JSP-614-92, Application for Amend to License NPF-62,revising TS 3/4.3.2, Containment & Rv Isolation Control Sys, to Provide Reasonable Period of Time to Detect & Correct Inoperabilities of Differential Temp Isolation Instruments

Application for Amend to License NPF-62,revising TS 3/4.3.2, Containment & Rv Isolation Control Sys, to Provide Reasonable Period of Time to Detect & Correct Inoperabilities of Differential Temp Isolation Instruments

ML20126B587
Person / Time
Site:	Clinton
Issue date:	12/15/1992
From:	Jamila Perry ILLINOIS POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20126B588	List: JSP-614-92, Application for Amend to License NPF-62,revising TS 3/4.3.2, Containment & Rv Isolation Control Sys, to Provide Reasonable Period of Time to Detect & Correct Inoperabilities of Differential Temp Isolation Instruments ML20126B612
References
JSP-614-92, U-602070, NUDOCS 9212220140
Download: ML20126B587 (10)

Text

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. l luno$ Pewor Company 1

• C'inton Powor Daton j P O Box 078 l

• Chnton. IL 61727 1 Tel 217 93b622G Fax 217 935-4032 J, stephen Perry Lu o V;e FMcont ILLINOIS EIkdlATEift Elj?9$'(12-15)-tP 8E.100a Docket No. 50 461 JSP-614-92 December 15, 1992 Document Control Desk Nuclear Regulatory Commission Washington, D.C. 20555

Subject:

Clinton Power Station Proposed Amendment of Facility Operatinn License No. NPF-62

Dear Sir:

Pursuant to 10CFR50.90, Illinois Power (IP) hereby applies for amendment of Facility Operating License No. NPF-62, Appendix A - Technical Specifications, for Clinton Power Station (CPS). This request consists of proposed changes to Technical Specification 3/4.3.2, " Containment and Reactor Vessel Isolation Control System." These changes are being proposed in response to an event which was reported in CPS Licensee Event Report 91 007, l These proposed changes will provide a reasonable period of time to detect and correct inoperabilities of differential temperature isolation instruments caused by air handling unit inoperabilities. In addition, these proposed changes will provide a reasonable period of time to perform preventive meintenance on those air handling units which are accessible during plant operation.

For each of these proposed Technical Specification changes, a description and the associated justification (including a Basis For No Significant Hazards Consideration) are provided in Attachment 2. Marked up copies of pages from the current Technical Specifications are provided in Attachment 3. In addition, an affidavit supporting the facts set forth in this letter and its attachments is provided in Attachment 1.

l IP has reviewed the proposed changes against the criteria of 10CFR51.22 i

for categorical exclusion from environmental impact considerations. The proposed changes do not involve a significant hazards consideration, or significantly increase the amounts or change the types of effluents that may be released offsite, nor do they significantly increase individual or cumulative occupational radiation exposures. Based on the foregoing, IP concludes the proposed changes meet the criteria given in 10CFR51.22(c)(9) for

a categorical exclusion from the requirement for an Environmental Impact Statement.

Sincerely yours, LA- ,

QjQ%] . S. Perr Senior V ce President 9212220140 921215 i PDR ADOCK 05000461 l p PDR

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l_ Attachments cc: NRC Clinton Licensing Project Manager i NRC Resident Office j NRC Region III, Regional Administrator

! Illinois Department of Nuclear Safety

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l STATE OF ILLINOIS l

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COUNTY OF DEVITT i

J. Stephen Perry, being first duly sworn, deposes and says: That i

he is Senior Vice President of Illinois Power Company; that the

application for amendment of Facility Operating License NPF 62 has q been prepared under his supervision and direction; that he knows

! the contents thereof; and that to the best of his knowledge and 1

belief said applicatien and the facts contained therein are true i and correct.

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DATED: This IF day of December 1992 i

Signed: .r-b)~l u )

tephen Perr -

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! Subscribed and suorn to before me this /8 day of December 1992.

