ML20126H434

Requests Exemption from 10CFR50.48,App R Requirements Until 1986 Refueling Outage to Complete Mods for Safe Shutdown. Fire Watch Designated as Compensatory Measure Can Be Satisfied by One Roving Watch

ML20126H434
Person / Time
Site:	Cooper
Issue date:	06/07/1985
From:	Pilant J NEBRASKA PUBLIC POWER DISTRICT
To:	Vassallo D Office of Nuclear Reactor Regulation
References
NUDOCS 8506180344
Download: ML20126H434 (12)

Text

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Nebraska Public Power District " '" "?ahok5fshetet' ' '"

S June 7,1985 Director, Nuclear Reactor Regulation Operating Reactors Branch No. 2 Division of Licensing U. S. Nuclear Regulatory Commission Washington, D.C. 20555 Attention: Mr. Domenic B. Vassallo, Chief

Subject:

Appendix R - Schedular Exemptions; Request for.

Reference:

1) Letter from J. M. Pilant to D. B. Vassallo dated May 9,1985, " Appendix R, Analysis of Cooper Nuclear Station"

Dear Mr. Vsssallo:

Nebraska Public Power District has completed a detailed analysis and verification walkdown to ensure that adequate circuit separation exists between the redundant capabilities required to safely shut down the Cooper Nuclear Station in the event of a fire. This analysis and walkdown confirmed what was reported in Reference 1, that some areas did not meet the technical requirements of 10CFR50, Appendix R, Section III.G.2. The District has been diligent in performing modifications to correct these discrepancies during the present refueling outage; however, due to factors described in the attachment, the District does not believe all of the modifications can be completed by plant start-up currently scheduled for late July, 1985. A conference call with the staff on May 20, 1985, discussed the proposed corrective modifications, reasons for schedular extension, and compensatory measures planned for these areas.

Also discussed was the District's proposal to use the Automatic m,x c Depressurization System (ADS) and the Core Spray S@@ System (CSS) to achieve safe shutdown for certain plant areas.

88 en mo Based upon these discussions, the District respectfully requests, pursuant to 10CFR50.12, a specific exemption from the schedular y requirements of 10CFR50.48(c). Specifically, an extension until no the 1986 refueling outage (approximately September 1986) is

@@ requested for the modifications described in the attachment.

g The District believes the fire watch designated as the om compensatory measure for three of the exemptions can be

@@g satisfied by one roving watch. This roving watch would tour each of the fire areas, at least three times a hour. A floor plan 606 R a wIoa amo'+m si, 5 $/50-

. Mr. Dom:nic B. Ver::cIlo P:go 2 June 7,1985 of the areas to be covered by the watch is included in the attachment , and a time-motion study will be performed to demonstrate its feasibility.

As described in Reference 1, the District identified several areas where safe shutdown methodologies identified in previous submittals could not be used and proposed using the ADS and CSS to achieve safe shutdown. The District requests an exemption from the requirement of 10CFR50, Appendix R, Section III.L.2(b) in the event that the use of the ADS and CSS results in a brief period when the upper region of the reactor core is uncovered. This is discussed further in Exemption No. 6 in the attachment.

The District is committed to achieving full compliance with Appendix R requirements at the earliest possible date. The exemptions specified in this letter are requested because the possibility of their respective modifications being completed by start-up is in doubt. Every effort is being made to complete as many modifications as possible before that time; hence, it is expected the final numbers of schedular exemptions to Appendix R actually required may be less than specified in the attachment.

In accordance with 10CFR170.12(c) an application fee of $150 is enclosed.

Sincerely, M. ilant eVf Technical Staff Manager Nuclear Power Group JMP:dmr10/1(DAILY 1)

Attachments 4

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Exemption No. 1

Description:

Provide new power feeder to Diesel Generator No. 2 exhaust fan.

Justification:

Fire in the Auxiliary Relay Room (already designated an Alternate Shutdown Area) or the 882' level of the Control Building has the potential to damage both MCC "LX" and "TX" and/or Feeder Cables MLX39 and MTX7 to MCC DG-1 and DG-2 respectively. The DG Room exhaust fans and HVAC units for the individual DG Rooms are fed from these MCC's. The diesel generators may not be capable of running for eight hours without ventilation due to excessive heat build-up.

Proposed Modification:

The modification is to provide an alternate power supply to the exhaust fan and associated heating and ventilation controls during the DG Operation. This modification will eliminate all outside power cables (except 125VDC control power which is wrapped) from all fire areas of concern.

Reason for Exemption:

Components necessary for this modification must be purchased to a Class 1E specification, which has resulted in a delivery lead time past the start-up '

date for the 1985 outage. This modification will be installed during the 1986 outage due to delivery and material qualification problems and the desire not to enter a limiting condition for operation (LCO) on the diesel generator in question during plant operation.

Compensatory Action:

Fire watch on the 882' level of the Control Building or interim repair procedure.

