ML18018B424

Forwards Detailed Description of Associated Circuits for Safe Shutdown After Fire for Use in Preparing Safe Shutdown Analysis

ML18018B424
Person / Time
Site:	Harris
Issue date:	10/18/1983
From:	Knighton G Office of Nuclear Reactor Regulation
To:	Utley E CAROLINA POWER & LIGHT CO.
References
NUDOCS 8311010471
Download: ML18018B424 (16)

Text

Docket Nos.:

50-400 and 50-401 i

Mr. E.

E. Utley Executive Vice President Power Supply and Engineering and Construction Carolina Power and Light Company Post Office Box 1551 Raliegh, North Carolina 27602

Dear Mr. Utley:

DISTR I BUT~

Document:

n'trol 50-400/401 NRC PDR QQT $ 8 ]983 L PDR NSIC H

PRC System LB83 Reading JLee BBuckley JHolonich

Attorney, OELD

Jordan, IE Taylor, IE GWKnighton TMNovak ACRS(16)

Subject:

Additional Guidance to Clarify Associated Circuits for Safe Shutdown (Shearon Harris)

On September 26 and 27, 1983, the NRC staff met with representatives from Carolina Power and Light Company to discuss fire protection at the Shearon Harris Plant.

During this meeting the staff agreed to forward to CP8L guidance on the subject of associated circuits for safe shutdown for a

nuclear power plant after a fire.

Enclosed is a detailed description of associated circuits which should be useful in preparing your safe shutdown analysis.

If you should require any additional assistance, please contact the Shearon Harris Project Manager, Mr. B. C. Buckley.

Sincerely,

Enclosure:

As stated cc:

See next page Original signetl by:

George Vl. Knighton George W. Knighton, Chief Licensing Branch No.

3 Division of Licensing D

~

0L J

10

/yt BC uck ey 3

10/I 7/83 ton 0//1 /83 83ijoi047i 83ioia PDR ADOCK 05000400 PDR'

~

~

r I;

ft N

P g

I

~ Il P

4

~

~

~

~

Shearon Harris,.

Nr.

E.

E. Utley Executive Vice President Power Supply and Engineering and Construction Carolina Power 8 Light Company Post Office Box 1551

Raleigh, North Carolina 27602 cc:

George F. Trowbridge,

Esq, Shaw, Pittman, Potts 5

Trowbridge 1800 f1

Street, NW Washington, D.

C.

20036 Richard E. Jones, Esq.

Associate General Consel Carolina Power 5 Light Company 411 Fayetteville Street Hall

Raleigh, North Carolina 27602 N. David Gordon, Esq.

Associate Attorney General State of North Carolina Post Office Box 629

Raleigh, North Carolina 27602 Thomas S.

Eevin, Esq.

115 M. tiorgan Street

Raleigh, North Carolina 27602 Nr. George Maxwell Resident Inspector/Harris NPS c/o U.S. Nuclear Regulatory Commission Route 1, Box 315B New Hill, North Carolina 27562 Charles D. Barham, Jr.,

Esq.

Vice President 5 Senior Counsel Carolina Power 8 Light Company Post Office Box 1551

Raleigh, North Carolina 27602 Nr. John Runkle, Executive Coordinator Conservation Council of North Carolina 307 Granville Road Chapel Hill, North Carolina 27514 Hr. Mells Eddleman 718-A Iredell Street Durham, North Carolina 27705 Hr. George Jackson, Secretary Environmental Law Project School of Law, 064-A University of North Carolina Chapel Hill, North Carolina 27514 Dr. Ph~j)is Lotchin Chapel Hill, North Carolina 27514 Mr. Travis Payne, Esq.

723 M. Johnson Street Post Office Box 12643

Raleigh, North Carolina 27605 Hr. Daniel F.

Read, President CHANGE Post Office Box 524 Chapel Hill, North Carolina 27514 Bradley M. Jones, Esq.

U.S. Nuclear Regulatory Commission Region II 101 tlarietta Street Atlanta, Georgia 30303 Richard D. Wilson, M. D, 725, Hunter Street Apex, North Carolina 27502 Regional Adminstrator - Region II U.S. Nuclear Regulatory Commission 101 Marietta Street Suite 3100 Atlanta, Georgia 30303 Karen E. Long, Esq.

Staff Attorney Public Staff -

NCUC Post Office Box 991

Raleigh, North Carolina 27602

Shearon Harris Dr. Linda Little Governor's Waste Nanagement Board 513 Albemarle Building 325 North Salisbury Street

Raleigh, North Carolina 27611

Ei<CLOSURE'SSOCIATED CIRCUIT GUIDANCE I;

IFTRODUU'IN-The,ollowing discusses the requirements for protec ing redundant and/or alternative equip;..ent needed for safe shutdown in the event of a fire.