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j . ', Attachmsnt 2 to U 602070 l LS92-002 Page 1 of 7 l 4

Background

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At approxi_.tely 0925 hours0.0107 days <br />0.257 hours <br />0.00153 weeks <br />3.519625e-4 months <br /> on December 12, 1991, with Clinton Power Station-

(CPS) at 100 percent power, the Shift Supervisor noted an increasing ambient 4

'.aa e urature trend in the 'B' (East) Reactor Water Cleanup (RWCU) Heat Exchar ger Room, as indicated on the equipment area ambient temperature l

. recorder (1E31-R608), while he was pointing out specific drywell temperatures to a plant engineer. The Shift Supervisor immediately checked the JC f' rer-ial temperature indication for the 'B' RWCU heat exahanger room by

' ec he equipment 'a differential temperature recorder (1E31-R6114, m -

1. r "cating zero. In response to this indication of a possible p'

.e leak detection system, the Shift Supervisor issued tr .o dispatch a non licensed operator to locally check the status

. of tne.t : andling unit for tb4.s area.

At 09' ' s, before the control room operators were able to dispatch a non-li- 1 ator to the area, the 'C' area non-licensed operator, conducting

a rov:. 4 .ainment tour, reported that the fan shaft in the 'B' RWCU heat excLer ger r,3m air handling unit (1 WOO 5SM) had apparently come out of its bearf-.g houssng. The Containment and Reactor Vessel Isolation Control Syster

(CRY;CS) differential temperature instruments monitor the inlet and outlet remperature of the cooling water vhich passes-through the cooling coils of th-ait handling unit. Tne setpoints for these instruments are-based on an assumed air handling unit heat removal rate. Because the air handling unit was no longer capable of removing heat at the assumed rate as ~a result of the

, fra shalt failure, both CRVICS differential temperature instruments for the

'B' RWC( heat exchanger room were declared inoperdh', and actions were initiated to comply with the CPS Technical Speci^ 'ons.

I Subsequent to the evei.. a res'ew of the strip chart from the equipment area differentia. remperaturo recorder concluded that the 'B' RWCU heat exchanger room sit undling unit fan had ' ailed at approximately 0700 hours0.0081 days <br />0.194 hours <br />0.00116 weeks <br />2.6635e-4 months <br /> on December i

12, 1491. fince the failed air ~.iandling unit was not recognized until approximately 0925 hours0.0107 days <br />0.257 hours <br />0.00153 weeks <br />3.519625e-4 months <br /> (approximately two hours and twenty-five minuter after the fan had c-rually failed) and the Technical Specifications require the affected systax is.lation valves to be closed within two hours, this event resulaec in operation prohibited by the plant's Technical Specifications.

This event was dccamented in CPS Licensee D.'ent Report (LER)91-007.

In response to the above event, Illinois Power (IP) is proposing changes to i

the CPS Technical Spec fications to allow a sufficient period of time to identify and correct inoperabilities of air handling units which support i

operation of the CRVICS differential temperature isolation instrumentation.

This proposed change will apply to those instruments which isolate one or more of the following systems: (1) Main Steam Lines, (2) RWCU, (3) Reactor Core Isolation Cooling (RCIC), and (4)' Residual Heat Removal (RHR). Since the' CPS Technical Specifications currently require a CHANNEL CHECK to be performed on i

these instrumsnts at least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />, IP believes that 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> will prostde a reasonable period of time to detect and correct inoperabilities of these instruments caused by air handling unit failures. In addition, this will provide a reasonable period of time to perform preventive maintenance on-those air handling units which are accessible during plant operation.

