ML20039D550

Forwards Proposed Change to FSAR Concerning Resolution of Open Tech Spec Item Re End of Cycle Recirculation Pump Trip. Proposed Change Will Be Documented in Amend to FSAR

ML20039D550
Person / Time
Site:	LaSalle
Issue date:	12/29/1981
From:	Sargent C COMMONWEALTH EDISON CO.
To:	Schwencer A Office of Nuclear Reactor Regulation
References
NUDOCS 8201050191
Download: ML20039D550 (5)

Text

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'/ /

N Commonwealth Edison

) one First National Plaza. Chictgo, Illinois

( T 7 Address Reply to: Post Office Box 767 N ,/ Chicago. Illinois 60690 i

December 29, 1981 '

//

'b Mr. A. Schwence r, Chief RECEIVED Licensing Branch #2 2 -

Division of Licensing -

JAN4 1982> .

U. S. Nuclear Regulatory Commission & N amit gygg g,,,,, =

Washington, DC 20555

,d kam

Subject:

LaSalle County Station Units 1 and 2 Proposed FSAR Change Concerning End-of-Cycle Recirculation Pump Trip NRC Docket Nos.-50-373/374

Dear Mr. Schwencer:

The purpose of this transmittal is to provide a proposed revision to the LaSalle County Station FSAR. This proposed change provides the necessary support for resolution of an open Technical Specification item.

The open Technical Specification item concerns the response time o f end-of-cycle recirculation pump trip (EOC-RPT) actuation instrumentation. Currently the response time change from 0.140 seconds to 0.190 seconds is shown as an open item in the LaSalle Technical Specification pending submission of an FSAR change incorporating the 0.190 second value.

It is our understanding that this information should provide a basis for clearing the Technical Specification issue on EOC-RPT.

The attached proposed changes will be documented in an Amendment to the FSAR.

If there are any questions in this regard, please contact this office.

Ve ry truly yours, bb C. E. Sa rgent Nuclea r Licensing Administrator Attachment cc: NRC P,esident Inspector - LSCS 3110N b['

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3 O h Tut bine gcner ator PLU ttip g { d[ @

initiates main tur bine bypass system operation.

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0 Fast turbine control valve

{. closur e initiates reactor scram.

O Past turbine control valve closure initiates a recirc pump trip (RPT).

0.07 Turbine Control valves closed.

0.1 Turbine bypass valves start p

.- to open.

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[ '.i~ ? ' ' - . ; c i . a ator c::cutc L t t:. ,er s IIecreasing in-cure flow ecca C [u s a r ic::c al circulation.

1,35, 1.52, 1.67, ' .ef "ilvas activate sequentially 1.J3, . :i 2.07 in _ t o .. y .> : 1, 2, 3, 4, and 5.

4.08 High water level tr ip L8 initiates feedwater trip.

(Est) 5.2, 5.6, 6.0, Relief Valves close sequentially 6.0, 6.2, and 7.1 in groups: 5, 4, 3, 2, and 1.

I 24.8 (est)* Turbine bypass valves star t to close.

32.5 (cst)*

~

-s S;p ce ulver c'c ~1 31.56* Turbine bypess valves reopen on pressure signal.

38.31* L2 vessel water level trip initiates ::SIV's.

L2 vessel water level trip initiates RCIC and HPCS (not simulated).

• Event and times are typical of FEDY solution for this c. vent.

They are included here to record the time-line of events l'eyond the 15 second results fron ODYU mcdel.

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e tr . The . c y m. _ of mts i ,r lo;s of , .. J .t lead accur.p<.nied by failt,ce of the tur!>ine bypans

- valves (Figure 15.2.2-2) is as follows:

l TIME '8 (sec) EVENT

-0.015 (approx) T'ir b i a c -g e ne r a tor detection j of loss of generator load.  :

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-'u r b i c.c -g e n e r a t or power load 0

unbalance (PLU) devices trip to i citiate turbine control valve fast closure.

O Turbine bi pas valves fail

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v.U, - s . .ir m ne coa t t u t c a ,t v e s c u. wa .

/ pl-4' O,l9 } Eecirc pai.e ac; tor circuit breakers open thus decreasing in-coce flos to natural circulation.

1.09, 1.20, 1.31, Relief valves actuate sequentially 1.45, and 1.60 in groups: 1, 2, 3, 4, and S.

lm-t) 7  ;, f.e, =

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c 1 w.. cinco cc ,

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, ~, 1 11.38, 12.56* Re li e f calvcs actuate sequentially in grcups: 1 and 2.

(Est) 17.6, 18.8* Relief valves close sep.entially in groups: 2 and 1.

24.3* Group 1 Relief Valves actuated.

3 2.0 (es t)

• Grocp 1 ~ ~; '_ i i f "a l v e s c lo s e d .

" vents and t ig.e s are tjpical of EDI solution fo- i. Y s c c . nt.

They are included here to r3 cord th.; u:..e-line of events .-;ycnd the 15 second results fran GDYN 1.cdel.

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t. c_ -

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'.Y 1(81

- Tulbine trip initiates bypass operation.

0.01 '4ain turbine stop valves reach 90E open pesition and initiato reactor scram trip.

4ain turbine stop valves reach 90c open position and initiate a tecirculation pump trip (RPT).

0.10 Turbine stop valves closed.

Turbinc lypass valvec start to

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a.

. . .. . .- , , s. ,

nd 5.

4.53 rec s.tct trip on high water level i L8) .

(Est) 5.2, 5.5, Relief valves close sequenti-5.9, 6.2 and 7.0 ally by groups: 5, c, 3, 2, and 1.

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nitia'.cs to clore

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.a l .

32.2 (est) Tu-bina bypass closed.

38.67 Low level trip (L2) initiates a main steam line isolation.

Low level trip (L2) initiates RCIC and HPCS (not simulated).

39.23 Turbine bypass reopen on pressure increase at turbine inlet.

9

= 7 3 -

6

r; 3 i

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. Ev gs ODYN - Turbine Trip ',;ithoat ncy Classification 15.2.3A 15.2.3A.1 Tdentification of Causes and Freauewill iniLiate lfunctions turbine or nuclear systemmoisture ma separator and A variety of Some examples large are: vibrations, operator a turbine trip. low condenser vacuum, heater drain tank high levels, fluid pressure, lockout, loss of control and reactor high water level. an infrequent is categorized as to be as follows:for this A turbine trip without bypassThe6 frequency years. The isofbasis expected the bypass incident.

0.0064/ plant year with 11TBE of 15that the f ailure rate d rejection.

frequency prediction theissame as for generator loatrip frequency 1.22 events of

'alcce is 0.0048,'*5 'he turine - of 0.0064 pernplant ear.

n1 c yser

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c- {

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Tae s..s._ ice o;

failure of c..; ,; .>

accanpanying is as follo./s:

15.2.3-2)

Event Time -

(sec) Turbine trip initiates closure 0 of main stop valves.

i to Turbine bypass valves fail c1 r-te.

0.011 Main turbine stop valvc;90 reactor scram trip.

Main turbine stop valv trip (RPT a recirculation pump Turbine stop valves closed.

0 .1 -

Recirculation pump noter ciretj f

0E[ O . /9 breakers open causing decre in core flow

")' - tion.

19.'-17

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