 94-0027 may not maintain ECC

system temperature aoove 55 degrees F under low or no heat load conditions at low lake water temperatures. To compensate for this situation, operation of the ECC System during normal plant conditions with little or no heat load (e.g. surveillance testing) with ESW supply ternperature below 55 degrees F is accomplished through administrative and procedural controls, if an accident were to occur during this evolution, the minimum ESW flow needed for removing accident heat loads will still be maintained.

During accident plant conditions, sufficient heat load will be available on the ECC system to compensate for the above phenomenon such that no administrative controls are required.

Other Miscellaneous Impacts As part of plant procedural design program requirements, other interface reviews of this design change were performed to consider the following design aspects:

ALARA

- Equipment Qualification Missile Protection

- Heavy Loads

- HVAC / Control Room Habitability Piping & Equipment Analysis / Pipe Supports Seismic / Structural Instrumentation & Controls The results of these reviews indicate that the proposed design change has no effect on the analysis, qualifications, procedures, and instructions evaluated or implied previously in the USAR.

Failure Analysis The modification was analyzed for credible failures with attention to identifying an increase in probability of occurrence or the creation of a different type of a failure mechanism outside of the original system design and licensing basis as previously evaluated in the USAR.

-. _ ~- ____

Attachm:nt 1 PY CEl/NRR 2230L ,

Page 8 of 10 The term ' equipment ' ,iportant to safety as previously evaluated in the USAR" involves the ECC System as a i ole, the individual loops of ECC, and the individual components, with sr'3cific attentinr a assoc!ated heat exchangers, the electrical supply systems, and the ECC suppodes 4tems including the Control Complex Chillers, the Hydrogen (A/B) Anal', zers, the LPCS Roorn i soler, the RHR (A/B/C) Room Coolers, the RHR (A/'1C) Pump Room Seals, the RCIC Room C, ler, and any other supported important to safety systems not directly mentioned, but associated with the system interface.

Failure Modes and EffectSAnalysjs The following failure analysis describes the potential failure mechanisms and the overall associated effects.

1. Common Mode Failuta The bypass lines and the associated components, logic, and electrical supplies have been designed in accordance with the original ECC System design criteria. The components associated with this modification have been qualified to the same environmental conditions, including seismic application. On the basis of conformance to the original design specifications and criteria, common mode failure has not been introduced.

A fire in the Control Room could induce a fault which could result in the TCV falling as is.

However, as previously discussed in the fire protection / Appendix R Safe Shutdown evaluation, this does not result in a failure to safely shutdown the plant.

2. Pine R@tute The piping and associated piping components have been designed, procured, and installed in accordance with the original design specifications and codes / standards of the ECC System. Failure of these components would result in the loss of inventory from the -

respective loop, thus resulting in complete loss of that loop's function. The effect of a rupture in the new line will result in exactly the same effects as a rupture in any ECC line.

Considering the single failure criteria application, the ECC System would still maintain its design function via the redundant loop. Considering the potential for flooding and its effect upon equipment important to safety, a rupture in the ECC System is bounded by the postulated crack in the Service Water System piping as described in USAR Chapter 3.

3. Temperature ControlValve and Associated Logic The temperature control valves could fail in full flow bypass of the heat exchanger, full flow through the heat exchanger, or an intermediate flow position.

a. Fall As-Is Depending upon the extremes, a potential complete overcooling er complete undercooling of the system could result. The consequences of the fail as is potentials are described below.

Attachment i

' ' PY CEl/NRR 2230L Pcg3 9 of 10

b. Full Flow Bypass of the Heat Exchanger in the worst case analysis, full bypass of the heat exchanger would result in the loop not performing the heat removal capabikty as it was designed. The failure would have a direct effect upon the safety related loads being serviced by the system. This failure mode, however, would be no different than the loss of the ESW System, as described in USAR Section 9.2.1, which provides the cooling mechanism to the heat exchanger,

c. Full Flow Through the Heat Exchanger Full flow could be routed through the heat exchanger, if the lake temperature was below the 55 degrees F design cooling water minimum temperature of the Control Complex Chiller, the operation of this system to support accident mitigation could result in loss of the Coritrol Complex Chiller function. The remaining supported systems would not be impacted by this overcooling effect. The loss of the Control Complex Chiller would not be a failure mode different from that present in the previous design.

Failure Probability Analysis

1. AdditionalBypass Piping On the basis of conformance to the original standards, the modification can not result in a compounding effect or act as an initiator to increase the probability of occurrence of a malfunction of any previously evaluated components.

2. Temperature ControlValve and Associated Logi:

a. FullFlow Through the Heat Exchanger Since these valves are considered active components, and the new three way temperature control valves have been decigned, procured, specified, and installed with the applicable codes and standards of the system as previously discussed, the probability of a failure of the new component is equivalent to the probability of failure of the previously evaluated components or actions, (original modulating valves, and likewise the operator actions which evolved from disabling the original valves),

b. Full Flow Bypass of the Heat Exchanger USAR Section 9.2.1 describes the ESW System design and function. Under this design, a failure of the supporting ESW System loop results in failure of the associated ECC loop. The failure of the ESW System to operate, as previously stated, could be due to any active or passive failure, either mechanical or electrical, including failure of receipt of the LOOP /LOCA signal, and is independent of the design of ECC.

The new component: are not interlocked or intetconnected such that any previously evaluated component failures could be increased or compounded. Thus, the new components do not act as an initiator for failure of any previously evaluated components. Likewise, the probability of common mode failure has not been increased such that USAR 9.2.2.3 has been changed. Hence, the previous probability of losing an

Attachm:nt i

• • ' PY CEl/NRR 2230L Page 10 of 10 ECC loop due to component failures in the ESW System or even those in the ECC System significantly outweigh the probability of ECC loop failure due to the addition of this modification.