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Attachment 2 to U-602070 LS-92-002 Page 2 of 7 4-1 i

4 Description of Proposed Chances In accordance with 10CFR50.90, IP proposes to add an allowcnce to extend the

! allowable outage time (A0T) limit to repair CRVICS differential tempersture isolation instruments as required by CPS Technical Specification 3.3.2,

" Containment and Reactor Vessel Isolation Control System," to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, l provided sufficient ambient temperature isolation instruments for the j associated area are operable to initiate the associated isolation concurrent with a single failure. This proposed change would be applicable to those instruments which isolate one or more of the following systems

(1) main steam lines, (2) RWCU, (3) RCIC, and (4) RHR. The proposed allowance would be accomplished by adding a footnote to Action Statement 23 and a footnote to Action Statements 27 and 28 of Technical Specification Table 3.3.2-1, "CRVICS Instrumentation."

In addition, since all four CRVICS Main Steam Line Isolation, Main Steam Line Tunnel Differential Temperature isolation instruments monitor the same cooling l

water location, main. steam tunnel air handling unit failures could impact the operability of all four instruments concurrently. Co.sequently, IP is also proposing changes to Action b.3 of Technical Specification 3.3.2 such that this Action Statement will apply to inoperability of three or four CRVICS Main Steam Line Isolation Trip Function channels, rather than just three of one four channels.

The proposed changes identified above are indicated on the marked-up copies of CPS Technical Specifications 3/4 3-11 and'3/4 3 19 which are provided.as pages

, 1 and 8 of Attachment 3 of this submittal. The remaining pages of Attachment

! 3 are provided for informational purposes only.

Justification for Proposed Chances

) The CRVICS instrumentation channels affected by this proposed change are

associated with the leak detection system. As described in Section 7.6.1.4 of the CPS Updated-Safety Analysis Report (USAR)*, the purpose of the leak detection system instrumentation and controls is to monitor leakage from the reactor coolant pressure boundary and initiate alarms and/or an isolation function before predetermined temperature limits are exceeded. Pursuant to chis purpose, this instrumentation is designed to detect and effect an automatic isolation in response to a 25-gallon-per-minute (gpm) equivalent-steam leak in the particular srea beirg monitored.

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• The leak detection instrumentation associated with the main steam lines, the RWCU system, and the RHR system is also discussed in CPS USAR Sections 7.3.1.1.2.4.1.3, 7.3.1.1.2.4.1.10, and 7.3.1.1.2.4.1.11, respectively.

Attachmant 2 j to U-602070 LO 92 002

, , Page 3 of 7 i

As described in CPS USAR Section 5.2.5, the equipment areas in the auxiliary building, the main steam tunnel and the turbine building are monitored for primary coolant leakage. The process piping for each system monitored is

, located in compartments or rooms which are separate from other systems-, where feasible, so that leakage may be detected by area temperature instrumentation.

, Ambient temperatures of the equipment areas are monitored by dual-element j thermocouples. As stated above, individual area differential temperatures are monitored by temperature elements which sense the differential temperature

between the cooling water inlet and outlet of the respective area coolers.

. These monitors have sensitivities suitable for detection of reactor coolant 4 leakage into the monitored areas of 25 gpm (steam equivalent) or less. The 4

actual temperature trip setpoints are a function of room size and the type of ventilation provided, i In addition to temperature monitoring, excess reactor coolant leakage external-to the reactor containment building can be detected by low reactor water level, high process line flow, .and high differential flow._ The leakage detection methods used at CPS are summarized on CPS USnR Tables 5.2-9a and

5.2 9b. As can be seen from these tables, two or more leakage detection

! systems sre available for each system or area that is a potential source of leakage. Further, accessible areas are inspected periodically, and the

temperature and flow indications are monitored regularly. Any instrument j indication of abnormal leakage is investigated.

With respect to area differential temperature monitoring, the cooling water supply and isolation provisions are described below for the main steam _ tunnel,

RWCU r i rooms, RWCU heat exchanger rooms, RCIC equipment room and RER heat exchanger rooms. Each area is addressed separately.

