ML19221A382

Discusses Methods of Adequate Core Cooling Through Natural Circulation in Event of Loss of Operating Reactor Coolant Pressure

ML19221A382
Person / Time
Site:	Crane
Issue date:	04/22/1979
From:	Office of Nuclear Reactor Regulation
To:
References
OSP-790422, NUDOCS 7905220421
Download: ML19221A382 (7)

Text

"

E.P - e e.e v.

/co s

/

! ST' 5 W, b

d EP Loss of Operating RCP O

Successful flatural Circulation O

h_

L 7'M l.0

Purpose:

i n

8.o To provide adequate ccre cooling through natural circulation in the

_. _.n..ev en t. o f. l o s s. o f..the opera t i ng.RCP ^^.,, _ _ _ _ _.

_.____;.- -- - -- < :. _ :. y r~

... - ' * ~ :._.-.-.L' _ _,.: ~

'.2.0.. References "

T '...

~

.: j.

..iG.D.. : *

• _... ~...12.,_ ). T:1.'.. _.,.. a

_.l.

.- - ; :. ~ : : _ _-.= 9::.~-: - =-Nk.y ~d..- ?- ~- i_i-

. Oes cr ip tioa-....:.r~.. J.. i. c. ?. :EQ.e.-fe_,. :_.x. - -.r R e f. I!o c _-. t

... Loss ofQeactor Co.clant Pumps ot: 8 April.,19 79_,._

.---. _.. Contingency Pl an C-1,2,3 Ref. A Bill Lowe to (Illegible) Telecon flote of 0800, 4/12/79 Ref. !180 NDT Pressure / Temperature Curve Ref. #10 tlatural Circula tion - Minimum RCS Pressure vs th'at curve with saturation curve added Ref. f48 Preparation fer an initiation of

(.

natural circulation.

Ref. #168 i

Effect of Partial Flow Blockage on it. C.

~ Ref. #156 RCP Startup Procedure (S&W procedure 15, Rev. 4)

Ref. fli Loss of RC Flow /HPI i

Ref. p(BMI) 77 Lua: nf RCP - Successful Natural Circulation (B&W 486, 4/19/79)

Ref. !TEG 071 Loss of Reactor Coolant Pump (R. Keaten 4/19/79) 3.0 Limitations and Precautions 3.1 Orarational limits of RCP. with backup RCP's available:

a.

frame v uration exceeds 5 mils.

~

or

'" ~'

b.. sha f t vibra tiori exceeds '30~ mil s * ~

and.

upper seal leakage & return flow increases to grea ter than 1.9 GPM.

b 7 9 0-5 2 2 0 4 2t 160 008

.2 C'

T-

- EP-32 Rev. 1 4/22/79 t

3.2 Operational limits of RCP with no backup RCP available.

(

a.

Sha f t vibration > 70 mil.e or b.

Upper seci leakage > MU system capability to maintain RC system water level.

4.0 Symptoms

..-, Flow in the operating loop. decreases or becoir.es erratic

. 4.1 RC

.-.,m.

C ~ ~ ~ " ' " '4. 2 Com;ilete 13ss of RC Tlofibperating loop.-E-

-' ~~'- "

-" T ' ~.~

, -. s. 9 _

__ _,. _ _.._. _... _,.. -.3_.

...; 3.. ;_..

-g.g.r 4

3._ RC_ Pump Tr,_p annunc1ator.;.. _. __ _ ;..

=-..__..;_ =. :- ;- ; ;p.-;..;. _.:..L: -

=....... -

4.4 RCP. li.mits.(section 3). exceeded.

4.5 Indications the RCP has stopped as observed by no running current (amps) or vibration.

NOTE:

Initial Condition Heat removal through A OTSG in Steaming T:cde B OTSG H "2

9"

1. Y-2 Feedwater to OTSG supplied thru u.a g/;..c y-FH nozzies.

M 5.0 Immediate Actions t

~~

5.1 Attempt to establish natural circulation 5.1.1 Icriediately begin raising RCS pressure to approximately 900 psig +_ 100 psig (to increase margin to saturation).

5.1.2 Trip the turbine 5.1.3 Without altering the feedwater lineup or fiow rate allow, OTSG "A" level to slowly increase to 430" on the wide range instrument.