The

~

~

require@ants of App ndix R address ho shutdown equipment which must be free of fire dar~ge.

The fo11owingrJ'.quirements also apply to cold shutdown equipaent M th licensee elects to de ons ryte that th

..equi>~en.is to be

,ree of. fire-datrage.

Appendix R does allow. repairable Cadge to cold shutdown

~

~

eauio-nt.

~

~

~ ~

Using the requirements of Sections III.G and III.L of Appendix R, the capa-bil'sty.o achieve hot shutdown must exist given a fire 4n any area of the plant in conjunction with a loss"of of.si e power for 72.hours.

Section III.G of App ndix R provides four methods for ensuring that the hot shutdown capa>>

bi>ity is protec ed from ires.

The firs" Awe options as defined in Sec ion III.G.2 provides methods for protection from fires of equipment needed for o

hot shut8own:

Redundant systems including cables.

equipment, and associated circuits ray be separa ed by a Dree-hour fire rated barrier; or,

~

e

\\

2.

Redundant sys.ms.including

cables, equipment and associa.

d circuits may be separated by a horizontal distance of more than 20 e t with no inter-vening co&ustibles.

In addition, ire detection and an automatic fire svppr ssion system are required; or, 3.

Redundant systems including cables, equipment and associated circuits may be enclosed by a one-hour fire ra ed barrier.

In addition,.ire detectors ard an au omatic fire suppression system are required

The las option as defined by Sec ion III.G.3 provides, a~ alter.native-shutdown capability to the redundant trains daraged by a fire.

4.

A'lternative shu-down equipment must be independeni of the cables, equip-men. an."'ssociated ci rcui is of the redundant systems damaged by ihe ire.

3Z.Associated Circui is of Corcern The followina discussion provid s A) a definition of associated circuits or Appendix R consideration, 8) ihe guidelines for proiec.ing the safe'shu.down'apability

,rom the ire-induced failures of associated circuits and C) the in-formation required by the staff to review associated circuits. I's important to no ie t.".at our interest is only with those circuit (cables) whose.ire-induced failure could affec. shutdown.

Guidelines or protect'ng

.he safe shutdown capability from the fire-induced failures of associated circuits are provided.

Thes'e guidelines do not limit the alternatives available to the licensee for protecting ihe shutdown capability.

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

A."'ur concern is that circuits within the fire area will receive,ire damage

~hich can affect shutdown capability and thereby prevent post-fire safe shutdown.

Associated Circuits o

Concern are defined as'hose cables (safety rela.ed, non-sa ety related, Class IE, and non-Class 1E) that:

The defini. on or associa ed circu-'

is noi exactly the same as the definition presented in I:.=:--%4-1977.

Have a physica1 separation less than that required by Section 7EE.G.2 of Appendix R,.and; 2.

Wave. one of the following:

a common power source with the shutdown equipment

{redundant or alternative) and the power source is not electrically protected from the cii cuit of concern by coordinated

breakers, fuses, or simi1ar devic s

(see diagram 2a), or b

a connec ion.o circui.s o

equipment ~hose spurious operation wou$d adversely affect.he shutdown capabili y (e.g.,

RHR/RCS isolation valves, ADS valves,

PORYs, steam generator atmospheri" dump valves, nstrumen,ation, st am bypass, e.c.)

(se diagram 2b), or c.

a cordon enclosure;(e.g.,

rac way, panel, junc ion) with the shutdown 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 eamon enclosure,

{see diagram 2c).

EXhIII'LES OF hSSOClhTED ClfICD1TS OF COIICEIIII s

~

1 I=me. heah I

I l

Flyer P ftQA f

I is O

ag f I

0- 605 Vhlsrpe I'un P

~Pampa~ tat/sert.'P~W QpCr~Yierpf Ccsu.M, 0.ffep sado m Qrpttilapgl 6'ucc,oc ~me The area barriers shown above meet the appropriate suh-paragraphs (a-f) of section Ill.6-2 of Appendix II.

Diagram 2h Diagram 20 Diagram 2C

B.

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

The shutdown capability may be protected from the adverse effect of damage to associated circuits of concern by the following methods:

l.

Provide protec ion between the associated circuits of concern and the shutdown circuits as per Section iLI;G.2 of Appendix R, or 2.

a.