Main Steam Tunnel The Plant Chilled Water System (WO) supply to thejfour main steam tunnel area air handling units' cooling colla is arranged in parallel. The I

inlet cooling temperature is monitored by four separate temperature elements (lE31-N029A-D) located in the common cooling water supply line i prior to the line branching to supply the four separate air: handling units (1 WOO 4SK-N). Similarly, the outlet cooling water temperature is monitored by four separat- temperature elements (1E31-N030A-D) located in-the common cooling water return line after the four separate air handling unit cooling water return lines are rejoined.

Temperature elements 1E31-N029A-D and 1E31-NO30A-D provide input to

temperature switches (trip modules) 1E31-N605A-D. These temperatura, switches are arranged in a.two-out-of-four logic configuration for-isolation of the main steam lines and drains. A trip of either temperature switch 1E31 N605A or B also pravides an isolation signal _to the RWCU suction and reture line containment isolation valves.

Additionally, temperature elements 1E31-N029A and 1E31-NC30A provide input to another teugerature switch,-1E31-N605E. Simile ly, temperature-elements 1E31-N0298 and 1E31-N030B provide-input to_ temperature switch t

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Attachment 2 to U-602070 LS-92-002

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1E31-N605F. A trip of either of these latter two temperature switches

provides an isolation signal to the RCIC suction and steam supply line i containment isolation valves.

RUCU Pump Rooms - A. B. C The Plant Chilled Water System (WO) supply to the area air handling unit

cooling coils for each of the RWCU Pump Rooms (one air handling unit serving each room) is monitored by two separate temperature elements.

The chilled water supply to the air handling unit (1 WOO 4SF) for Room 'A' is monitored by temperature elements 1E31 N038A and B; Room 'B' (air

handling unit 1 WOO 4SE) is monitored by temperature elements 1E31 N041A and B; and Room 'C' (air handling unit 1 WOO 4SC) is monitored by temperature elements 1E31 N038E and F. Similarly, the chilled water l return lines are monitored by two separate temperature elements

1E31-NO39A and B for Room 'A', 1E31-N042A and B for Room 'B', and 1E31-NO39E j and F for Room 'C'.

i Temperature elements lE31-NO38A and B, and 1E31-NO39A and B provide input to temperature switches 1E31-N613A and B, respectively.

Similarly, temperature elements 1E31-N041A and B, and 1E31-N042A and B

[ provide input to temperature switches 1E31-N614A and B; temperature elements 1E31-N038E and F, and 1E31 N039E and F provide input to temperature switches 1E31-N613E and F. A trip of any one of these temperature switches will result in automatic closure of the RWCU suction and return line containment isolation valves.

! RUCU Heat Exchanner Rooms - East. West I

The Plant Chilled Water System (WO) supply to the area-air handling unit cooling coils for each of the RWCU Heat Exchanger Rooms (one air i

handling unit serving each room) is monitored by two separate temperature elcments. The chilled water supply to the air handling unit

, (1WOOSSM) for RWCU Heat Exchanger Room - East is monitored by-terperature elements lE31-N053A and B; RWCU Heat Exchanger Room - West (air handling unit 1WOOSSN) is monitored by temperature elements 1E31-NO35A and B. Similarly, the chilled. water return lines are monitored by i

two separate temperature elements;_1E31 N054A and B for RWCU Heat

! Exchanger Room - East, and IE31 NO36A and B for RWCU Heat Exchanger Room l - West.

Temperature elements 1E31-N053A and B, and lE31-N054A and B provide f input to temperature switches 1E31-N618A and-B, respectively.

Similarly, temperature elements 1E31-NO35A and B, and 1E31-N036A and B 4 _p rovide input to temperature switches 1E31-N612A and B. A trip of any one of these temperature switches will result in automaticLclosure of the RWCU suction and return line containment isolation valves.

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Attachment 2 j ',

• L to U-602070 1

-LS92-002 Page 5 of.7 I

i RCIC Eauipment (Pumo) Room The Shutdown Service Water System (SX) supply:to the area air handling-

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l unit (1VYO4S) cooling coils for the RCIC Equipment (Pump) Room is monitored by two separate temperature elements 1E31 N005A and B.