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Exemption No. 2

Description:

Provide additional (back-up) source of gland seal water for service water pump bearings.

Justification:

Fire in Auxiliary Relay Room (already designated an Alternate Shutdown Area) or the 882' level of the Control Building has the potential to damage both MCC "LX" and "TX" and/or Feeder Cables "MLX51 and MTX28 to Starter Racks LZ and TZ respectively. The service water gland seal pumps are powered from Starter Racks LZ and TZ. The service water pumps would be subject to bearing failure without gland seal water.

Proposed Modification:

The modification is to provide a back-up seal water supply to the service water pumps through a one-inch pipe from the existing 12-inch diameter fire protection piping in the Service Water Pump Room. The new one-inch diameter piping will be isolated through a check valve and connect up-stream of the existing pressure control valve of the gland seal-water supply. The back-up gland seal water will be normally isolated by a closed solenoid valve. A flow sensing device will be located downstream of the check valve to detect flow.

The solenoid valve will fail open and provide water to the service water pumps if the power supplies to the gland seal pumps are lost.

Reason for Exemption:

The proposed work cannot be done this outage due to the magnitude of the existing work (IGSCC, EQ, PMIS, other Appendix R items) in progress and the resultant manpower restraints.

Compensatory Action:

Fire watch on the 882' level of the Control Building.

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Exemption No. 3

Description:

Reroute Conduits V3, Vil, and V13 and upgrade RPS Room IB to three-hour fire area.

i Justification:

The safe shutdown system instrument loop power supplies are powered from Critical Power Panels CCP1A, CCPIB, and CPP which are powered from Critical

' Distribution Panels CDPIA and CDPIB. These instrument loops are required for the operation of the individual systems from the Control Room. Cable V3 is the power feeder from CDPlA to CPPIA; Cable V11 powers CPP from CDPIB and V13 powers CPPIB from CDPIB. A fire in the Control Building basement (882' level) i or 903' level hallway has the potential to disable the power feeds to the Division-I 'lF' ' Bus and Cables Vil and V13 which power the Division II critical instrumentation ~(CPP and CPPIB). This in effect disables one whole division of equipment and the instrumentation for the other division.

The feeder for CCPlA (V3) currently is routed through a portion of the IB Battery Room. A fire in the IB Battery Room has the potential to disable the Division 'II DC Bus along with some Division I instrumentation.

Proposed Modification:

Conduits V3, -Vil, and V13 will be rerouted from the fire area of concern. .V3 will be rerouted up through the floor of RPS Room 1A and then through the Cable Spreading Room to CCPlA. Vll and V13 will be rerouted up'through floor of RPS Room IB and then through the Cable Spreading Room to CCPIB. The walls j, of RPS Room IB will be upgraded to three-hour fire barriers and the door between RPS Rooms lA and IB will be replaced with three-hour rated door or

! eliminated.

Reason for Exemption:

. 'The materials necessary for implementation of this design change have been l ordered; however, the estimated delivery dates may not allow the modification to i be completed before start-up.

Compensatory Action:

Fire watch in Control Building 903' level corridor, RPS Rooms lA and IB and Battery Room IB.

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Exe=ption No. 4

Description:

Provide circuit isolation switches for HPCI Interlock Cables HP68, HP186, and EP106. Provide circuit isolation switches for Breaker Interlock Cables H432 and H433. Provide circuit isolation switches for Diesel Interlock Generator Cables DG20 and DG54.

Justification:

A fire in specific locaticus on the 903' and 931' levels of the Reactor Building would prohibit use of the EPCI Systen to safely shut down plant due to the current routing of Cables EP68, EP186, and HP106. A fire in the Critical Switchgear Roon IG fails the Division II equip =ent. The isolation switch for Cables H432 and H433 vill ensure that Breaker "1FA" (the tie breaker between Critical Bus IF and Non-Critical Bus lA) vill not close due to a fire in Svgr. Roo= IG. Cables DG20 and DG54 are the interlock cables for the respective diesel generator output breakers. A single fire has the potential to fail both cables.

Proposed Modification:

The modification for the three listed interlock cable proble=s is to install isolation switches for each circuit using the guidelines for these switches as established in Generic Letter 81-12.

A. The HPCI Interlock Cables will have isolation switches installed in the Auxiliary Relay Roo=.

B. The Breaker 'lFA' interlock cables will have isolation switches installed in Critical Switchgear Room IF.

C. The diesel generator breaker interlock cables vill have isolation switches installed in their respective diesel generator roo:s.

Reason for Exemption:

These codifications involve CNS safety systems and have the potential to cause unreviewed safety questions. These modifications cust be fully reviewed and the proposed work cannot be done this outage due to the magnitude of the existing work (1GSCC, EQ, PMIS, other Appendix R ite=s) in progress and the resultant manpower restraints.

Cocpensatory Action:

An interim procedure vill be written to facilitate cutting the affected diesel generator and HPCI Interlock Cables. A separate intertn procedure vill provide for manual operation of the Division I, Critical Bus IF, Breaker "1FA" locally by pulling the control power fuses and manually operating breakers.

