ML20052F156

Forwards Request for Addl Re Design Description of Mod Required to Meet Section III.B.3 of App R to 10CFR50.Info Must Be Received within 60 Days of Receipt of Ltr

ML20052F156
Person / Time
Site:	Yankee Rowe
Issue date:	04/28/1982
From:	Crutchfield D Office of Nuclear Reactor Regulation
To:	Kay J YANKEE ATOMIC ELECTRIC CO.
References
LSO5-82-04-085, LSO5-82-4-85, NUDOCS 8205120179
Download: ML20052F156 (29)

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'T Docket No. 50-29 N'@

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a RECElvgo Mr. James A. Kay

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Senior Engfeeer-Licensing

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Yankee Atomic Electric Company 6

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SUBJECT:

FIRE PROTECTION RULE - 16 CFR 50.48(c)(5) - ALTERNATIVE SAFE SHUTDOWN - SECTION III.G.3 0F APPENDIX R TO 10 CFR 50 RE:

Yankee Nuclear Power Station The Fire Protection Rule (10 CFR 50.48 and Appendix R to 10 CFR 50) became effective on February 17, 1981.

Paragraph 50.48(c)(5) required submittal of design descriptions of modifications needed to satisfy Section III.G.3 of Appendix R to 10 CFR 50 by March 19, 1981.

By letters dated March 19, 1981 and June 15, 1981, you submitted the design description of modifications required to meet Section III.G.3 of Appendix R to 10 CFR 50 for the Yankee Nuclear Power Station. We have reviewed your submittal and find that additional clarification of the infomation you sub-mitted is necessary for us to complete our review. The infomation required was originally requested from you by letter dated February 20, 1981. to this letter indicates the information we need. Please provide a complete response to the items indicated in the Enclosure within 60 days of l

receipt of this letter.

l provides a rewording of the request for information included with l

generic letter 81-12. This rewording is the result of meetings with repre-l sentative licensees who felt that clarification of the request would help expedite responses.

It does not include any new requests and, therefore, will i

not adversely affect licensees' ability to respond to generic letter 81-12.

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I Mr. James A Kay April 28,1982 j

i provides information regarding our criteria for evaluating i

exemption requests from the requirements of Section III.G.2 of Appendix R.

The reporting and/or recordkeeping requirenents contained in this letter affect fewer than ten respondents; therefore, OMB clearance is not required under P.L.96-511.

Sincerely, i

Original signed by l

Dennis M. Crutchfield, Chief Operating Reactors Branch #5 Division of Licensing

Enclosures:

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Mr. James A. Kay April 28,.1982 i-

• --.:cc Mr. James E. Tribble, President Yankee Atomic Electric Company 25 Research Drive Westborough, Massachusetts 01581 Chairman Board of Selectmen Town of Rowe

'1?' Rowe, Massachusetts 01'367

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1-Energy Facilities Siting Council 14th Floor One Ashburton Place Bosto.n, Mpssachusetts 02108 U. S.l Environmental Protection Agency Region I Office ATTN:

Regional Radiation Representative JFK Federal Building Boston, Massachusetts 02203 Residentinspector

. Yankee Rowe Nuclear Power Station c/o U.S. NRC Post Office Box 28 Monroe Bridge," Massachusetts 01350 Ronald C. Haynes, Regional Administrator Nuclear Regulatory Commission, Region I 631 Park Avenue King of Pr.ussia, Pennsylvania 19406 I

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ENCLOSURE 1

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YANKEE NUCLEAR POWER STATION ALTERNATIVE SAFE SHUTDOWN SYSTEM

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STAFF COMMENTS AND QUESTIONS

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1.

In response to a staff question regarding a fire in the Alternative Safe Shutdown System (ASSS) area, the licensee, Yankee Atomic Electric Company (YAEC), committed to design the system to prevent problems due to a fire.

In this regard, show that in the event of a fire in the ASSS area causing a hot short in the transfer switches located there, hot and cold shutdown can be effected. Alternatively, you should pro-vide a design which deals with this contingency. Also show that in the event of'a fire in the ASSS area (without resultast hot shorts in 1

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transfer switches) safe shutdown can be effected.

2.

