ML20236S146

Proposed Tech Specs Supporting Mods to Standby Liquid Control Sys Being Implemented to Comply w/10CFR50.62 & Correcting Ref Made to Figure in Tech Specs Deleted as Result of Proposed Amend

ML20236S146
Person / Time
Site:	Quad Cities
Issue date:	11/17/1987
From:	COMMONWEALTH EDISON CO.
To:
Shared Package
ML20236S131	List: ML20236S129 ML20236S146
References
NUDOCS 8711240250
Download: ML20236S146 (10)

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1 ATTACHIGGIT 1 i

l PROPOSED CHANGES TO APPENDII A.-

l TECHNICAL SPECIFICATIONS'FOR OUAD CITIES STATION UNIT 1 FACILITY OPERATING LICENSE DPR-29 Revised Pages: 3.4/4.4-1 3.4/4.4-2 3.4/4.4-3 3.4/4.4-3a Figure 3.4-1 4

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QUAD-C8 TIES DPR-29 3.4/4.4 STANDBY LIQUID CONTROL SYSTEM LlMITING CONDITIONS FOR OPERATION SURVEILLANCE REQUIREMENTS-Applicability: Applicability:..

Applies to the operating status of the Applies-to the periodic testing require-standby liquid control. system. ments for the standby. liquid control system.

Objective: Objective:

To assure the availability of an indepen- To verify the operability.cf the standby dent reactivity control mechanism. liquid control system.

SPECIFICATIONS A. Normal Operation A. Normal Operation During periods when fuel is in the The operability of the' standby liquid reactor and prior to startup from a control system shall be verified by.

cold condition, the standby 11guld performance of the following tests:

control system shall be operable except as specified in Specification 1. At least once per month-3.4.B. This system need not be oper-able when the reactor is in the cold Demineralized water shall be  !

shutdown condition, all control rods recycled to the test tank. Pump.

are fully inserted, and Specification minimum flow rate of.40 gpm 3.3.A is met. shall be verified against a 'l-system head of 1275 psig.

2. At least once during each opera-ting cycle '

Manually-initiate the system, except the explosion valves and pump solution in the recircula'-

tion path, to demonstrate that the pump suction line from the storage tank is not plugged.

Explode two of s1x-charges or l two of four charges manufactured.

In the same batch using the per-manent system wiring to verify-l proper. function. .Then install the untested' charges in the explosion valves.

Demineralized water shall be

. injected via a test connection-into the' reactor vessel to test that valves (except explosion valves) not checked by the recirculation test'are not clogged.

0624H 3.4/4.4-1 Amendment No.

(TJAD-CITZ ES DPR-29' Test that the setting of the system pressure relief valves is between 1455 and 1545 psig.

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3. Disassemble and inspect one explosion valve so that;it can be established that the' valve is' .,

not clogged. Both valves shall_.

be inspected in the course of-

~two operating cycles.

4 B. Operation with Inoperable Conditions B. Operation with Inoperable Components From and after the date that a redun- When a component becomes inoperable, i dant component is made or-found to be its redundant-component shall be inoperable, Specification 3.4.A shall demonstrated to be operable immedi-be considered fulfilled and continued ately and daily thereafter.

operation permitted provided that the j component is returned to an operable 1 condition within 7 days. ]

C. Liquid Poison Tank-Boron Concentration C. Liquid Poison Tank-Boron Concentration The liquid poison tank shall contain The-availability of the proper a boron-bearing solution of at least boron-bearing solution shall be' veri-3733 gallons of at least 14 WT fled by performance of the'.following percent sodium pentaborate tests-  ?

Decahydrate (Na2 B10 016 - l At least once'per month

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l 10H 2 0) at all times when the 1.

standby liquid control system is required to be operable and the Boron concentration shall-be- .; '

solution temperature shall not be determined. 'In addition, the less than the temperature presented boron concentration shall be

in Figure 3.4-2. determined any time water or I boron are added or if the a D. If Specifications 3.4.A through C are solution temperature drops below )

not met, an orderly shutdown shall be the limits specified by figure  ;

initiated and the reactor shall be in 3.4-2.

the cold shutdown condition within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. 2. At least one per day i

Solution volume shall be checked.  !

3. At least_once per day The solution temperature shall.

be checked.

0624H 3.4/4.4-2 Amendment No.

QUAD-CITIES DPR-29 3.4 LIMITING CONDITIONS FOR OPERATION BASES A. The design objective of the standby 11guld control system is to provide the capability of bringing the reactor from full power to a cold, xenon-free shutdown assuming that none of the withdrawn control rods can be inserted. To meet this objective, the liquid control system is designed to inject a quantity of boron which produces a concentration of no less than 600 ppm of boron in .the reactor core in approximately 83 minutes with imperfect mixing. A boron concentration of 600 ppm in the reactor core is required to bring the reactor from full power to 3%

Ak or more subcritical condition considering the hot to cold reactivity swing, xenon poisoning and an additional margin in the reactor core for imperfect mtxing of the chemical solution in the reactor water. A normal quantity of 3,321 gallons of solution having a 14% sodium pentaborate concentration is required to meet this shutdown requirement. .