. Similarly, the. SX return line is monitored by two separate temperature

elements 1E31 N006A and B. These temperature elements. provide input to temperature switches 1E31-N603A and B. A trip.of either one of these temperature. switches will result in automatic closure of the RCIC suction and steam supply line containment isolation valves,

EllR Heat Exchanger Rooms - A. B

[ The Shutdown Service Water System-(SX) supply to the area air handling 3

unit cooling coils for.each of the RHR Heat Exchanger. Rooms (one air handling unit serving each room) is monitored by two separate temperature elements. 'The SX supply to the air handling unit-(1VYO3S) for Room >A' is monitored by temperature-elements 1E31 N027A and B, and

! for Room 'B' (air handling unit IVYOSS) is monitored by temperature j elementsL1E31-N002A and B. Similarly, the SX return lines.are monitored by two separate temperature elements 1E31-N028A and B for Room 'A(,.and

[ 1E31-N003A and B for Room 'B'.

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Temperature elements 1E31-N027A and B, and 1E31-N028A and B provide l- input to-temperature-switches 1E31-N600A and B. Similarly, temperature

!- elements-1E31-N002A and B, and 1E31'-N003A and B provide input to temperature switches 1E31-N611A and B.

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l A trip'of any one of-these-L temperature _ switches will result in automatic closure of the RCIC suction-and. steam supply containment isolation valves and the-RHR return-to-teedwater, shutdawn. cooling-suction, fuel pool cooling assist, j and' reactor, vessel head-spray line containment isolation valves, j Supportine Justiffcation.

i-The primary justification for the proposed changes is based on' the requirement :

l that a minimum: number of ambient temperature isolation instruments.in the

, associated area remain operable during the extended time period when l- differential temperature instruments are: inoperable. For inoperable p differential temperature isolation. instrumentation-associated with the RWCU,c j RCIC, and/or RER. systems, both-ambient temperature isolation instruments-(one' '

in each.. Trip-System) for the affected area would be'. required operable during.

j_ the proposed-time extension.-

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- For inoperable differential: temperature isolation instrumentation associated

with the main steam lines (for which two-out-of-four~ logic is? utilized),7at

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least;two ambient temperature isolation instruments for the main steam ~ tunnel would be' required to be. operable during the proposed Action time extension.

p . Although a failure of one of the two operable ambient temperature _ isolation 3-instruments could preclude' initiation of the-isolation signal, Action Statement b.2 for the.two inoperable' ambient temperature instruments would require one of' them to be placed into the tripped condition within one hour.

l -(IP has proposed:that this time limit be increased to six hours in letter U- t 601871. dated September 20,-1991,- based on reliability analyses performed by; j' -

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, Attachmsnt 2 4

to U 602070 1

LS-92-002 Page 6 of 7 3 the Boiling Water Reactor Owners' Group.) Since the minimum time currently allowed under Action Statement 23 is six hours, one inoperable ambient temperature isolation instrument channel would be required to be placed into the tripped condition prior to the proposed time extension taking effect. As 4 a result, the two channels required operable by the proposed footnote "*" and the requirement to place one inoperable channel into the tripped condition will ensure that the capability to initiate main steam line isolation in response to a high main steam tunnel temperature condition will be maintained during the proposed time extension, even in the event of a single failure.

The setpoints for the ambient temperature instruments were calculated assuming i the associated air handling unit ie in service during winter conditions (i.e.,

i low ambient temperature). As a result, an isolation signal will be generated 1

in response to high ambient temperature in the event of a 25-gpm equivalent steam leak under all cooling conditions. In addition, because redundant j ambient temperature switches are required to be operable for each of the

affected areas during the extended time period, the isolation signal will be

generated even in the event of a single failure. With the associated air handling unit out of service, the ambient temperature would increase at a faster rate and, therefore, isolation would occur sooner than assumed in the

! ambient temperature instrument setpoint calculations. (It should be noted l that, as part of a monitoring program, IP. monitors the temperature of plant r

areas which contain equipment required for safe shutdown and will evaluate the impact of elevated ambient temperature on the equipment qualification of that equipment. As a result, any impact on the environmental qualification of equipment required for safe shutdown will be identified and evaluated in the event of elevated ambient temperatures caused by loss of an air handling unit.)