Reference 4 discussed the use of a charging pump to control primary system pressure in the event the pressurizer heaters are lost. We request that.you confirm that procedures will be available before the ASSS ik made operational which provide for the maintenance of primary system pressure during hot shutdown in the event the pressurizer heaters become inoperable because of a fire which causes a loss of equipment in the fire areas under consideration, i.e., turbine building, control room, switchgear room (hereinafter to be designated as TB) and-ASSS area.

3.

We request that you commit to provide procedures for safe shutdown in the event of a fire in either the TB area or the ASSS area. You should also provide summaries of these procedures for staff review at this time.

The staff will review these summaries to ascertain whether safe shutdodn' can be accomplished with a total of three shift crew members and with the equipment outlined in your previous submittals.

4 Your response regarding single failures (Reference 2, Item C) requires further clarification. "The staff is' concerned that, in the design of new installations to provide safe shutdown in the event of a fire, which are also to be useo for other safe shutdown contingencies, the single

' failure criterion for safety systems will be abrogated. Therefore, you should provide assurance that the ASSS design will not permit a single failure to cause loss of redundant safety systems; e.g., control circuits for both RHR systems should not pass through one transfer switch, thus allo. wing loss of redundant safety systems by a single failure. Such a design does not comply with the criteria contained in Reference-6.

5.

Reference 2 reported three high-low pressure interfaces which use redundant electrically controlled devices to isolate the primary coolant bour.dary:

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the shutdown cooling system; b.

the main coolant drain and sampling system; and c.

the pressurizer power operated relief valves.

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You further stated that the shutdown cooling system (SCS) contained two high-low pressure interfaces which employed redundant. electrically-controlled motor operated valves in each of the two interfaces; two in' the suction, and in the discharge of the SCS to the primary system. You committed to modify the existing arrangement for these valves since it-appeared that all were inclose proximity and could be damaged in the event of a fire in the switchgear room; you also stated that the other systems required no modifications.

We request that you review the three interfaces noted above with regard ;.

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. to a possible fire in the Auxiliary Safe Shutdown System area in order to

. assure us that these interfaces are safe in the event of such a fire or commit to provide suitable modification to protect these interfaces.

6.

Describe how communications will be affected between the three operators e

conducting safe shutdown.

I 7.

Reference 2, Table 2 provided a list of instrumentation required for safe shutdown. With regard to this list, we have the following comments.

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a.

The list notes some instrument locations as " containment." Show how

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these, as well as all the other instruments necessary for safe shutdown, are accessible to the operators conducting safe shutdown operations a'ft'er a fire in the TB or ASSS.

b.

The staff interpretation of instrumentation required for safe shutd.wn includes the following for PWR's:

.i.

pressurizer pressure and level; ii.

reactor coolant hot leg temperature and either cold leg temperature or TAVG:

i t'i. steam generator pressure and level (wide range);

iv, source range flux monitor; v.

actual flow measurements for all pumps used; and

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level indication for all tanks used.

Your list differs in that you specify the use of either incore thermocouples or loop thermocouples, and you do not include either flow measurements or the measurement of tank levels which provide fluid for the systems involved.

We request that you either commit to provide the omitted instrumentation required in Items ii, v and vi above or provide acceptable alternatives to permit suitable operational surveillance of the systems involved in proceeding to hot and then to cold shutdown after a fire in the TB or ASSS area.

In this, you should follow the guidance of Appendix R, to 10 CFR 50, Section III.L.2.

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8.

Discuss the ' steps to be taken to assure satisfactory control of plant

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reactivity as it proceeds to hot shutdown and then to cold shutdown.

9.

Provide design information to show that the isolation devices intended for use in the ASSS area are in compliance with the criteria outlined in of this letter or provide suitable alternate means of isolation.

10.. It is anticipated that a control room fire could cause spurious signals resulting in undesirable operation of some of the equipment for safe shutdown which will be controlled in the ASSS area.

Show that this will'not prevent.

safe shutdown from the ASSS area.

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Please ensure that you have provided responses to all items required by Reference 6, or Enclosure 2 to this letter,.

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R'eferences 1,

P.' Telecon, UStiRC with (AEC, dated January 26, 1982..

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' ~ - 27 Letter, J. A. Kay (YAEC) to Darrell G. Eisenhut (USNRC), dated June 15, 1981.