The addition of the bypass line and the temperature control valve, however, can be i concluded to result in a slight increase in the probability of occurrence of the loss of the i heat removal capability of the ECC System due to the addition of safety related active  :

components which must function post accident. The loss of heat removal capability would result from the potential failure of the bypass valve resulting in the full flow bypass of the heat exchanger.

Failure Analysis Conclusion Based on the above failure analysis, it can be concluded that, although not significant, a sligh' increase in probability has been Introduced due to a configuration different than -!

previously evaluated in the USAR.

ENYRQNMENIALCONSIDERATION The proposed request was evaluated against the criteria of 10 CFR 51.22 for environmental considerations. The proposed changes do not significantly increase individual or cumulative occupational radiation exposures, do not significantly change the types or significantly increase the amounts of effluents that may be released off site and, as discussed in Attachment 2, do not involve a significant hazards consideration. Based on the foregoir.g, it has been concluded -

that the proposed changes meet the criteria given in 10 CFR 51.22(c)(9) for categorical exclusion from the requirement for an Environmental Impact Statement.

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s Att: chm:nt 2 I PY CEl/NRR 2230L Page 1 of 2 SIGNIFICANT HAZARDS Cr'NSIDERATION The standards used to arrive at a determination that a request for amendment involves no significant hazards considerations are included in the Commission's Regulations, 10 CFR 50.92, which state that the operation of the facility in accordance with the proposed amendment would not: (1) involve a significant increase in the probability or consequences of an accident previously evaluated; or (2) create the possibility of a new or different kind of accident from any previously evaluated; or (3) involve a significant reduction in a margin of safety.

The proposed amendment has been reviewed with respect to these three factors and it has been determined that the proposed change does not involve a significant hazard because:

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

The proposed amendment is requesting Nuclear Regulatory Commission (NRC) review and approval of changes to the Perry Nuclear Power Plant (PNPP) Updated Safety Analysis Report (USAR) to incorporate descriptions (in the form of text, tables and drawings) of a modification to the plant involving two temperature control valves and associated temperature elements, and piping segments that have been installed in the Emergency Closed Cooling Water (ECC) System. These valves, temperature elements, and piping segments were Installed to increase the overall reliability of the ECC System and the other safety related plant systems that it serves, to help ensure that they perform their specified safety functions without reliance on manual throttling actions.

The probability of occurrence and the consequences of an accident previously evaluated in the USAR are not considered to be increased as a result of the temperature control valve modification.

Based on conformance with the original system design criteria, the fact that the ECC System is an accident mitigation system, and that this modification uoes not introduce any new initiators to a previously postulated accident, the addition of this temperature control function can not increase the probability of occurrence of an accident previously t evaluated in the USAR. Accidenis reviewed involve the Loss of Coolant Accident applications described in USAR Chapter 6 with their corresponding consequence postulations shown in USAR Chapter 15, accident and transient scenarios as described in USAR Chapter 15, flooding and rupture postulations as described in USAR Chapter 3, and fire protection analyses as described in USAR Chapter 9.

The modification has been designed, procured, and installed to the original design codes and standards. The modification also satisfies single failure criteria and does not adversely affect the mitigation function of the ECC System. Therefore, the ability to hiitiga&becidents previously evaluated in the USAR is maintained and the radiological consequences of such accidents remain unaffected.

s

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Att'_chment 2 PY CEl/NRR 2230L Page 2 of 2 SIGNIFICANT HAZARDS CONSIDERATION Therefore, the proposed changes do not involve a significant increase in the probability or consequences of previously evaluated accidents.

2. The proposed change would not create the possibility of a new or different kind of accident from any previously evaluated.

The modification has been designed to satisfy the requirements of the original ECC System. A single failure of the new configuration will not result in more than the loss of one respective ECC System loop as already analyzed. Analysis of flooding shows no scenario greater than the currently bounding event. Missile generation is not a concern since no mechanisms conducivt to that potential have been introduced. Froin the electrical analysis perspective, analysis has shown no adverse effects on the Emergency Diesel Generator loadings or other system applications.

Based on the above discussions, the proposed change would not create the possibility of a new or different kind of accident than those previously evaluated.

3. The proposed change will not involve a svgnificant reduction in the margin of safety.

This request does not involve a significant reduction in a mar 0 in of safety. _The modification, including design, procurement, and installation, has been performed in accordance with the applicable codes, standards, and Installation specifications. The modification does not change the heat removal capabilities or any previously designed parameters of the ECC System. Hence, the ECC System margin of safety with respect to safety classification, protection, redundar.cy, heat removal capability, and seismic classification remains unaffected.

The margins of safety contained in the Technical Specifications and the associated Bases also remain unaffected by this modification due to conformance with the applicable codes, standards, and installation specifications. Specifically, Technical Specification 3.7.10

• Emergency Closed Cooling Water (ECCW) System' and the description in the Bases remain unchanged and fully applicable. The following Technical Specifications also remain unaffected and applicable: 3.3.3.2 -Remote Shutdown System *; 3.7.1 ' Emergency Service Water (ESW) System - Divisions 1 and 2'; 3.7A ' Control Room Heating, Ventilation, and Air Conditioning (HVAC) System'; and the Technical Specifications related to Sections 3.8 (Elec#ical Power Systems),3.5 (Emergency Core Coating Systems (ECCS) and Reactor Core Isolation Cooling (RCIC)

System) and 3.6 (Containment Systems),. On this basis, the margins of safety defined in the Technical Specifications remain unchanged.

T herefore, the changes associated with this license amendment request do not involve a .

significant reduction in the margin of safety.

)