Text

Proposed Tech Specs Re High Head Safety Injection Flow Balancing
	ML20059K141
Person / Time
Site:	North Anna
Issue date:	11/10/1993
From:	; VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	;
Shared Package
ML20059K134	List: ML20059K127; ML20059K141;
References
	NUDOCS 9311150197
	Download: ML20059K141 (6)
	v • d • e

._ .. .. _ _

t :

i i

i I

i 1

- Attachment 3 - '

l Technical Specifications Changes i

F

]

l l

6 l

l l

l 1

l I

1 l

9311150197 931110 E! !

. PDR ADOCK 05000338 8

P i t PDR .Ua.

susRcecycmscocxmssru !

SURVEILLANCE REQUIREMENTS (Continued) i

2. Verifying that each of the following pumps start automatically upon receipt of a - l safety injection test signal: -

l a) Centrifugal charging pump,-and b) Low head safety injection pump. !

I

f. By verifying that each of the following pumps develops the-indicated discharge .i pressure (after subtracting ' suction pressure) on recirculation flow when tested l pursuant to Specification 4.0.5. t, i

1. Centrifugal charging pump 2 2410 psig.

1

2. Low head safety injection pump 2156 psig.

l

\

g. By verifying that the following manual valves requiring adjustment to prevent pump l

" runout" and subsequent component damage are locked and tagged in the proper i' position for injection:

l

1. Within 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months following completion of any repositioning or maintenance on the !

valve when ECCS systems are required to be OPERABLE. '

i

2. At least once per 18 months. !

1. 1-SI-188 Loop A Cold Leg

2. 1-SI 191 Loop B Cold Leg k

3. 1-SI-193 LoopC Cold Leg

4. 1-SI-203 Loop A Hot Leg

5. 1-SI-204 Loop B Hot Leg l'

6. 1-SI-205 Loop C Hot Leg

i

h. By performing a flow balance test, during shutdown, following -completion of !

modifications to the ECCS subsystems that alter the subsystem flow characteristics !

and verifying that:

, 1. For high head safety injection lines, with a single pump runmng:

e a) The sum of the injection line flow rates, excluding the highest flow rate, is !

2 359 gpm, and !

t b) The total pump flow rate is s 660 gpm. i NORTH ANNA - UNIT 1 3/4 5-5 Amendment No. ;

i i

I

r .

b 3 EMERGENCYCORE CODUN3 SYSTEM SURVEILLANCE REQUIREMENTS (Continued)

f. By verifying that each of the following pumps develop the indicated discharge !

pressure (after subtracting suction pressure) on recirculation flow when tested l pursuant to Specification 4.0.5.

i

1. Centrifugal charging oump greater than or equal to 2410 psig. t

2. Low head safety injection pump greater than or equal to 156 psig. [

g. By verifying that the following manual valves requiring adjustment to prevent pump ' i

runout" and subsequent component damage are locked and tagged in the proper pos!! ion for injection:

1. Within 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months following completion of any repositioning or maintenance on the valve when the ECCS systems are required to be OPERABLE.

2. At least once per 18 months. 1

1. 2-SI-89 Loop A Coldleg

2. 2-SI-97 Loop B Cold Leg '

3. 2-SI-103 Loop C Cold Leg

4. 2-SI-116 Loop A Hot Leg

5. 2-SI-111 Loop B Hot Leg

6. 2-SI-123 Loop C Hot Leg

h. By performing a flow balance test, during shutdown, following completion of modifications to the ECCS subsystems that alter the subsystem flow characteristics t

and verifying that:

1. For high head safety injection lines, with a single pump running:

a) The sum of the injection line flow rates, excluding the highest flow rate, is 2 359 gpm, and '

b) The total pump flow rate is s 660 gpm.

i I

i NORTH ANNA - UNIT 2 3/4 55 Amendment No. l i

i i

- - . , , , , , , , ..,-., . ~,.,v,..

r Attachment 4 Significant Hazards Consideration l

t i

SIGNIFICANT HAZARDS CONSIDERATION North Anna Unit 1 and 2 Technical Specification 4.5.2.h.1 specifies surveillance :

requirements for the flow balancing of the high head safety injection lines. Achieving an acceptable flow balance assures that adequate core cooling and negative reactivity is ,

provided to mitigate the consequences of design basis accident.( ltem a) under this ,

surveillance requirement specifies that the sum of the injection iine flow mies, excluding the highest flow rate is > 359 gpm with a single pump running. Item b) under this i

surveillance requirement specifies that the total charging /high head safety injection >

(HHSI) pump flow rate with a single pump running is s 660 gpm. Item c) under this surveillance requirement specifies that a value of 2 48.3 gpm be used to simulate reactor '

coolant pump seal injection flow during cold leg injection balancing.