SubjectL " Additional Infontation on Alternative Safe Shutdown System

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Proposal."

3.

Letter, L. H. Heider (YAEC) to Harold Denton (USNRC),' dated March 19, 1981,

Subject:

" Compliance with Appendix R to 10 CFR 50."

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Telecon, BNL, YAEC, USNRC, dated November 23, 1981,

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Telecon, 'BNL, YAEC, USNRC, dated November.20, 1981.

6.

Ldtter to all Power Reactor Licensees with Plants Licensed'. Prior to l

January 1,1979, from U.

S'. Nuclear Regulatory Comission dated February 20, 1981,

Subject:

" Fire Protection Rule (45 FR 76602, Novenber 19. 1980)

Ge'neric Lett'er 81-12."

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CLAPIFICATI0tl 0F GEtiERIC LETTER On February 20, 1981, generic letter 81-12 was forwarded to all reactor licensees with plants licensed prior to January 1, 1979. The letter' restated the require-

" ment of Section 50.48 to 10 CFR Part 50 that each licensee would be required e

' to reassess areas of the. plant where cables or equipment including associated non-safety circuits of, redundant trains of systems necessary to achieve and

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u nNknta. n hot shutdown conditions are located to determine whether the require i

ments of Section III.G.2 of Appendix R to 10 CFR 50 were sa. tis'fied. Additionally,

.s m-Enclosure } and Encl,osure 2 of the-generic letter requested additional information concerning those areas of the plant requiring alternative shutdown capability. Section 8 of Enclosure 1 request'ed information for the systems, equipment and procedure's of alternative shutdown capability and Enclosure'2~

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defined associ,ated circuits and requested information concerning associated

-- circuits for those areas requiring alternative shutdown.

In our r.eview of licensee submittals and meetings with licensees, it has become-apparent that the request for information should be clarified since.a lack-of clarity could result in the submission of either insufficient or e,xcessive 1

information. Thus, the staff'has rewritten Ssetion 8 of Enclosure 1 and :

~ of the February,20,1981, generic letter. Additionally, further.

clarification of the definition of associated circuits has been provided to aid in the reassessments to determine compliance with the requirements of I

Sections III.G.2 and III.G.3 of Appendix R.

In developing this= rewrite we have i

i The attached conside' red the comient of the Nuclear Utility Fire Protection Group.

rewrite of the Enclosures contains no new requirements but merely attempts to clarify the request for additional information.

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Lide~n' ees who have not responded to the February 20, 1981 generic letter, s

may choose to respond to the enclosed request for information. Since the 1

enclosed request for information is not new, but merely clarification of our previous letter, responding to it should not delay any submittals. in

' progress that hre based upon February 20, 1981 letter. Licensees whose

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response.to the February 20, 1981 letter, has been found incomplete resulting in staff identifications of a major unresolved item (14e., associated circuits),

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i may choose to respond to pertinent sections of the enclosed request for infor-i mation in order to close open items (i.e., open item for. assoc'iated circuits, use rewrite of Enclosure 2).

If additiona.1 clarification is needed, please contact the staff Project Manager for your plant.

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J REk'P.ITE OF SECTION 8 REQUEST FOR ADDITIONAL INFORKATI0fj

.The. following is. a rewrite of the staff's request for additional inforination

,concerning design modification to meet the requ'irements of Section III.G.3 of Appendix P..

The following contains no new requests but is.merely a rewording of

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Section 8 of Enclosure 1 vf the February 20,'1981 generic letter.

-1 v Ide'ntify those areas of the plant that will not meet the requirements of;...

Section III.G.2 of Appendix R and', thus alternative shutdown will be provide'dx

, or an exemption from the requirements of Section III.G.2 of Appendix R will' be provided. Additionally provide a statecent that all other areas of, the plant are or will be in compliance with Section III.G.2 of Appendix R.

For each of those. fire areas of the plant requiring an' alternative shu.tdown

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systen(s,) provide a complete set of responses to the following requests for

- each f. ire area:

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List the system (s) or portions thereof used to provide the shutdown a.

capability with the loss of offsite power.

b.

For those systems identified in '.'la" for which alternative or dedicated shutdown capability must be provided, list the equipment and components of the normal shutdown. system in the fire area and identiff the functions

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o'f 'the circuits of the normal shutdown system in the fire area (power to what equipment, control of what components and instrumentation).

