ML20206J723

Proposed Tech Specs Pages for Proposed Change 212,modifying TS to Enhance Limiting Conditions for Operation & Surveillance Requirements Relating to SLC Sys

ML20206J723
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Site:	Vermont Yankee File:NorthStar Vermont Yankee icon.png
Issue date:	05/05/1999
From:	VERMONT YANKEE NUCLEAR POWER CORP.
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ML20206J715	List: ML20206J712 ML20206J723
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NUDOCS 9905120313
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'

VYNPC 4.4. SURVEILLANCE REQUIREMENTS 3.4 LIMITING CONDITIONS FOR _

OPERATION OL 4.4 REACTOR STANDBY LIQUID CONTROL 3.4 REACTOR STkNDBY LIQUID CONTR ~ SYSTEM SYSTEM Applicability:

Applies to the periodic testing Applies to the operating status requirement for the Reactor of the Reactor Standby Liquid Standby Liqu,d i Control System.

Control System.

Obiective:

Obiective: To verify the operability of the To assure the availability of an Standby Liquid Control System.

independent reactivity control mechanism.

Specification:

Specification: Normal Operation A.

A. Normal Operation The Standby Liquid Control Except as specified in 3.4.B System'shall be verified below, the Standby Liquid operable by:

Control System shall be o erablefdurin reactor eriods when uel is in t unless: Testing pumps and valves 1.

1. Th reactor is ir old in accordance with utdown S ecification 4.6.E. _A mum flow rate of '~

and ~ 35 gpm at 1275 psig shaJ1 be verified for each pumpf by frec neral culatied w r to

,, ,JL "3"s

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2. Verifying the continuity Control rods e fully j of the explosive charges 2 at least monthly.

inserted a Specific lon 3.3.A is met. In addition, at least once during each operating cycle, the Standby Liquid Control System shall be verified operable by:

3. Testingthatthesettingl of the pressure relief valves is between 1400 and 1490 psig.

Initiating one of the l 4.

standby liquid control loops, excluding the primer chamber and inlet fitting, and verifying that a flow path from a .

pump to the reactor 7

9905120313 990505 PDR ADOCK 05000271 j P

PDR 4 92 Amendment' No. Ma, WG,164

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VYNPS 3.4 LIMITING CONDITIONS FOR 4.4 SURVEILLANCE REQUIREMENTS OPERATION vessel is availabl p ing-dpineraliz d - -[~gf I I

w er inYo the re to

>esseld" Both loops f shall be tested over the J course of two operating  !

cycles, '

j s

4

5. Testing the new trigger l assemblies by installing j one of the assemblies in I the test block and j firing it using the I installed circuitry. /

Install the unfired assemblies, taken from j the same batch as the j fired one, into the explosion valves.

6. Recirculating the f borated solution.

B. Operation with Inoperable B. Operation with Inop eable Components Components From and after the date that When a component becomes a redundant component is inoperable, its redundant i made or found to be component shall be or shall  !

inoperable, reactor have been demonstrated to be i operation is termissible operable within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

during the succeeding seven days unless such component is sooner made operable.

C. ' Liqdd Poison Tank -Aoron] C. f Liqdd Poisd Tank -/ Boron Co6 centration / j Coricentrat(on jf At all times when the Standby Liquid Control j/' _

l System is required to be Standby Llauld Control System operable, the following Tank- Borated Solution conditions shall be met: ,_

1. The net volume versus 1.

• -~

The solution volume in

- ._; S)'-

concentration of the the tank and temperature sodium pentaborate in the tank and suction solution in the standby piping shall be checked liquid control tank at least daily.

shall meet the requirements of Figure 3.4.1.

Amendment No. 443, 4k4, 164 ,

93 4

1 VYNPS 3 . *4 LIMITING CONDITIONS FOR 4.4 SURVEILLANCE REQUIREMENTS OPERATION

2. The solution 2. Sodium pentaborate temperature, including concentration shall be that in the pump suction detenmined at least once piping, shall be a month and within maintained above the 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> following the curve shown in addition of water or Figure 3.4.2. boron, or if the solution temperature

- - drops below the limits i

specified by

[pj - d.Z'A/ 5E4 T ) Figure 3.4.2.

D. If Specification 3.4.A or B is not met, an orderly f % M.T M h -- ~' '7 ,

shutdown shall be initiated and the reactor shall be in I

)

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 />.

l j

E. If Specification 3.4.C is not met, action shall be l i

immedjately initiated to correct the deficiency. If l at the end of 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> the l system has not been restored '

to full operability, then a shutdown shall be initiated with the reactor in cold j shutdown within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of 8 initial discovery.

