ML20056D815

Proposed STS 3.1.7, Standby Liquid Control Sys

ML20056D815
Person / Time
Site:	05200002
Issue date:	08/11/1993
From:	GENERAL ELECTRIC CO.
To:
Shared Package
ML20056D813	List: ML20056D812 ML20056D815
References
NUDOCS 9308180049
Download: ML20056D815 (11)

Text

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SLC Sy0 tem 3.1.7 a 3.1 RIACTIVITY CONTROL SYSTEMS 3.1.7 Standby Liquid Control (SLC) system  !

i LCO 3.1.7 Two SLC subsysteres shall be OPERABLE.

I APPLICABILITY: MODES 1 and 2,

}

ACTIONS ,

. CONDITION REQUIRED ACTION ' COMPLETION TIME i,

A. Concentration of A.1 Restore concentration 72 herrs -

boron in solution of boron in solution i not within limits. to within limits. 3, 10 days from f discovery of failure to meet  !

the LCO

3. One SLC subsystem B.1 Restore SLC subsystem 7 days =f inoperableh for. to OPERABLE status. - -

i reasons other than M '

Condition ATT" g 10 days from -'

discovery of ,

failure to-meet the LCo '!

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C. Tvo SLC subsystems C.1 Restore one SLC 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />s-inoperable 3fer subsystem to CPERABLE reasons other than [

status. '

Condition A [ ,

• I D. . Required Action and D.1 Be in MODE 3. 12' hours '

associated Co:tpletion  !

Tic.e not met. 'I ABWR TS 3.1-1 Rev. O, 11/4/92 9308180049 PDR ADOCK 930811 (G

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SLC System

, 3.1.7 [

t SURVEfLLANCEREQUIREMENTS SURVEILLANCE FREQUENCY-SR J.1.7.1 Verify available volume of sodium O 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> pentaborate solution is 2: 23.1 m (6103 gallons) '

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SR 3.1.7.2 Verify temperature of sodium pentaborate 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> solution is within the limits of Figure 3.1.7-1.

1 W SR 3.1.7.3 Verify tamperature of pump suction piping

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24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> -h o F

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is within the limits of (Figure 3.1.7-1).

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SR 3.1.7 Verify the concentration of boron in 31 days solution is within the limits of Figure 3.1.7-1. M 5 Once within st$tJ it SLC bei +1 D l1 de b bv2cs*< C *) .fue /Yo op -

• 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />'atter b

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dded to solution

$l1C JL C. ban /f, f},e fife dis e 1,4 e f s'p, n f//c J o i,'4 de m ,,, e -a/.je J a .c /e, an ./ m -

4l5 o $14 ) Ho ben b lv ?co n once within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> after I solution  : ,-

temperature is  !

restored within 'l the limits of .f

' Figure {

3.1.7-1

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ABWR TS . . 3.1-2 Rev. O, 11/4/92 -i t

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, SLC System f 3.1.7 i

SURVEILLANCE RIQUIRIKENTS (continued) I 2

SURVEILLANCE FREQUENCY  !

SR 3.1.7.[ f Voperated, erify each SLC subsystem manual, power and automatic valve in the flow 31 days path that is not locked, sealed, or I otherwise secured in position is in the 'I correct position, or can be aligned to the  !

correct position.  !

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SR 3.1.7.[(Ve fy each pu=p develops a flow rate h pl.0; ;p at a discharge pressure It i rW ~e with :t; 2 r; w ; p-ig, Inge 3;  ;

F6 X3 /Ce*j bO O A [3' - Pe,.f 3 _ C *.

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92 days  !

SR 3.1. 7 / Verify flow through one SLC subsystem from e- -[18[ months on pump into reactor pressure vessel. a STAGGERED 2 TEST BASIS SR 3.1.7 Verify that simultaneous operation of both ,d18[ months '!

pumps develop a flow rate 6.30 1/s (100 gpm) at a pressure of SI unite <

(1223 psig).