Describe the system (s) or portions thereof used to provide the alternative shutdown capability for th~e fire area and provide a table tbat lists the equipment and components of the alternative shutdown system for the~ fire area.

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For each alternative system identify the function of the new circuits being provided.

Identify the location (fire zone) of the alternative shutdown equipment and/or circuits that bypass the fire area and verify that the alternative shutdown equipment and/or circuits are separated from the fire area'in accordance with Section III.G.2.

Provide drawings of the alternative shutdown system (s) which highlight 'any c.

connections to the normal shistdown systems (P& ids for pip 1ng ana components, elementary wiring diagrams of electrical cabling). Show the electrical iocation of all breakers for power cables, and isolation devices for control and instrumentation circuits for the alternative shutdown systems

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for that fire area.

d.

Verify that changes 'to safety systems will not degrade safety systems; (e.g.", new isolation switches and control switches should meet des.ign criteria and standards in the FSAR for electrical equipment in the-i;ystem that the switch it to be installed; cabinets that the switches are to be mounted in should also meet the same criteria (FSAR) as other safety related cabinets and panels; to avoid inadvertent isolation from the co.ntrol room, the isolation switches should be keylocked or alarmed in the control room if in the'" local" or " isolated" position; periodic checks should be made to verify that the switch is in the proper position for normal operation; and a single transfer switch or other new device should 4

not be a source of a failure which causes loss of reaunaant safety

systems).

c.'

Verify that licensee procedures have been or will, be develo' ed which describe the p

tasks to be perfomed to effect the shutdown _ method.

Provide a summary

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of these procedures outlining operator actions.

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Verify that the manpower required to perform the shutdown functions using the procedures of e5 as well as to provide fire brigade members to fight the' fire is available as required by the fire brigade technical spect-

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fications.

9 Provide a commitment to perform adequate scceptance tests of the alter-

' 7 na tive shutdown capability.

These tests should verify that:

equipmint'

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operates from the local control station when the transfer or isolation switch is placed in the " local" position and that the equipment cannot be o,perated from the control room; and that equipment operates from'the l

control room but cannot be operated at the local control station when the transfer isolation switch is in the " remote" position.

h.

Provide Technical Specifications of the surveillance requirements and limiting conditions for operation for that equipment not already

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covered by existing Technical Specifications.

For example, if new isolation and control switches are added to a shutdown system, the existing Technical Specification surveillance requirements should

' 'be supplemented to verify system / equipment functions from the alternate shutdown station at testing intervals consistent with the guidelines of Regulatory Guide 1.22 and IEEE 338.

Credit may be taken for other existing tests using group overlap test concepts.

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i For new equipment comprising the alternative shutdown capability, verify that the systems available are adequate to perform the necessary shut-down function.

The fuhetions required should be based on previous analyses, if possible (e.g., in the FSAR), such as a loss of normal ac power or shutdown on Group 1 isola, tion (BWR).

The equipment required'.

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,for the alternative capability should be the same or equivalent to that relied on in the above analysis.

j Verffy. that repair procedures for cold shutdown systems are developed Iand material for repairs is maintained on site.

Provide a summary of these procedures and ailist of the material needed for repairs.

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SAFE SHUTDOWN CAPABILITY

.The following discusses.the, requirements for. protecting redundant and/or The ~

alternative equipment needed for safe shutdown in the event of a fire.

'reatii'rements of Appendix R address hot shutdown equipment which must b The followlng reqpirements also apply to cold.s,hutdown fr.ee of fire damage.

equipment if tha licensee elects to demonstrate that the.equipgent.is to be, free of. f. ire. damage.

Append 6 R does allow re'pairable damage to cold shutdown coufement.

Using the requirements of Stctions III.G and III.L of Appendix R, the ca'pa -

bility't6 achieve hot shutdown must exist gi'ven a fire in any area of the i

plant in conjunction with a loss.of offsite power for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.

Section III.G of. Appendix R provides four methods for ensuring that th'e hot shutdown capa-bility is protected from fires. The first three options as defined in Ssction

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III.G.2 provides methods for protection from fires of equipment needed for hot shutdown:

'1.

