ML20091E427

Forwards Summary of Fire Protection Review to Determine Conformance of Facility to Section Iii.G of 10CFR50,App R, Per 840427 Commitment.Fire Protection Provisions Adequate

ML20091E427
Person / Time
Site:	Fort Saint Vrain
Issue date:	05/11/1984
From:	Brey H PUBLIC SERVICE CO. OF COLORADO
To:	Johnson E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
References
P-84142, TAC-54373, NUDOCS 8406010244
Download: ML20091E427 (13)

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a public Service Company Cf Odendro b,

0<h 2420 W. 26th Avenue, Suite 1000 Denver, CO 80211 4

May 11, 1984 Fort St. Vrain Unit No. 1 P-84142

%]@]33 Mr. Eric H. Johnson Reactor Project Branch Chief e

Region IV L

Nuclear Regulatory Comission Wl5W 611 Ryan Plaza Drive j

Suite 1000 Arlington, Texas 76011 DOCKET No: 50-267

SUBJECT:

10CFR50, Appendix R Fire Protection Review

REFERENCE:

PSC Letter 0.R. Lee to J.T. Collins Dated March 2, 1984 (P-84071)

Dear Mr. Johnson:

Enclosed is a sumary of the Fire Protection Review (FPR) performed by the Public Service Company of Colorado (PSC) staff under the guidance of a Fire Protection En conformance of Fort St. Vrain (FSV) gineering Consultant to determine to Section III.G of 10CFR50, Appendix R.

The sumary is being submitted in response to a commitment made during the April 27, 1984' meeting with the NRC concerning Appendix R.

The complete FPR is in the form of notes and working documents which are also available for your review.

Separate correspondence concerning emergency lighting at Fort St. Vrain will be forwarded in the near future.

Based on the results of the FPR, PSC remains convinced that the fire protection provisions at Fort St. Vrain are adequate to protect the health and safety of the public in the event of any accident involving a postulated fire of maximum credible size. Application of 10CFR50, Appendix R to FSV for the purpose of performing the FPR required some interperative latitude due to the unique design and licensing characteristics of this plant.

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j We look-forward to working with you in resolvin Please feel-free to contact either Mr. J.R. Reesy (303)g this issue.

571-8406 or myself (303)_571-8404 should any questions arise.

Very truly yours, f

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1 H. L. Brey, Manager Nuclear Engineering Division HLB:pa Attachment i

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Attachment to P-84142 Page 1 Fire Protection Review Summary Introduction A Fire Protection Review (FPR) was performed in support of the conclusions contained in PSC's Appendix R exemption request letter P-84071, Lee to Collins, dated March 2, 1984. The purpose of the FPR was to determine whether the fire protection provisions at Fort St.

Vrain were adequate to protect the health and safety of the public.

SectionIII.GofAppendixRtofl0CFR50andsupplementary information received during the associated on-site NRC audit (August 22-26,1983) were used as criteria during the course of the FPR.

Definition of Required Functions Performance of this FPR required, in part, an evaluation to determine Fort St. Vrain's ability to be shut down and cooled down regardless of any single fire. This plar.t has been licensed with an extensive array of systems and equipment whose purpose is to safely shut down/ cool down FSV in the event of any postulated accident. As part of the FPR, functions were identified which are required in order to protect the health and safety of the public. The plant was then evaluated.to confirm that at least one system would be available i

to perform each function regardless of'any single postulated fire at FSV.

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e Attachment to P-84142 Page 2 The required functions are identified below:

1)

Control core reactivity, 2)

Maintain PCRV integrity, 3)

Depressurize the core (2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> after fire),

4)

Maintain adequate PCRV liner cooling (continuous cooling even though the FSAR allows interruption for 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />),

5)

Assure that the public health and safety consequences analyzed and presented in Design Basis Accident 1 (DBA-1) of 4

the FSAR are not exceeded. DBA-1 involves a Loss of Forced' Cooling (LOFC).