For a required pumping rate of 40 gpm, 3321 gallons of at least 14 HT percent solution will be inserted in approximately 83 minuter. This insertion rate of boron solution will override the rate of reactivity j insertion due to cool down of the reactor following the :'enon peak, i Two pump operation will enable faster reactor shutdown for ATHS l

events. The monthly pump minimum flowrate test shall require a minimum flowrate of 40 gpm. This requirement, combined with the solution concentration requirements of at least 14 WT percent, will demonstrate  :

that the Standby Liquid Control System meets the requirements of 10CFR50.62.

i Boron concentration, solution temperature, and volume are checked on a frequency to assure a high reliability of operation of the system <

should it ever be required. Experience with pump operability indicates l that monthly testing is adequate to detect if failures have occurred. '

The only practical time to test the standby liquid control system is during a refueling outage and by initiation from local stations.

Components of the system are checked periodically as described above and make a functional test of the entire system on a frequency of less ,

than once each refueling outage unnecessary. A test of explosive 1 charges from one manufacturing batch is made to assure that the charges  !

are satisfactory. A continual check of the firing circuit continuity 1 is provided by pilot lights in the control room. l B. Only one of two standby liquid control pumping circuits is needed for proper operation of the system. If one pumping circuit is found to be  !

inoperable, there is no immediate threat to shutdown capability, and reactor operation may continue while repairs are being made. Assurance that the remaining system will perform its intended function and that the reliability of the system is good is obtained by demonstrating operation of the pump in the operable circuit at least once daily. A reliability analysis indicates that the plant can be operated safely in this manner for 7 days.

0624H 3.4/4.4-3 Amendment No.

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QUAD-CITIES DPR-29 -

The Standby. Liquid Control System is operated by a five position control switch (SYS 1&2, SYS 1, OFF, SYS 2, and SYS 2&lb The single pump operation positions are for operating cycle surveillance testing.

This testing demonstrates the capability of firing the explosive trigger assemblies. Also during this' testing,' sodium pentaborate.is circulated from the storage tank, through one suction line. through a pump, and back into the storage tank'. This is'done separately for each system demonstrating that both suction lines.are not plugged. The two-pump operation positions will be used for the injection of the sodium pentaborate into the vessel during an ATHS event. By using the two ]

pump operation position, the Standby Liquid Control System will be. 'I meeting the requirements'of 10CFR50.62 (Requirements for reduction of risk from ATHS events for light-water-cooled nuclear ~ power plants). i l

C. The solution saturation temperature of 137. sodium pentaborate, by .]

weight, is 59'F. The solution shall be kept at least 100F above the Lj saturation temperature to guard against boron precipitation. The 10*F margin is included in Figure 3.4-2. Temperature and liquid level lq 1 l

alarms for the system are annuciated in the control room.

Pump operability is checked on a frequency to assure a high reliability ]

of operation of the system should it ever be_ required, j r Once the solution has been made up, boron concentration will not vary.

• unless more boron or more water is added. Level indication and alarm j indicate whether the solution volume has-changed,'which might indicate j a possible solution concentration change. Considering theseLfactors, ,

the test interval has been established. R i

0. Periodic tests to demonstrate two-pump flow capability are not feasible ,

in the present system configuration and are unnecessary because the j flow path integrity can be determined'from the test of a single pump.

Comparison of single-pump test pressures with previous results and correlation of these data with initial two-pump tests are used to verify the capability of the piping.

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I 0624H/0243Z 3.4/4.4-3a Amendment No. )

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. QUAD-CITIES I OPR-29 9  :

l 4875 gal g,75 fnas oeu24 G

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12 VOLUME C ENTRATION s

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VOLUME OF SOLUTION (gal)

FIGURE 3.4-1 STANDBY-LIQUID CONTROL' SOLUTION REQUIREMENTS g

ATTACHMENT 2

SUMMARY

OF CHANGES I

Ten (10)' changes to the Quad Cities Station Unit 1 Technical Specification have been identified and are listed below as follows:

1) Page 3.4/4.4-1 (a) Surveillance Requirements, Item A 1.

Change "39" to "40" f

2) Page 3.4/4.4-2 .j l

(a) Limiting Conditions for Operation, Item C Delete "that satisfies the volume-concentration requrlements of ,

Figure 3.4-1 and" and replace with "of at least 3733 gallons of at l

least 14 WT percent sodium pentaborate Decahydrate (Na2 Bo i 016 - 10 H O)"

2 (b) Surveillance Requirements A 2.