Redundant systems including cables, equipment, and associated circuits' may be separated'by a three-hour fire r'ated barrier; or, f

Redunpant systems.tncluding cables, equipment and associated circuits may 2.

be separated by a horizontal distance of more than 20 feet with no inter-l vening, combustibles.

In addition, fire detection and an automatic fire suppression system are required; or, 3.' Redundant sjistems including cables, equipment and associated circuits may

-t by enclosed by a one-hour fire rated barrier.

In addition, fire detectors and an-autom tic fire suppression system are required.

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The last' option as defined by Section III.G.3 provides an alternative shutdown

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c5pability to the redundant trains damaged by a fire.

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Alternative shutdown equipment must be independent of' the cables, equip-ment and associated circuits of the redundant systems damaged by the fire.

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' 7-Associated Circuits of Concern 1

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The following discussion provides A) a definition of associated circuits for Appendix R consideration, B) the guidelines for protecting the safe' shutdown capability from the fire-induced failures of associated circuits and C) the in-formation required by the staff to review associated circuits.

The definition

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of associated circuits has not changed from the February 20, 1981 generic 1etter; but is merely clarified.

It is important to note that our interest is only with those circuit (cables) whose fire-induced failure could effect shutdown.

The guidelines for protecting the safe shutdown capability from the fire-iriduced failures of associated circuits are not requirements.

These guidelines should be used only as guidancs when needed. These guidelines do not limit the alter.

natives available to the licens2e for protecting the shutdown capability.

All proposed methods for protection of the shutdown capability from fire-induced' failures will be evaluated by the staff for acceptability..

A.

Our concern is that circuits within the fire area.will receive fire damage yhich can affect shutdown capability and thereby prevent post-fire safe

. shutdown. Associated Circuits

• of Concern are defined as those cables (safety N1ated, non-safety related, Class 1E, and non-Class 1E) that:

• The definition for associated circuits is not exactly the same I

as the definition presented in IEEE-384-1977.

i-1.

Have a-physical separation less than that required by Section III.G.2

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of Appendix R,.and; 2.

Have one of the following:

a common power source with the shutdown ' equipment (redundant or a.

alternative) and.the power source is not electrically protected

'from the circuit of concer,n by coordinated breakers, fuses, or similar devices (see diagram 2a), or

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,a connection to circuits of equipment whose spurious operation I

would adversely affect,the shutdown capability (e.g., RHR/RCS isolation valves, ADS valves, PORVs, steam generator atmospheric

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dump valves, instrumentation, steam bypass, etc.) (see diagram 2b), or a common enclosure (e.g., raceway, panel, junction) with the shutd wn c.

cables (redundant and alternative) and, (1) are not electrically protected by circuit breakers, fuses or simi-lar devices, or (2) will allow propagation of the fire into the common enclosure, (see diagram 2c).

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t EXAMPLES OF ASSOCIATED CIRCUITS OF CONCERN

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of section III.G-2 of Appendix R.

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.B..Jhe following guidelines are for protecting the shutdown capability from fire-induced failures of circuits (cables) in the fire area.

The guidance provided below for interrupting devices applies only to new devices installed to provide electrical isolation of associated circuits of concern, or as part of the alternative or dedicated shutdown system. The shutdown capability may be protected from the adverse effect of damage to associated circuits ~

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.of concern by the following methods:

1.

Provide pr'otection between the associated circuits of concern and ithe shutdown circuits as per Section III.G.2 of Appendix R, or For a connon power source case of associated circuit:

2.

a.

' Provide load fuse / breaker (interrupting devices) to feeder fuse / breaker coordination to prevent loss of the redundan't or -

Toensurethatthefollowinh alternative shutdown power source.

coordination criteria are met the 'fol-)owing should apply:

(1) The associated circuit of concern interrupting devices '

(breakers or fuses) time-overcurrent trip characteristic for all circuits faults should cause the interrupting I

device to interrupt the fault current prior.to initiation i

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of a trip of any upstream interrupting device which will cause a loss of the connon power source, t

,(2) The power source shall supply t'he necessary fault current for sufficient time to ensure the proper coordination without loss of function of the shutdown loads.

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The acceptability of a particular interrupting device is considered demonstrated if the following criteria are met:

(i)

The interrupting device design shall be' factory tested to verify overcurrent protection as designed in accordance with the applicable UL, ANSI, or NEl% standards.