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Exemption No. 5

Description:

Replace specific fire doors due to re-evaluation of CNS fire areas and provide documentation and labeling for existing fire doors.

j - Justification:

As a part of overall CNS Appendix "R" Compliance Program and specifically the cable separation analysis, new fire areas have been established within the

- Control Building. The Relay Room, Battery Rooms lA and IB, DC Switchgear Rooms lA and IB, and Reactor Protection Room IB have been established as i individual fire areas and require three-hour rated fire barriers.

Proposed Modification:

Inspect and/or replace fire doors (if necessary) l4 A. RPS Room "B" to Control Building corridor.

B. D.C. Swgr. Room "B" to Control Building corridor, i C. D.C. Swgr. Room "A" to Control Building corridor.

D. Battery Room "B" to Control Building corridor.

E. Battery Room'"A" to Control Building corridor.

) F. West Doors. Relay Room to Control Building corridor.

G. East Doors Relay Room to Control Building corridor.

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[ Provide documentation to ensure correct rating for remaining fire doors, door frames, and closers.

Reason for Exemption:

Long lead times for delivery of non-standard sized three-hour rate fire doors, t

Compensatory Action:

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Fire watch on the 903' level of the Control Building.

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Exemption No. 6 Basis for Request The District has identified certain plant areas where safe shutdown will be achieved by the use of the Automatic Depressurization System (ADS) in conjunction with the Core Spray System (CSS). Reference (1) indicates that this strategy may result in a short-term uncovering of the upper portion of the reactor core during depressurization.

Background

Previous NRC generic analysis (Reference 2) of similar methodology indicated that the uncovering time is short enough and the amount of fuel uncovered is small enough that cladding integrity would not be threatened.

Since the issuance of Reference 3, the District has identified the plant areas where the ADS and the CSS will be utilized to achieve safe shutdown. These areas are listed in Table 1. The separation analysis performed by the District has identified all safe shutdown cables and components that would be potentially affected by a fire in these areas. The analysis has concluded that the ADS and the CSS are adequately separated in these areas.

The District has initiated an analysis of the Cooper Nuclear Station to determine if the reactor core will be uncovered and the length of the duration of any uncovering. Based on an analysis (Reference 4) conducted for a plant similar to Cooper, the District believes that core uncover will probably not occur during depressurization. The analysis of Cooper will be completed by the end of June, 1985. However, in the event that the analysis shows that core uncovering would occur, the District is requesting the following exemption.

Exemption Request Under the guidelines of 10CFR50.12, the District requests an exemption from the requirements of 10CFR50, Appendix R, in the event that the use of the ADS and the CSS results in a brief period when the reactor core is uncovered.

This event has been previously analyzed and accepted by the NRC and thus does not involve any unreviewed safety issues and does not adversely affect the health and safety of the general public.

Specifically, an exemption is requested from the system limitations prohibiting uncovering of the core.

REFERENCES

1. NEDO 24708A, " Additional Information Required for NRC Staff Generic Report on Boiling Water Reactors", Revision 1, December, 1980.

2. NRC Memorandum to R. J. Mattson from L. S. Rubenstein, "Use of the Automatic Depressurization System (ADS) ~ and Low Pressure Coolant Injection (LPCI) to Meet Appendix R, Alternative Shutdown Goals, December 3, 1982.

3. NPPD letter Pilant to Vassallo, " Appendix R Analysis of Cooper Nuclear Station," dated May 9, 1985.

4. NEDC 30291, " Alternate Shutdown System for Monticello Nuclear Generating Plant, Northern States Power Company," December, 1983.

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TABLE 1 i

! - Control Building'877', 882', and 903' Elevations Battery-Room 1A i

l Battery Room IB I.

i Diesel Generator IB Reactor Building 903' Elevation (except Northeast Corner)

Reactor Building 931' Elevation, North and Northwest Sections Turbine Building j

i 1  !

I 4

3 3

4 4

).

I h '

e t

i 4

4 4

4 V

f

FIRE WATCH PATH FOR EXEMPTIONS No. I a 2 n

5

=

g STAIRWAY TO 903' LEVEL a =

'o 5 t

2 I m

( = J m_ 72' -O" CONTROL BUILDING ELEV. 88 2'- 6"

~+-

saTCn Oven FIRE WATCH PATH

= ewe FOR EXEMPTIONS No. 3 a 5

~

(- . -

e u -

(

d~

E 5

AUX. 5 RELAY ROOM q7 g E

=

E

- 5 E

5 L -

9 ION SYSTEM g

ROOMIB -

l REACTOR -

- DC SWGR PROTECTION SYSTEM ROOM 18 ROOM IA ,, .

EERGY INSTRUMENT REPAIR ROOM DC WGR LJ

/ BATTERY ROOMIA 1f

, 7f - 0" .

CONTROL BUILDING ELEV. 903'-6"