Change "1400 and 1490" to "1455 and 1545" i

l 3) Page 3.4/4.4-3 l (a) Change "90 to 120" to "83" (b) Change "3470 gallons of solution having a 13.4%" to "3,321 gallons of solution having a 14%" ,

(c) Delete "The time require.nent (90 to 120 minutes) for insertion of the boron solution....therefore, cannot be inserted.)" Replace with "For a required pumping rate of 40 gpm, 3321 gallons... meets the requirements of 10 CFR 50.62."

4) Page 3.4/4.4-3a (New Page)

(a) Add new paragraph to Item (b) Which reads as follows "The Standby l

Liquid Control System is operated by a five position control switch... meeting the requirements of 10 CFR 50.62 (Requirements for reduction of risk from ATWS events for light-water-cooled nuclear ,

power plants)." l i

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i (b) Add new Item.D which reads'as follows, " Periodic tests to.; .

s demonstrate two-pump. flow capability...are used'to verify the 'l capability of the piping. -

5) Figure 3.4-1, Standby Liquid l Control Solution Requirements Replace Figure 3.4.1 with new Figure which has been marked as ,'.' Deleted" l as a' result'of the proposed license amendment. _

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. 4 ATTACHMENT 3 EVALUATION OF SIGNIFICANT HAZARDS CONSIDERATION' )

STANDBY LIOUID CONTROL SYSTEM (SBLC)

DESCRIPTION OF AMENDMENT REQUEST Commonwealth Edison (CECO) proposes to modify the Quad Cities Unit 1 Technical Specifications to support a modification to the Standby Liquid Control System (SBLC) to meet the requirements of 10 CFR 50.62. The modification consists of providing a second pump suction line from the SBLC tank to the common suction header, codifying the SBLC tank to provide a nozzle for the suction piping and, lastly, modifying the controls to provide for running both pumps simultaneously. The specific changes to the Technical Specifications' involve replacing the boron concentration versus solution volume curve (Figure 3.4-1) with a minimum allowable volume of 3321 gallons of solution at a minimum concentration of 14 weight percent. The required SBLC pump flow rate is increased from 39 to 40 gpm. Also the allowable setpoint band for the system pressure relief valves has been increased from the current 1400 to 1490 psig to a band of 1455 to 1545 psig to reflect the increased pump discharge pressure during two pump operation. Finally, the Technical Specification bases have been revised to reflect the above changes.

10 CFR 50.62(c)(4) requires a SBLC system with a wimimum flow capacity and boron content equivalent to 86 gpm of 13 weight percent sodium pentaborate solution. For Quad Cities Unit 1, this is being accomplished by '

modifying the SBLC system to allow dual pump operation (80 gpm combined flow rate) and revising the Technical Specifications to require a 14% minimum concentration. The minimum required volume of solution in the Technical Specifications is revised from the previous 3,470 gallons of 13.4% solution '

(from Figure 3.4-1) to 3,321 gallons of 14% solution. This preserves the original amount of boron injection. As a result, of this change, Figure 3.4-1 has been marked as " Deleted" to reflect this change.

1 As a result of two pump SBLC system operation discharge pressures j will be higher. Accordingly, the allowable system pressure rolief valve setpoints have been increased by approximately 55 psig.

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BASIS FOR NO SIGNIFICANT HAZARDS DETERMINATION Commonwealth Edison has evaluated the proposed Technical Specification changes and determined they do not represent a significant hazards consideration. Based on the criteria for defining a significant hazards consideration established in 10 CFR 50.92(c), operation of Quad Cities in accordance with the proposed amendment will not:

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1) Involve a significant increase in the probability or consequences of an l accident previously evaluated because; 1 i

(a) the proposed changes maintain the total amount of boron injection k previously required by the Technical Specifications thereby maintaining the previous shutdown reactivity capability. The proposed changes are needed to implement the requirements of 10 CFR  ;

50.62 and have no impact on systems,or equipment that could poten- i tially initiate or impact the probability of an accident. Therefore, the probability or consequences of previously evaluated accidents is unchanged. j

2) Create the possibility of a new or different kind of accident from any accident previously evaluated, because; (a) the changes involve a system whose only function is to provide a backup shutdown capability. The changes do not affect any systems or '

equipment which could initiate an accident. As a result,'the proposed amendment does not create the possibility of a new or different kind of accident from any accident previously evaluated.

3) Involve a significant reduction in the margin of safety, because; (a) the overall shutdown reactivity capability (i.e. total boron injection) of the SBLC system is not reduced by these changes -The proposed amendment supports required modifications which will increase the SBLC system injection rate, thereby increasing not l

reducing, the margin of safety for Anticipated Transient without '

Scram (ATWS) events.

Based on the proceeding reassessment, Commonwealth Edison has determined that the proposed Technical Specification changes involve no Significant Hazards Considerations and request its approval in accordance with the provisions of 10 CFR 50.91(a)(4) .

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