(ii)

For low and medium voltage switchgear (480 V.and above) circuit breaker / protective relay periodic testing shall demonstrate that the overc11 coordination scheme' remains i

within the limits specified in the design criteria. This testing may be performed as a series of overlapping tests.

(jii) Molded case circuit breakers shall peridically be manually exercised and inspected to insure ease of operation.. On~

a rotating refueling outage basis a sample of these brea ers shall be tested to determine that breaker drift is within that allowed by the design criteria.

Breakersshould be tested in accordance with an accepted QC testing methodology such as MIL STD 10 5 D.

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Fuses when used as interrupting devices do not require

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periodic testing, due to their stability, lack of' drift, and high reliability.

Administrative controls must insure

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that replacement fuses with ratings other than those-selected for proper coordinating are not accidentally used.

b.

For circuits of equipment and/or components whose spurious operation would affect the capability 'to safely shutdown:

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s (1). provide a means to isolate the equipment and/or components from the fire area prior to the fire (i.e., remove power cables, open

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circuitbreakers);or (2) provide electrical isolation that prevents spurious operation.

Potential isolation devices include breakers, fuses, ampli-fiers, control switches, current XFRS, fiber optic couplers, relays and transducers; or (3) provide a means to detect spuntous operations and then proce-dures to defeat the maloperation of equipment (i.e., closure of the block valve if PORV spuriously operates, opening of the breakers to remove spurious operation of safety injection);

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For common enclosure cases of associated circuits:

c.

(1) provide appropriate measures to prevent propagation of the fire; and (2) provide electrical protection (i.e., breakers, fuses or similardevices)

C.

We recognize that there are different approaches which may be used to reach the same objective of determining the interaction of associated circuits with shutdown systems. One approach is to start with the fire area, identify what is in the fire area, and' determine the interaction between what is in the fire area and the shutdown systems which are outside the fire area. We have entitled this approach, "The Fire Area Approach." A second approach which we have named "The Systems Approach" would be to define the shutdown systems around a fire area and then determine

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those circuits that are located in the fire area that are associated i

with the shutdown system. We have prepared two sets of requests for information, one for each approach. The licensee may choose to respond to either set of requests depending on the approach selected by the licensee.

FIRE AREA APPROACH 1.

For each fire area where an alternative or dedicated shutdown method, in accordance with Section III.G.3 of Appendix R is provided, the fo) lowing information is required to demonstrate that associated i circuits will not prevent operation or cause maloperation of the alternative or dedicated shutdown method:

a.

Provide a table that lists all the power cables in the fire area that connect to tbn same power supply of the alternative or _

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dedicated shutdown method and the function of each power cable'-

listed (i.e., power for RHR pump).

b.

Provide a table that lists all the cables in the fire area that

were considered for possible spurious operation which would adversely affect shutdown and the function of each cable listed.

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c. ~ Provide a table that lists all the cables in the fire area that share a common enclosure with circuits of the alternative or dedicated shutdown systems and the function of each cable listed.

d.

Show that fire-induced failures (hot shorts, open circuits or shorts to ground) of each of the cables listed in a; b, and c will not prevent operation or cause maloperation of the alternative or dedicated shutdown method.

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e.

For each cable listed in a, b and c where new electrical isolation has been provided or modification to existir.g electrical isolation has been made, provide detailed electrical schematic drawings that show how each cable is isolated from the fire area.

SYSTEMS APPROACH 1.

For each area where an alternative or dedicated shutdown method, in accordance with Section III.G.3 of Appendix R is provided, the following information is required to demonstrate that associated I circuits will not prevent operation or cause maloperation of the alternative or dedicated shutdown method:

a., Describe the methodology used to assess the potential of associated circuit adversly affecting the alternative or dedicated' shutdown.

The description of the methodology should include the methods-used to identify the circuits which share a common power supply or a conmon enelosure with the alternative or dedicated shutdown system and the circuits whose spurious operation would affect shutdown. Additionally, the description should include the methods used to identify if these circuits are associated circuits of concern due to their location in the fire area.

b.

Provide a table that lists all associated circuits of concern located in the fire area.

c.