Systems

' Required

-for Fire Protection Review Shutdown /Cooldown Functions Portions of the following systems were identified as containing equipment required to perform the Fire Protection Review i

shutdown /cooldown functions:

i System 12 - Control Rods / Drives and Reserve Shutdown System

.i i-System 23 - Helium Purification System System 25 - Liquid Nitrogen System System 41 - Circulating Water System System 42 - Service Water System

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Attachment to P-84142

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+3 Page 3 System 46 - Reactor P) ant Cooling Water System

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System 47'- Purification Cooling Water system System 73 - Reactor Plant Vent lation System A

Each system is discussed separately below:

System 12 This system is required to control core reactivity. This can be accomplished by either inserting the Control Rods into the core or by activating the Reserve Shutdown System.

During LOFC conditions, both actions are initiated to assure reactivity control.

System 23 The portion of this system that provides a path through one of the two helium purification trains and then to the Reactor Plant Ventilation System was identified as being required during depressurization. Depressurization does-not have to be initiated until 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> following the LOFC.

System 25 The Liquid Nitrogen Storage Tank, T-2501, and the supply lines from that tank to the Low-Temperature Adsorbers in the Helium Purification System were identified as being required for the Fire-Protection Review shutdown /cooldown..This equipment would provide the cooling required during depressurization of the primary coolant.

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Attachment to P-84142 Page 4 System 41 The portion of this system identified as being required in connection with a Fire Protection Review shutdown /cooldown, is any one of the three Circulating Water Make-up Pumps and the piping to the Service Water Cooling Tower Basin.

This equipment would be capable of continuously making up water to the Service Water System.

System 42 Any one of three Service Water Pumps and related piping is required to provide cooling water to the Reactor Plant Cooling Water Heat Exchangers.

During the Fire Protection Review, it was assumed that the Service Water System would operate as a once-through cooling system, and no credit was taken for continued operation of the Cervice Water Cooling Tower.

System 46 Any one of the four Reactor Plant Cooling Water Pumps is required in the Fire Protection Review shutdowa/cooldown to provide the needed PCRV liner cooling. This system operates as a closed loop using the selected Reactor Plant Cooling Water Pump and its associated piping, Reactor Plant Cooling Water Heat Exchanger, liner cooling tubes, and surge tank from which the pump obtains its suction. The piping which allows ~this system to supply cooling to the Purification Cooling Water Heat Exchangers and to the High Temperature Filter /Adscrbers in

Attachment to P-84142 Page 5 the. Helium Purification system is also required for the Fire Protection Review shutdown /cooldown.

1-System 47 The portion of this. system which supplies cooling water to the Helium Purification Coolers is required only during depressurization of the primary coolant. Either one of'the two redundant Purification Cooling Water Pumps along with its associated Purification Cooling Water Heat Exchanger and supply / return -piping through the Helium t

Purification Cooler is required.

System 73 During primary coolant depressurization one Reactor Plant.Exniust Fan and Filter is required. This includes the associated ductwork and the Reactor Plant Exhaust Stack.

Fire Protection Review Procedure 4

l After.

the portions of the systems required for 'the Fire Protection Review shutdown /cooldown were identified, they _ were reviewed -to. determine if a single fire would have the ability to disable redundant components'and/or-prevent shutdown /cooldown of FSV.

This was accomplished by determining which components-in the required

. systems could'be disabled by a single fire..

It.was-assumed that' mechanical components with internal water flow would not. be damaged V

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Attachment 'n P-84142 Page 6 even if located in the fire zone, and credit tras taken for valves remaining in their normal operating mode when the normal operating mode was the same as the loss-of-power failure mode. After locating

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the components and associated cables on drawings, an evaluation was performed and a determination made whether a single fire could prevent redundant components from performing the required function.

I This determination was made using the following separation criteria:

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1) Do redundant components exist which can perform each selected function and are they. separated by a 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> fire' barrier?

NOTE:

A 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> barrier was considered to be concrete with a 4

thickness of at least 5-1/2" 'or block wall with a thickness of at least 6".

The barrier need not be-totally enclosing but must completely divide any 20 foot diameter sphere which can encompass both pieces of equipment.

2)

If the' redundant components do not meet criteria 1) above, do they meet both of.the following criteria (a&b)?

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a)

Must meet one of the following:

1)

Components are separated by.20 feet with no intervening combustibles.

NOTE:

'No 20L foot:. diameter-sphere will. encompass both components.and. associated' cables'

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Attachment to P-84142 Page 7 one component is above the other, the effects of rising heat will be analyzed.

ii) Components are separated by a one hour fire barrier.