Secure feedwa'.er flow, and allow OTSG "A" level to decrease to 400".

Re-establish feedwater flow at the previous rate to increase level to 430".

Repeat as necessary to maintain level between 400" - 430".

NOTE 1 - Following the above actions and when equilibrium conditiens are established, RCS temperature Tc should stabilize.at about 200 0F.

• }

e 160 009

. EP-32, Rev. 1 4/22/79 Note 2 - Naturcl Circulation is indicated by an increase in RCS A T to a new value grea ter than the approximately zero

- (

A T of forced circulation.

This AT is expected to be approximately 10 to 25 when equilibrium conditions'of ficw have been achieved.

' nitially, however, A T uill increase 0

to greater values which could be as much as 15 to 40 F in the five to ten minute period af ter the loss of RCP, followed by a decrease to th.a equilibrium A T.

The a.T values in this paragraph'.are provided for information.only and are a result of-

--- -interpretat~ ion' of analytical data.

It.should take about- ' - ;;- - - - - - #

--._ ~ 25.t.5 35 luin. ' to es tablish' natural circul ation. ~ ~ '--.,,, _

' ' ~

r~

~

--=== - = -:-

Note 3. g' The_sys tem will. respond slowly to changes 7while.._.;. :-._-

~

..in the. natural.circulatidn mode.- The loop transport-time is about 20 minutes, therefore, change's in steam demand and ""~'

-^ '

~

feed rate should be made slowly and the system should be given time to equilibrate before additional changes are made.

5.1.4 Manually record and plot T, T and T every h

c stm twenty (20) minutes.

Read and record all operable in-core thermocouples every tien (10) minutes.

5.1.5 If any of the (4) criteria provided ~below are exceeded, adequate Natural Circulation has not been established, therefore, proceed to step 5.2.

in the loop with the OTSG in the steaming 5.1. 5.1 If TH

{

- mode exceeds 420 F, go to step 5.2.

0 5.1.5.~2 If any thermocouple excess,1000 F go to step 5.2.

5.1.5.3 If any three (3) thermcouples have readings exceeding 800 F go to step 5.2.

0 E.,

S cc F m= w ~ 2 "

e w

2 5.1.5.4 At least 6 thermocouples must be below-C49 F, otherwise go.to step 5.2.

NOTE:

After natural circulation has' be'en established wili be nearly.

it is expected that THowever,H and T stm equivalent.

T snculd not be less thin stm T for natural circulation to occur.

In making the cabove ccmparisons, an instrument error of up to 1 5 F must be considered.

.i-~T

- - ~ -

~

~

' 1601 Oj 0' L

~

• =.

LP-32, Rev. 1 4/ u/ d

- s After t'mperatures have sto ilized (1/2 - 1 hr expected),

5.1.6 e

decrease steam flow from the "A" OTSG by shutting the MS supply valves to the MSR "A", MS-V35A and MS-V35A.

NOTE:Following the above actions and when equilibrium conditions are established, T from the plot in step c

5.1.4 should have increased to about 205 of.

5:2 'I f maturatEircultion-is-not-estab-1ished ; attempt -to-regrin 2--------

flou by starting RCP'-s' in the' fol1owing saquence.,J."..'...f,;

2;,_

,;.~.-~~.

Y.'U57.iYI'Eh. -

5.2.1 ' It'tedpt-to' res ta'rt"RC-P 2'A as fUl1 ot-is : -:'.;M~55th.~455-2 '.2:I:hi.'8 -

.----:=-...-.=..=....__..._-..-..._._-.=.~.=..=--..--_..---

- g _~...-.

Y

- - ~.

C' a)

Start and run RC-P-2A High Pressure lift 1 and B

-top oil pumps s h c/

edl/h /-

x.Js p -p.

NOTE: The motors c.n be started with acceptable risk without the backstop -lube oil pumps.

RC pressures between 800 and 1200 P.S.I. should allcw operatic-n of the motors without the high pressure oil lift systec.

At pressures below 800 psi, start up without high pressure lif t system may not be successful but may be attempted.

b)

Start RC-P-2A.

c)

Open or check open seal return valve MU-V-338.

Three start attempts are allowed from cold condition.

NOTE:

5.2.2 If RC-P-EA cannot be started, attempt to start RC-P-1 A as follows:

a)

Start and run RC-F-1 A High Pressure lift and Backstop j

Oil Pumps b). Start RC-P-1A c)

Open/ check open seal return valve MU-V-33A.