Show that fire-induced failures (hot shorts, open circuits or shorts to ground) of each of the cables listed in b will not prevent operation or cause maloperation of the alternatife or dedicated shutdown method.

e d.

For each cable listed in b where new electrical isolation has been

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provided, provide detailed electrical schematic drawings that

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show how each cable is isolated from the fire area.

Provide a location at the site or other offic'e_s where all the e.

tables and drawings generated by this metho' dolo'gy approach for the associated circuits review may be audited to verify the information provided above.

i HIGH-LOW PRESSURE INTERFACE For either approach chosen the following concern dealing with high-low.

pressure interface should be addressed.

2.

Th'e residual heat removal system is generally a low pressure system that interfaces with the high pressure primary coolant system. To, preclude a LOCA through this interface, we requi.re compliance with the recommendations of Branch Technical Position RSB 5-1.

Thus,-the

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interface most lik51y consists of two redundant and independent motor

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ope' rated valves. These two motor operated valves and their associdted-

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cables may be subject to a single f. ire hazard.

It is our concern that this single fire could cause the two valves to open resulting in a fire initiated LOCA through the high-low pressure systeri interface.

To assure that this interface and other high-low pressure interfaces are adequately protected from the effects. of a single fire, we require the following information:

a.

Identify each high-low pressure interface that uses redundant electrically controlled devices'(such as two series motor operated valves) to isolate or preclude rupture of any primary. coolant boundary.

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b.

For each set of redundant valves i'dentified in a., verify the -

redundant cabling (power and control) have adequate physical separation as required by Section III.G.2 of Appendix R.

c.

For each case where adequate sep ration is net provided, sho': that fire induced failures (hot 'short, open circuits or short to ground)'

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T of the cab 1'es will not cause maloperatioii and result in a LOCAr e

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tnLLusunt a CRITERIA FOR EVALUATIt1G J

EXEMPTIONS TO SECTI0f1 III G OF APPErlDIX R

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3 0F 10 CFR PART 50

. Paragraph 50.48 Fire Protection of 10 CFR Part 50 requires that all ndclear power plants licensed prior to January 1,1979 satisfy the requirements of Section III.G of Appendix R to 10 CFR Part 50.

It also requires that alternative fire protection configurations, previously approved by an SER be reexamined for compliance with the requirements of Section III.G.

Section III.G is related to fire protection features for ensuring that systems and associated circuits used to achieve and maintain safe shutdo'wn -are free of fire damage.

Fire prot 6ction configurations must either meet the specific require-

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"rdents of Section III.G or an alternative fire protection configuration '

must belustified by a f4e hazard analysis.

The general criteria for accepting an alternative fire protection configur-ations a're the following:,

The alternative assures that one train of equipment necessary to achieve hot shutdown from either the control room or emergency control stations is free of fire damage.

The alternative assures that fire damage to at least one train of equipment necessary to achieve cold shutdown is limited such that it can be repaired within a reasonable time (minor repairs with

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components stored on-site).

Fire retardant coatings are not used as fire barriers.

Modifications required to meet Section III.G would.not enhance fire protection safety above that provided by either existing or proposed alternatives.

Modifications required to meet Section III.G would be detrimental to overall facility safety.

Because of the broad spectrum of potential configurations for which exemptions may be requested, specific criteria that account for all of the parameters that are important to fire protection and consistent with safety requirements of all plant-unique configurations have not been devel.oped.

However, our evaluations of deviations from these require-ments in our previous reviews and in the request's for III.G execptions received to date have identified some recurring configurations for which specific criteria have been developed.

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4 2-Section III.G.2 accepts three methods of fire protection.

A passive

~ 3~-hour fire barrier should be used where possible.

Where a fixed barrier cannot be installed, an automatic suppression system in combination with

.a fire barrier or a separation distance free of combustibles is used if the configurations of systems to be protected and in-situ combustibles are such that there is reasonable assurance that the protected systems will survive.

If this latter condition is not met, alternative shutdown capa-bility is required and a fixed suppression system installed in the fire area of concern, if it contains a large concentration of cables.

It is

' ~* essential to' remember that these alternative requirements are not deemed.

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' to be equivalent.

However, they provide adequate protection for those configurations in which they are accepted.