, With respect to Action Statement b.3, the proposed changes do not involve a

condition less safe than currently allowed by Action b.3. As the logic for isolation of the main steam lines is two-out-of-four, loss of four channels for a Trip Function is functionally equivalent to loss of three channels for that Trip Function. In addition, the proposed change avoids an unnecessary entry into TS 3.0.3 and associated plant shutdown when either three or four channels for a Trip Function are inoperable, i

Basis For No Sienificant Hazards Consideration In accordance with 10CFR50.92, a proposed change to the Operating License (Technical Specifications) involves no significant hazards consideration if operation of the facility in accordance with the proposed change would.not:

! (1) involve a significant increase in the probability or consequenceslof any-accident previously evaluated, or (2) create the possibility of a new or different kind of accident from any accident previously evaluated, or (3) involve a significant reduction in a margin of safety. The proposed changes are evaluated against each of these criteria below:

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(1) The differential temperature instruments involved in these proposed changes are not assumed to function to mitigate any accidents described in Chapter 6 or 15 of the CPS Updated Safety Analysis Report (USAR). As a result, the proposed changes cannot increase the conseq.ences of any accident previously evaluated. The ambient and differential temperature instruments are provided only to detect and initiate isolation of a 25-gpm equivalent steam leak. Although the proposed changes will allow a loss of diversity for mitigating the effects of a 25 gpm aquivalent steam leak for a limited period of timo, this loss or diversity would be l allowed only when sufficient ambient temperature isolation I"atruments for the associated area are operable to initiate the associaten isolation concurrent with a single failure. As a result, automatic isolation of a 25-gpm equivalent steam leak will still occur, even in the event of a single failure. The consequences of a 25-gpm equivalent steam leak will thus not be increased by these proposed changes. In addition, these proposed changes do not affect those factors which can

, initiate a line break. As a result, the probability of a line break or 3 a 25-gpm equivalent steam leak occurring will not be increased by these proposed changes. Therefore, these proposed changes will not increase the probability or the consequences of any accident previously evaluated.

. (2) The proposed changes do not result in a change to the plant design. As

a result, no new failure modes are introduced. Therefore, the proposed changes ccanot create the possibility of a new or different kind of accident from any accident previously evaluated.

I (3) The differential temperacure instruments involved in these proposed changes are not assumed to function to mitigate any accidents described

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in Chapter 6 or 15 of the CPS USAR. These differential temperature instruments (in conjunction with the ambient temperature instruments) are provided only to detect and initiate isolation of a 25-gpm equivalent steam leak. The proposed changes will allow a loss of diversity for mitigating the effects of a 25-gpm equivalent steam leak for a limited period of time. However, the capability to isolate such a leak, even in the event of a single failure, would continue to be 4 maintained by the ambient temperature instruments required to be

operable during this extended time period. The proposed time limit permits a reasonable period of time to detect and correct problems with area unit coolers without requiring an unnecessary plant shutdown (transient). In addition, these proposed changes-do not affect the setpoints of these ambient temperature isolation instruments. As a result, the associated automatic actions will occur as assumed by plant design. Further, an established IP program will ensure that the ambient temperature of plant areas are monitored and the impact on environmental qualification.of equipment needed for safe shutdown is evaluated in the event of elevated area temperatures caused by -loss of. an air handling unit. Therefore, these proposed _ changes-will not result in a significant reduction in-the margin of safety.

r Based upon the foregoing, IP concludes that these proposed changes do not involve a significant hazards consideration.

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