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SR 3.1.7.9 Verify all heat traced piping between [18) months l storage tank and pump suction is unblocked.

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Once within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> after i

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1. 3,I' '$ ' solution

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• temperature is restored within the limits of j

[ Figure 3.1.7-1] ,

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ABWR TS. 3.1 3 Rev. O, 11/4/92

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SLC Syctam 3.1.7 SURVEILI.ANCE REQUIRIMENTS (continued)

SURVEILLANCE TREQUENCY continued)

SR 3.1.7.10 Veri' . m pentaborate e. ' ment is Prior to 60.0) atom percent B-10.

(93 addition to C tank 4 e ABWR TS 3.1-4 Rev. O, 11/4/92

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Reactivity control' systems standby Liquid control (sLC) system  ;

EASES l BACKGROUND i The SLC System is designed to provide the capability of k bringing the reactor, at any time in a fuel cycle, from  !

full power and minimum control' rod inventory (which is at I the peak of the menon transient) to a suberitical '

condition with the reactor in the most reactive menon 4 free state without taking credit for control rod '

movement. The SLC system satisfies the requirements of 10 CFR 50.52 (Reference 53.1.7-1) on anticipated I transient without scram (ATws).

The ELC r~ stem consists of a boron solution storage tank, twc pc , ,

displacement pumps, two ' motor operated injec Q ~ {

- ves, which are provided in parallel for redundancy, and associated piping and valves used to transfer borated water from the storage tank to the ~I i

reactor pressure vessel (RPV). The borated solution is_

discharged through the "B" Eigh Pressure Core Flooder i (RPCF) subsystem -h8e f'$ C P APPLICABLE The SLC System is automatically initiated. The SLC f SAFETY ANALYSES System is used in the event that not enough control rods can be inserted to accomplish shutdown and cooldown in -

f the normal manner. The SLC System injects borated water-into the reactor core to compensate for all of the various reactivity effects that could occur during. plant i l

f operation. To meet this objective, it is necessary to inject a quantity of boron that produces a concentration '

of 850 ppe of natural boron in the reactor core at 21*C (70*F). To allow for potential leakage and imperfect mixing in the reactor systes, an additional amount of f A

boron equal to 25% of the amount cited above is added i

(Reference R3.1.7-2). The temperature versus 1 concentration limits in Figure 3.1.7-1_ (in the I j

accompanying LCO) are calculated such that the required concentration is achleyed accounting for dilutio'n in the

. RPV with normal water level and including the water  !

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volume in the residual heat removal shutdown cooling piping. This quantity of borated solution is the amount j

that is above the pump suction shutoff level in the boron

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solution storage tank. No credit is taken for the portion i 4

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. . i of the tank volume that cannot be injected.

l The SLC System satisfies the requirements of the NRc Policy Statessat because operating esperience and probabilistic risk assessment have generally shown it to be important to public health and safety. i LCO The OPERABILITY of the SLC systes provides backup capability for reactivity control, independent of normal reactivity control provisions provided by the control {

rods. The OPERABILITY of the ELC System is based on the I i

conditions of the borated solution in the storage tank  ;

and the availability of a flow path to the 177, including l the OPERABILITY of the pumps and valves. Because the '

minimum required boron solution concentration is the same

• for both A'tws mitigation and cold shutdown (unlike some  ;

I previous reactor designs) then if the baron solution concentration is less than the required limit, both SLC ,

subsystems shall be declared inoperable. Tteo sLC

• subsystems are required to be OPERARLE, each containing an OPERABLE pump, a motor operated injection valve, and associated piping, valves, and instruments and controls l to ensure an oPERARLE flow path. t APPLICABILITY In MODES 1 and 3, shutdown capability is required. In k teoDEs 3 and 4, control rods are only allowed to be withdrawn under special Operations LCo 3.10.3, " control Rod Withdrawal-Rot Shutdown," and LCO 3.10.4, ' Control Rod withdrawal-Cold shutdown," which provide adequate controls to ensure the reactor remains subcritical. In  !

neoDE 5, only a single control rod or control rod pair can  !

he withdrawn from a core cell containing fuel assemblies. -

Demonstration of adequate SDei (LCO 3.1.1, "SEUTDOWN L MAAGIN (SDet)") ensures that the reactor will not become critical. Therefore, the SLC Systes is not required to be  !