When the fire pcotection features of each fire area are evaluated, the whole ' system of such features must be kept in perspective. The defense-in-depth principle of fire protection programs is aimed at achieving an adequate balance between the different features.

Strengthening any one can compensate in some measure for weaknesses, known or unknown in others.

The adequacy of fire protection for any particular plant safety system-or area is determined by analysis of the effects of postulated fire relative to maintaining the ability to safely shutdown the plant and minimize radio-active releases to the environment in the event of a fire. During thes,e evaluations it is necessary to consider the two-edged nature of fire protection features recognized in General Design Criterion 3 namely, fire

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protection should _be provided consistent with other safety consideratio,n,s.

An evaluation must be made for each fire area for which an exemption is requested.

During these evaluations, the staff considers the following parameters:

A.

Area-Description walls, floor, and ceiling construction

- ceiling height room volume ventilation congestion B.

Safe Shutdown Capability number of redundant systems in area whether or not system or equiment is required for hot shutdown type of equipment / cables involved repair time for cold shutdown equipant within this area separation between redundant components and in-situ concentration of combustibles alternative shutdown capability t

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...C.

Fire Hazard Analysis type and configuration of combustibles in area

~ quantity of combustibles ease of ignition and propagation heat release rate potential transient and installed combustibles suppression damage to equipment whether the area is continuously manned _

traffic through the area accessibility of the area D.

F. ire Protection Existing or Committed 3

fire detection systems 3-fire extinguishing systems ho,se station / extinguisher radiant heat shields, A specific description of the fire protection features of the configuration is requ~ifed to justify the compensating features of the alternative.

Low fire loading is not a sufficient basis for granting an exemption in area.s where there are cables.

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If necessary, a team of. experts, including a fire protection engineer, will. visit the site to determine the existing circumstances. This visual inspection is also considered in the review process.

The majority of the III.G-exemption requests received to date are being I,

denied because they lack specificity.

Licensees have not identified the extent of the exemption requested, have not provided a technical basis For the request and/or have not provided a specific description of the alternative. We expect to receive requests for exemption of the following nature:

I 1.

Fix'ed' fire barriers less than 3-hour rating.

Fire barrier without an automatic fire suppression system. '

2.

3.

Less than 20 feet separation of cables with fire propagation

.. retardants (e.g., coatings, blankets, covered trays) and an automatir suppression system.

For large open areas with few components to be protected and few in-situ 4.

combustibles, no automatic suppression system with separation as in Item 3 above.

5..No fixed suppression in the contr'o'1 to'om.

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No fixed' suppression in areas without a large concentration of cables for which alternative shutdown capability has been' provided.

Our fire research test program is conducting tests to. provide information that will be useful to determine the boundary of acceptable conditions for fire protection configurations which do not include a fire rated barrier.

Basedondehiationsrecentlyapproved,specificcriteriaforcertain

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recurring. configurations are as follows:

Fire Barrier Less than Three Hours This barrier is a wall, floor ceiling or an enclosure which separates one: fire area from another.

Exehptions may be granted for a lower rating (e.g., one hour or two hou's) r where the fire loading is no more than 1/2 of the barrier rating. The fire rating of the barrier shall~be no less than one hour.

Exemptions may be granted for a fixed barrier with a lower fix rating ~

supplemented by a water curtain, An Automatic Suppression System With Either One Hour Fire Barrier or-20-Foot Separation 7.

This barrier is an enclosure which separates those portions of one division which are within 20 feet of the redundant division.

The suppressant may be water or gas.

Exempt. ions may be granted for configurations of redundant systems which

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For example:

k.

Separation distances less than 20 feet may be deemed acceptable where:

1.

Fire propagation retardants (i.e., cable coatings, covered trays, conduits, or mineral wool blankets) assure that fire propagation through in-situ combustibles will not occur or will be delayed sufficiently to ensure adequate time for detection and suppression.

2.

Distance above a floor level exposure fire and below ceiling assures that redundant systems will not be simultaneously subject to an unacceptable temperature or heat flux.

B.

The ommission of an automatic suppression system may be deemed acceptable where:

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Distance above a floor level exposure fire and below ceiling assures I

that redundant systems will not be simultaneously subject to an unacceptable temperatu.re or heat flux.

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.2.-

The fire area is required to be manned continuously by the provisions

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in the Technical Specifications.

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