FFor a common power source case of associa ed circuit:

Provide load fuse/breaker (interrup.ing devices) to feeder fuse/breaker coordination to prevent loss of the redundant or alternative shutdown power source.

To ensure that the following coordination criteria are met the fol"lowing should apply:

(1)

The associated circuit of concern in,errupting devices

'breakers or uses) time-overcurrent trip characteristic for all circuits faults should cause the interrup ing device to in errupt the fault current prior to initiation of a trip of any upstream interrupting device which will

'ause a loss of the common power. source, (2)

The power source shall supply the necessary faul. current for suf,icient time to ensure the proper coordination without loss of function of the shutdown loads.

~

The acceptabiTity of a par icular interrupting device is considered demons rated f.

the ollowing criteria are ".at:

(i).The intarrup.ing device design shall be factory tos.ad to verify overcurrent protection as designed in accordance with the applicable UL, ANSI, or NB% standards.

For low and m dium voltage switchgear (480 Y and above) circuit breaker/protective relay periodic.es.ing shall demonstrate that 2a overall coordination scheme remains within the limits specified in the design crit ria.

This tasting may be performed as a series of overlapping tesz.

(lii) tholded case circuit breakers shall periodically be manually exercised and inspected to insure ease of operation.

On a rotatirrg refueling outage basis a sample of these breakers shall be 'tes.ad to detarrAne that breaker drift is wi hin that allowed by the design criteria.

Breakers should be tested iver accordance with an accepted QC tes.ing methodology such as NIL ~i 10 5 O.

(iv)

Fuses when used as interrupting devices do not require

\\

perl odl c esting.

Administrative controls must insure that replacement uses with ratings other than those selected for proper coordination are no-accidentally used.

b.

For circuits of equip-...an and/or co~onents whose spurious ope. a.ion would a ect the capabili.y to sa ely shutdown:

~

~

v.6 (1) provide a means to iso'fat the equipment and/or components frcm the fire area prior to the fire (i.e.,

remove power cables, open circuit breakers);

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

Potential isolation devices include breakers, fuses, ampli--

fiers, control switches,'current XrrS, fiber optic couplers, relays a,id transducers; or (3) provide a'e ns

.o detect spurious operations and hen proce-dures to defeat the maloperation of equipment (i.e., closure of the block valve if PORV spuriously opera. es, opening of the breakers to remove spurious operation of safe.y injection);

c.

For cormon erclosure cases of associated circuits:

(1) provide appropriate measures to prevent propagation of the ire; and (2) provide,elec.rical protec.ion (i.e., breakers, fuses or similar devices)

C.

IHFQPMATIOH REOUIRED The following information is required to demonstrate that associated circuits will not prevent operation or cause maloperation of the shutdown method:

a.

Oescribe the methodology used to assess the potential of associated citcuit adversely affecting the shutdown capability.

The description of the methodology should include the methods used to identify the circuits which share a coction power supply or a

common 'enclosure with the 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 circuiys of concern due to their location in the fire area.

b.

Show that ire-induced failures (hat shorts, open circuits or shorts to ground) of each of the associated circuit:. o concern will'ot prevent operation o.

cause maloperation of the shutdown method.

Z.

The residual heat removal system is generall I

e era y a ow pressure sys.em that inter, aces with the. high pressure primary coolant sys em "o

preclude a

LOCA through this inter ace, we require compliance with the recommendations of Branch Technical Posi ion RSB 5-1 Thus he interface most likely consists of two redundant and independent mo or in ependent motor operated valves.

These two motor operated valves and their assoc<5ted cables may be subject to a single fire hazard.

It is our concern ha this single fire could cause the two valves to open resulting in a fire initiated LOCA through the high-Iow pressure system in inkier ace.

To assure

.hat this inter,ace and other high-Iow pressure interfaces are adequately protected from the ef,ec.s o

a of a single

ire, we require the following in orma ion:

a.

Identify each high-low pressure inter.ace that uses redundant elec.ric Ily controlled devices (such as two series motor opera.ed valves) to isolate or prec!ude ruotura cf any -"r'.,mar ol

...........----- ~; "*

~

~

~

~

~ ~

~

~ ~

.e b.

For each set ov redundant valves identzfsed sn a.,

vers y the redundant cabling (power and control) have adequate physical separation as required by Section III.G.Z of App ndix P..

C c

For each case where adequate sep"ration is nct provide:,

s.".o:; th=-t fire induced fai1ures (hot short, open circuits or shor. to ground) of the cables wi11 not cause naloperat on and r suit in a LOCA.

~

y 4

~