It(SG A T CPERARLE during these conditions, when only a single l

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h./ control rod or control rod pair can be withdrawn.

8 ACTIoxs Q -  ?

If one sLC system subsystem is inoperable, the inoperable i subsystem must be restored to OPERABLE status within 7 days. In this condition, the remaining OPERABLE I subsystem is adequate to perform the shutdown' function. t However, the overall reliability is reduced because a i

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single failure in the remaining OPERABLE subsystem could 1 i

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If the boron concentration is less than the required limits given in Figure 3.1.7-1 the concentration must be  !

restored to within limits in 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. For ATWS prevention / mitigation the ABWR features;an automatic rod insert (ARI) which utilizeandsensors er electrical and logicinsertion that areofdiverse FMCRDs andboth of independent of the reactor protection system; an ATWS recirculation pump trip (RpT)]and automatic initiation of SLCS under ATWS conditions (Ref.jB3.1.7-3). These features ,

provide the ABWR an ATWS prevention and mitigation '

capability well beyond previous BWRs. Because of the low  !

probability of an ATWS event, the ATES prevention / mitigation features and that the SLC System capability still exists for vessel injection under these conditions, the allowed Completion Time of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> is acceptable and provides adequate time to restore concentration to within limits. The maximum Completion Time of 10 days is allowed for this LCO in the event of multiple condition Entry.

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result in reduced SLC system shutdown capability. The 7 day Completion Time is based on the availability of an OPERABLE subsystem capable of performing the intended SLC '

system function and the low probability of a Design Basis Accident (DBA)'or severe transient occurring concurrent '

with the failure of the control Rod Drive System to shut down the plant. The maximum Completion TLme of 10 days is allowed for this LCO in the event of multiple condition '

entry.

C %.1 - 7 If both SLC subsystems are inoperable, at least one subsystem must be restored to CPERABLE status within '

8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />. The allowed Completion Time of 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> 'is considered acceptable, given the low-probability of a DBA or transient occurring concurrent with the failure of the control rode to shut.down the reactor.

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If any Required Action and associated completion Time is not met, the plant must be brought to a MODE in which the LCO does not apply. To achieve this status, the plant must be brought to MODE 3 within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. The allowed L

completion Time of 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />' is reasonable, based on

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operating experience, to reach MODI 3 from full poway '

conditions in an orderly manner and without challengIhg plant systems, aend SURVIILLANCE SR 3.3.7. m 3.1.7.2 3 :fn  :.;.7 D -p REQUIREMENTS g33 g i SR 3.1.7.1 thre.;h SR 3.1.1.1 are 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> surveillances, -

verifying certain characteristics of the SLC System.  !

(e.g., the volume and temperature of the borated solution' in the storage tank), . thereby ensuring the SLc system CPERABILITY without_ disturbing normal plant operation.

These surveillances ensure the proper borated solution and toeperature 4ee*= ding th: t; r;s;tes; Of the M t

, ;;;;;vu ylping, are maintained.' Maintaining a mi' imum n i specified borated solution temperature is important in ensuring that the boron remains in. solution and does not.

precipitate out in the storage tank. r in th: 7- ;

ti n r r' 7 The 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> Frequency.of these 3Rs is f

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based on operating experience that has shown there are I relatively slow variations in the measured parameters of volume and toeparature.