NOTE:

A 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> barrier was considered to be concrete with a thickness of at least 3-1/2" or block wall with a thickness of at least 3".

The barrier need not be totally enclosing but must completely divide any 20 foot diameter sphere which can encompass both pieces of equipment.

b)

In addition ~ to 2a), the entire area containing the components must be protected with automatic fire detection and suppression.

NOTE:

Iftheseparationcriteriain2a)wasmetbut area-wide automatic detection and suppression d

were not

present, the fire load of combustibles in the postulated fire vicinity was reviewed.

These fire loads were documented to the NRC via PSC letter P-78182, Fuller to Gammill, dated November 13, 1978.

.If the fire load was sufficiently. low, the vicinity was accepted without automatic fire' detection.and/or suppression.

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When the reouired systems identified earlier did not have sufficient redundancy and separation to satisfy either of the above criteria (1 or 2), alternate systems and/or power sources were considered.

If an alternate system or power source was relied upon to perform the shutdown function, then that system was reviewed to the above separation criteria. The Alternate Cooling Method (ACM)

System was considered to be an acceptable alternate power source, but was only considered when the normal power source could not provide the required separation.

Structures i

During field inspections, a general review of structures was performe'd. The main structure considered to be essential was the f

PCRV.

Due to the massive amount of concrete in the PCRV and its Support Ring, it was considered that no fire would jeopardize its capability to remain structurally sound.

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-Additionally, a's-the required systems were field inspected, an observation was made of surrounding structures.' A determination was r

imade whether or not it "was feasible that any structure posed a I

' serious threat of falling and damaging required. shutdown /cooldowii j

equipment during a: fire.. The amount of combustibles, the.o'penness of the area, and.the size of the nearby structure were. factored into_the-determination.

It was concluded 'that no modifications were necessary

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Attachment to P-84142 Page 9 to any structures because of a possible threat to shutdown /cooldown equipment during a fire.

Conclusions Based upon the results of the Fire Protection Review, it was concluded that no single fire would prevent FSV from achieving a safe, stable shutdown /cooldown condition and the health and safety of the public would be protected.

The required systems identified (listed previously in this summary)didnot in themselves satisfy the separation criteria.

However, when alternate systems were considered, it could be shown that sufficient redundancy and separation exists at FSV to reach the

' conclusion stated' above.

The two most notable alternate systems considered were:

1) the Firewater System which can supply cooling-water to the liner cooling tubes independent of both the Reactor Plant Cooling Water Pumps and the Service Water System; and 2) the ACM System which is an on-site, alternate power source which can power many of the required system components.

Additionally, certain deviations from the PSC-established Fire Protection Review criteria still existed after consideration of the alternate systems, but were determined to be justified for each specific case. One example is the fact that automatic fire' detection

p Attachm:nt to P-84142 Page 10 and suppression do not exist throughout the Reactor Building.

However, upon review of combustibles near the required equipment, it was determined that additional automatic detection and suppression were not warranted.

It was further determined that if such area wide suppression systems were installed and became activated a safety hazard could exist because the suppression system would create an environment for which shutdown /cooldown equipment is not qualified and could impede access by operating personnel.

Another deviation example deals with mechanical components (e.g. manual valves) which are required for depressurization of primary coolant.

In some cases, no alternate component was considered necessary because the normal component was not needed for two hours.

It was concluded that a nearby fire could be extinguished and manual actuation of the component within two hours would be feasible.

This concl.usion was based upon a review of the surrounding combustibles 7.nd the openness of the surrounding building.

Application of Section III.G of Appendix R to FSV lead to PSC's conclusion that the health and safety of the public will be protected regardless of any single fire at FSV. That conclusion agrees with earlier conclusions made when PSC designed its ACM System to provide power to required shutdown components in the event of a fire in the Control Room, Auxiliary Electric Room, 480 Volt Switchgear Room or congested cables along the

'J' 'or 'G' wall. At that time it was determined

-at these were the only areas where a fire could prevent

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Attachment to P-84142 Page 11 shutdown /cooldown of the plant.

It should be noted that the Fire Protection Review did not rely solely on the ACM System satisfying the criteria of Section III.G.3 of Appendix R.

Rather, the ACM

. System was considered as one of the alternate systems which could be considered to satisfy the established separation criteria.

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