5.2.3 If RC-P-1 A cannot be started, start RC-P-18 or 25 l

as follmws:

a)

Obtain HP person to accompany A.0. to establish seal injection on RC-P-lB and 2B by opening MU-V-379 and MU-V-380.

HOTE:

RWP must be prepared each shift designating personnel who will make entry.

' i-;.-.

.-.-_g,-

160 0\\i

~ ;....

s

-5 EP-32, Rev. 1 4/22/79

~ '.

Start AC Oil Lif t and AC Backstop Pumps for RC-P-1B 5.2.4 I

and 23.

5.2.5 Verify intermediate and NSCCF is, perating.

Verify Seal Injection Flow on RC-P-1B and 28.

5.2.6 5.2.7 Open MU-V33 C & D.

Verify RC Pump Seal staging by

,,_,,,,,,4

.....,._....._.._ __. obs e rs i.n g.s ea L,ca y i ty p re g u re. _

5.2.8. Verify RC Pump Seal Return Flow (.< 1.91 gpm), on RC-P 18.

- - - -- - +- I ' '.:. : ~.:

.a--."..-:..-

.-r.

~ " -

a n d 2 B. --. f...

c..... -. _

. -.. s....

_7d;... J. ;

,21. p, c.. ---.

. g...-.2-

=

i_.. -

MWith st)J_s 2.2.2 through f.2.7 complete, start

- - 5 g g p, RC-P _T. cA V g.

5.C X If RC-P N art attempt unsuccessful, start RC-P-2 W lb 5.2.11 Monitor the following during startup through the transient and thereafter for proper indication.

Upper seal cavity pressure, lower seal cavity pressJre, se?.I return temperature. upper seal leakage, seal return flow, pump. shaft vibration and motor bearing temperatures.

5.2.12 Close MU-V33 cn non-operating pumps.

5.2.73 Close seal injection valves on all but star.dby pump and readjust seal injection to minimize mai.eup.

5.2.14 Secure oil lift pumps on all non operating pumps.

5.2. IS If an RCP was successfully started, return RCS pressure.

and "A" OTSG level to the previous condition.

5.3 If no RC pumps can be started, attempt to establish natural circulation.

5.3.1 Verify RCS pressure is 900 + 100 ps ig a nd "A'"

OTSG level 400-430".

Adjust RCS pressure and OTSG level to reach andmaintain those parameters.

5.3.2 Allow temperatures to stabilize for 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />.

During ~

this period of time, read and record all operable thermc_auples every ten minutes.

.~. _ -l.

. 3 ~..,

..s...

L

~

160 0\\2 N

I ' ' * '. s EP-32 Rev. 1 4/22/19 l

~

~

5.3.3 If any thermocouple exceeds 1200 F prior to successfully establishing Natural Circulation, go to step S.4.

(,..

0 5.3.4 If any 3 thermocouples exc.eed 1000 F prior to successfully establishing Natural Circulation, go to step 5.4.

5.3.5 If 6' any time during stabilization or natural in the loop witn the OTSG

~

..., ci.rculaticn atte. pts Th m

in the steaming r.. ode. exceeds 5000F. proceeed to

[ 2.57 s tep 5.4.

- e

= * ~ ~ ' __.... '.

- - :. + : - =. %. ' ^ :. p.

.. ;; _.. ~ - '.

.~

... ij0TI;. Continue. plotting.Tg,.-T >C. nd Ts tni,a s p n. -, - =- g :r --

+g h _=,. :.. -

. - 7,_ w..,,

i_...._.......

s tep -5.1.d.

~

5.4 If natural circulation :r r.qt established, go into liPI per EP33, starting with Step 3.2.

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5

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=

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C 1P = 1000 pf g

LD -

F = ~800 psi i

3?= 60C gi 6

F=

'00 pi 5

5P= 200 pi

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05 -

+Expe::td Core s;

' Press:re Drey.-

.a Tin = 223'E E0-g

_ 4 g - - - - --.

Bed Porosity =

0200 i

.2 3

4

~,i Pebble Size =

0.00380 fi w wia Assmbh Pover = 1430 Blu/see u

1

-as b b

b b

b b

b b

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