The requirement to specify a simulated seal injection flow rate was added August 4, 1993 by License Amendment Nos.171 and 151 for Units 1 and 2 respectively. This requirement has been determined to be unnecessary and has, in practice, inhibited our ability to meet the minimum and maximum flow rate specifications. These proposed .

Technic,al Specification changes would allow the elimination of the simulated reactor !

coolant pump seal iniection flow requirement in Technical Specification 4.5.2.h.1.c and make minor editorial changes to Technical Specifications 4.5.2.h.1.a and b to improve the readability.

l At 09:30 hours and again at 14:45 hours on November 8,1993, North Anna Unit 2 :

entered an action statement to be in hot standby within six hours as required by '

Technical Specification 3.0.3. It had been determined that Technical Specification 3.5.2, which requires two operable HHSI pumps, could not be met. The HHSI pumps were determined to be inoperable because the total pump flow rate required by Technical Specification 4.5.2.h.1.b may not have been met. In addition, the limitation on seal injection flow specified by Technical Specification 4.5.2.h.1.c contributed to this.

determination. On the same day, this condition was discussed with the NRC.

Enforcement discretion was requested for 1) a 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months period to readjust the seal ;

injection flows to the reactor coolant pumps in order to meet the total pump flow rate in :

Technical Specification 4.5.2.h.1.b of s 660 gpm, and 2) to eliminate the simulated :

reactor coolant pump seal injection flow requirement of Technical Specification 4.5.2.h.1.c of 2 48.3 gpm. The requested enforcement discretion was verbally approved i by Mr. G. C. Lainas of the NRC on November 8,1993. Virginia Electric and Power Company letter dated November 9,1993 (Serial No.93-727) documented the requested enforcement discretion and committed to promptly submitting an Emergency Technical Srecification change request.

The need for enforcement discretion, and consequently the proposed Technical Specification changes, is due in part to an unintended consequence of a previous license amendment issued on August 4,1993 involving Technical. Specification 4.5.2.h.1. That license amendment added, as item c, a specific range of calculated values for seal injection flow to be used during the actual flow balancing process. Prior to this amendment, the specific flowrate had not appeared in the Technical l Specifications. It was believed that by specifying the value in the Technical j Specifications, a more complete picture of the flow balance process would be provided l

in the document. The primary purpose of seal injection flow is to provide the required minimum seal flows specified by the reactor coolant pump vendor. These flows are adjustable and may be changed due to plant operations and pump seal conditions.

When the Reactor Coolant System (RCS) is depressurized during the design basis accident, the differential pressure between the safety injection flow header and the RCS increases and causes the seal injection flow to increase. The accident analysis takes no credit for this flow, and it is presumed to be lost. By meeting Technical Specifications 4.5.2.h.1.a and b, the limits of safety analysis are met with margin. The requirement to specify a simulated seal injection flow rate has, in practice, inhibited our ability to meet the minimum and maximum flow rate , specifications. The proposed Technical Specification changes do not affect the ability of the HHSI system to perform its intended safety function.

Virginia Electric and Power Company has reviewed the proposed Technical Specification changes against the criteria of 10 CFR 50.92 and has concluded that the changes as propos.ed do not pose a significant hazards consideration. Specifically, operation of North Anna Power Station in accordance with the proposed Technical Specification changes will not:

1. Involve a significant increase in the probability or consequences of an accident previously evaluated. The proposed Technical Specification changes continue to require that with one HHSI pump running, the sum of the flows through the two lowest flow branch lines shall be 2 359 gpm and the total HHSI pump flow rate shall be s 660 gpm. These requirements ensure the correct flow balance alignment and flow rates required to meet the safety analysis.

Likewise, the consequences of the accidents previously evaluated will not

crease as a result of the proposed Technical Specification changes. The ystem performance will remain bounded by the existing safety analysis for all postulated accident conditions.

2. Create the possibility of a new or different kind of accident from any accident previously evaluated. The proposed Technical Specification changes will not ,

affect the capability of the HHSI System to perform its design function. The proposed Technical Specification changes are bounded by the existing safety analysis and does not involve operation of plant equipment in a different manner from which it was designed to operate. Since a new failure mode is not created, a new or different type of accident is not created.

3. Involve a significant reduction in a margin of safety. The system performance ,

will remain bounded by the existing safety analysis at the specified flow rates, l therefore, safety margins are not reduced.

Virginia Electric and Power Company concludes that the activities associated with these proposed Technical Specification changes satisfy the no significant hazards

consideration criteria of 10 CFR 50.92 and, accordingly, a no significant hazards l consideration finding is justified.

A

ML20059K141

Text

Navigation menu

Search