3 SR 3.1. 7. / - JL i This Surveillance requires an examination of the sodium i pentaborate solution by using chemical analysis to ensure the proper concentration of boron exists in the storage '

tank. SR 3.1.7.k)must be performed anytine boron or water ' ,

is added to the storage tank solution to establish that the boren solution concentration is within the specified '

limits. This Surveillance must be performed. anytime the '

temperature is restored to within the limits of Figure 3.1.7-1, to ensure no significant boron '

precipitation occurred. The 31 day Frequency of this -

Surveillance is appropriate because of the relatively slow variation of boron concentration between surveillances. i 4/

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SR 3.1.7./ verifles each valve in the system is in its correct position. Verifying the correct alignment for manual, power operated, and automatic valves in the SLC System flow path ensures that the proper flow paths will '

exist for system operation. This Surveillance does not '

apply to valves that are locked, sealed, or otherwise  ;

secured in position, since they were verified to be in  !

the correct position prior to. locking, sealing, or securing. This verification of valve alignment does not apply to valves that cannot be inadvertently misa11gned, such as check valves. This SR does not require any testing or vaive manipulations rather, it involves verification that those valves capable of being mispositioned are in the correct positions. The 31 day  !

Frequency is based on engineering judgment and is $

consistent with the procedural controls governing valve operation that ensure correct valve positions.

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Comonstrating each SLC system pump develops a flow rate 2 11.4 m '

3 gh(50gpm) at a discharge pressure 2 86.0 Rg/cm g (1223 poig) ensures that pump performance has not degraded during the fuel j cycle. This minimum pump flow rate requirement ensures that, when combined with the sodium pentaborate solution concentration requirettents, the rate of negative reactivity insertion from the SLC System will adequately compensate for the positive reactivity effects encountered during power reduction, [

cooldown of the moderator, and xenon decay. This test confirms one point on the pump design curve, and is indicative of overall performance. Such e inservice inspections confirm component OPERABILITY, trend performance, and '

detect incipient f ailures by indicating abnormal perfomance. The Frequency of f this surveillance is . h r:::h .:: 21" "- - =-

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u 92 days.

i 6 7 SR 3.1.7.k and SR 3.1.7./ W These Surve111ances ensure that there is a functioning i flow path from the boron solutior. storage tank to the ,

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RPV he pump and injection valve tested should be  !

alternated such that both complete flow paths are tested i every 36 months, at alternating 18 month intervals. The I surveillance may be performed in separate steps to i prevent injecting boron into the RPV.'An acceptable method for verifying flow from the pump to the RPV is to. -

pump domineralized water from a test tank through one'SLC i IA 5 4 3. /.7. subsystem and into the RPV7The 18 month Frequency is- A rt

$on S Lc s basedontheneedtoperformth@surveillanceunderthe 4 j

, ppmpS (A f- 4, conditions that apply during a plant outage and the I

.f 43 p d ho t- potential for an unplanned transient if the surveillance 65) .j

- Simu Ltc4 4 t o u.5 were performed with the reactor at power. Operating i j DecM-fi O A, experience has shown these components usually_ pass the ,

d surveillance test when performed at the 18 month [

rroquency; therefore, the Frequency was concluded to'be

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acceptable from a reliability standpoint.-  !

r.;t.eting thn .. :.. t t;;::d pipir.f i:r : - St.e .

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hat the suction piping is unblocked is to pump fro- Io l st. e tank to the test tank. The 18 month T s eney is acceptab since there is a low probabi that the subject pipin ill be blocked due precipitation of i

the boron from so on in tb eat traced piping. This is especially true in of the daily toeperature - l verification of this ping r ired by SR 3.1.7.3. {

llowever, if, in rforming SR 3.1. . it is determined i that the te.- rature of this piping has en below the specift minimum, this surveillance must be formed ,

one ithin 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> after the piping temperature i Q E RERsacs s [

1 restored.within the limits of Figure 3.1.7-1.

N b 3' I' 7' l. 10 CFR 50.62. '

s' d, ABWR SSAR,'Section 9.3.5.3.

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