ML19259C077

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Describes Design Change to Provide control-grade Trip of Reactor on Generator/Turbine Trip &/Or Loss of Main Feedwater
ML19259C077
Person / Time
Site: Rancho Seco
Issue date: 05/30/1979
From: Oubre R
SACRAMENTO MUNICIPAL UTILITY DISTRICT
To: Garner R, Thatcher D
NRC COMMISSION (OCM), Office of Nuclear Reactor Regulation
References
NUDOCS 7906120326
Download: ML19259C077 (5)
v • d • e


Text

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Mr. Dan Carner rnOM:

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Rancho Scro Nuclear ceu. Srnrion U.S. ' Nuclear Regulat ory Consisfeion f~

REACTOR' TRJP SCIIEME r

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Dale 'Ihatch7r g,39,79 g;.~

DESCRIPT)ON:

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ThE purpose of this design change tw to provide a cont rol-grnde trip of the reactor on generator / turbine trip,and/or lons of rnain feedwater.

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The. attached drawing shows the proposed trip scherte.

All the p.co rnter/

M turbine trips vi]I energize the trip and lock onC 886 relay.

The 88f. retny contact will energize t.he reactor trip (RXT) relny.

The J ors cf feedvater is

> rnonitored by the low pressure switches (PSL31767 and PSI.317hM) s.nd opernte to energize the RIT relay through the target relay 30 YPT.

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Trippihg of the reactor is acconplished by tripping the CRU AC "A" nnd "B" I!

breakers throu8h the shunt trip devices on the breakers.

The =hunc trip coil is being supplied power from 72-A06. for breaker "A" and 77-R06 for brenker "B".

The. design requires that'the circuits from 72-A06 anA 72-804 both be in t h e-saree cabinet.. This.will require thne adequate separation of enbles nnd fnrcrnn!

g viring-tis maintained by physical. separation, copper brafd. f l aria are and ginns b

. tope over brsId and covered with heat shrfnk tubing.

The design doca not h

eIcetricmIly inter-ele the control-grade circuit with the Cinas IE RPS trip circuit..

5 The deadf[t crl'teria used are:-

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U M e tripivill be a control-grade trip not designed to neet single totiv.re criteria and will:; require power to trip.

2.

Trippjng of the reactor on lons of rsain feedunter ontf/or turbine generr. tor trip shall not degrade the RFS trip of the reactor.

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3.

The trip of the reactor will be accomplished independent of the ICS system.

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4.

The. trip. shill be accoop11shed using a 123VDC power supply.

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Separation of redundant channel cables sha13 be. mnintained on in the Initial j

plant deisign.

5 6.

De circuit shall be designed to allow testinp, of the circuit with the Plant in operation, 7.

If OCB-220, 230 and che ' field breaker are npen, a ' trip of the turbine g

shall not' trip the reactor.

8.

All electrien1 and mechanical protective trips of the tuchtne and/or generator shall initiate trip of the renetor, e,... _.

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The key switch;mnd. indicating. I f ght are located in the crmtrol renh-Wini ~

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the key suitelWis used to cut out renctor trip on Jonn of facdvater d st Eng plant. startup asd shutdown.

The indienting light in u*cd to en Q ap the U. ~'.l L -

trip scheme whed the key switch in cut out.

Con t rul room nnnunc'intor L

  • activated whenenre1r key swit.ch is in the ex-out. mit.ivm..

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REACTOR TRIP !SCEEME j

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. g - - RIT KEY SWITCH

-HPT CUT-OUT f

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CRD CRD ABN

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BREAKER 3REAKER j,.

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B CONTROL j'

' TRIP TRIP

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ddd - GENERATOR / TURBINE TRIP AND LOCK OUT RELAY.

eSL - FEF.D MA'IES PRESSURE SWITCllES - CONTALTSIMADE ON LOW PRESSURE t

RXT - REACTOR TRIP RELAY l

WPf - TAHCtY RELAY TOR REACTOR TRIP ON' LOSS' OF EEEDWATER

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EtY dulTCH - LOC.1TED IN CONTROL R0011 - ANNUNCIATES V11E5 KZY NOT IN 30A2GL POSITION.

(FPC CUT-OUT =! FEED FUMP TRIP CUT-0UT)

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-is IL - INDICAIING LICitr (USED TO MONITOR. TRIP CIRCUlT OP PSL BEFORE SWITCH i

IS Ptrr EM HOR!fAL POSITION).

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PROPOSED SURVdII.t.A?{CE PROCEDURE

'Ihis procedure is required on a monthly cycle while plant in on line.

L' hen the plant is shut down* then STP-827 vill be used to verity that the reactor trip scheme is operable. } The STP v113. be converted to an (EM (electrical maintenance) procedure to tneet this requirenent.

1 PROCEDURE:

DATE I!!IT I AI.

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Obtain permission from Operations to perf oru this SP

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2.

Verify that CRD system is nortnal (no alarms) and all breakexa and power supplies in service.

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3.

At panel R3PRCO2, jumper trip contacts 1 & 2 of RXT relay.

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4.

Remove jumper used in step 3.

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5.

Verify that CRD AC Breaker "A" was tripped.

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6.

Reset CRD AC Brunker "A".

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MUTE:

This requires that breaker be closed by nanus 1 controls at CRD AC Breaker "A" panel.

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P* peat step 2.

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8.

At'_ panel 113PRCO2 jumper trip contacts 12, & 13 of RIT relay.

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9.

Remove Jumper used in step 8.

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10.

I,' Verify that CRD AC Breaker "B" has tripped.

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11.,

Reset CRD Ad Breaker "B".

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NUTE:

This requires that breaker be closed by. cannel contrala at CRD AC Breaker "B" panel.

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Repeat step 2.

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13.,

Notify Operations that procedure is cornpleted.

  • Planned outage where unf e is down for a fixed period of tine.

Thim doe 9 not include inadvertent trips where planc is put right back Jn service.

Page 3 of 5

II.1.ECO::S UITH Dale Thatchar

.o Inittared C.nl Who Vas " Con tac ced Date H.

Young D.

Thatcher -

5/29/79 10:10 a.m.

P 1:eason for Call:

To clarify the following item:

13 Key by-p.saa switch to be used in' reactor trip scheme.-

2)

Surveillance procedura for the reactor trip sche.ne..

Resolution Reached:

1)

A Lef by p.sss ~awitch will be addgd to the feed water pressure avitch loop of the. react.or trip schece that will alarm in the control room when the switch La not in the normal poaltion.

2) to c.infuien or eltninate the operation of/the relay cut-out switches, che su r ve l II.in ce procedure will require that a jumper be used to trip ona (1) cun bre.sker at a time while the other CRD breaker rannina closed.

'this fu co be done while plant is operating.

When plant is shut down, then fg g g or a form of shall be perf ore.ed to verify the operation of citecuits.

w or c.he previous, testa (SP of SIP) will be performed at least every 30 One days.

Requ.: e :f.s.le:

Will tulC agree to the above?

l Date Respanae Requested:

tiy end of today.

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Page 4 of 5

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TELECONS U1711 Dale Thatcher W a Initisced C.sl Uho Ums contacced Date

L Dalo Ilutcher H. Young 5/29/79 12-41 p.m.

Besson for Call:

See pr.svious snamo

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Regalucion EcAched:

Concurred with previous c-ats.

Ifa vill have his hose call P. Cubre' and clarify the use of relay with cut-out sultches.

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Request Lade:

Mau Dare.% span =c Requested:

Nona required, cc 21 Brock V. Quh re ',

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