I knendment No ' 45, 44, 102 94

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VYNPS

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]

BASES: '

l l

3.4 & 4.4 REACTOR STANDBY LIOUID CONTROL SYSTEN A. Normal Operation The design objective of the Reactor Standby Li id Control System is  !

to provide the capability of bringing the reacto from full power to  ;

a cold, xenon-free shutdown assuming that none of e withdrawn l control rods can be inserted. To meet this objecti the Liquid l Control System is designed co inject a quantity of boro ich i produces a concentration of 800 ppm of boron in the reactor core in l 1ess than 138 minutes. An 800 ppe or concentration in the reactor j core is required to bring the reacht f om full power to a St ok j subcritical condition. An additioral rgin (25% of boron) is added j for possible imperfect mixing of th ch ical solution in the reactor water. A minimum quantity of 3850 allo s of solution having a 10.1%

sodium pentaborate concentration is requ red to meet this shutdown

[ requirement. ( _ _ _ _

The time requirement (138 minutes) for insertion of the boron solution was selected to override the rate of reactivity insertion due to cooldown of the reactor following the x .r ooison peak. For ,

a required minimum pumping rate of 35 gallons per minute, the maximum  !

not storage volume of the boron solution is established as -l 4830 gallons. p y gg)-- - -

---(/ 0J Boron concentration, solution temperature, and volume are checked Don r Il a f requency to assure a high reliability of operation of the system f"*l)'.J should it ever by required A operability testing n accordance 1 with spectrication 4.0.t; as adequate to detect if fa ures have l occurred. Flow, relief valve, circuitry, and trigg assembly I testing at the prescribed intervals assures a hig reliability of j system operation capability. Recirculation of a borated solution '

is done during each operating cycle to ensure e suction line from the boron tank is clear. (ra>sstr)s dm e J _. ,o- = . L' .4 B. Operation With Inoperable Components '~~'-  %

sk 4 m L Hs A) '

1

~3,j 1 Only one of the 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 system will perform its intended function is obtained from the results of the pump and valve testing performed in accordance with ASME section XI requirements. Whenevet one redundant component is inoperable, the potential for extended operation with two subsystems inoperable is reduced by requiring that the redundant component be tested within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

"':n' --"' ~~~* ~~* ~~~

C. i = i d "r i n "cr ; C n c r t r:t i c .p --*

The solution saturation temperature varies with the concentration of sodium pentaborate. The solution shall be kept at least 10*F above the saturation temperature to guard aoainst boron precipitation. The 10*F margin is included in FigurO.0.2 ;f th: ? "". Temperature and liquid level alarms for the system are a@unciated in the control Room.

• • • ~

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Amendment No. H g, 4 H , 128 97

- _ . - - - . . . . .I..... . .. . . .. . . ..

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VYNPS' l BASES: S.4 & 4.4 (Cont'd)

Once the solution has been made up,-boron concentration will not vary unless more boron or more water is added. Level indication and alarm indicate whether the solution volume has changed which might indicate-a possible solution concentration change. Considering these factors, the test interval has been established.

Sodium pentaborate concentration is determined within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> following the addition of water or boron, or if the solution J temperature drops below specified limits. The 24-hour limit allows for 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> of mixing, subsequent testing, and notification of shif .

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Amendment No. 4M, 128 98'

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VituuGNT YANNu; Nrcu:in POwsn COnPOnAUON

- Docket No. 50-271 BVY 99-69 Attachment 4-Vermont Yankee Nuclear Power Station Proposed Technical Specification Change No. 212 ATWS Rule (10CFR50.62)- Standby Liquid Control System  :!

l Retyped Technical Specification Pages -

l i

a

Vennost YAsn.n Nt cixAn Powen Conroariios .

BVY 99-69 / Attachment 4 / Page'1 Listine of Affected Technical Specifications Panes Replace the Vermont Yankee Nuclear Power Station Technical Specifications pages listed below with the revised pages. The revised pages contain vertical lines in the margin indicating the areas of change.

Remove Insert 92 92' 93 93 94 94 97 97 98 98 I

J J

1

UYNPC 3.4 LIMITING CONDITIONS FOR 4.4 SURVEILLANCE REQUIREMENTS OPERATION  ;

3.4 . REACTOR STANDBY LIQC1 :ONTROL 4.4 REACTOR' STANDBY LIQUID CONTROL SYSTEM SYSTEM Applicability: Applicability:

Applies to the operating status Applies to the periodic t'esting of the Reactor Standby Liquid . requirement for the Reactor Control System. . Standby Liquid Control System.  ;

Objective: Objective:

To assure the availability of an- To verify-the operability'of the independent reactivity control Standby Liquid Control System.

mechanism.

Specification: Specification:

A. Normal Operation A. Normal Operation Except as specified in 3.4.B The Standby Liquid Control below, the Standby Liquid System shall be verified Control System shall be operable by:

operable when the reactor mode switch is in either the .l. Testing pumps and valves "Startup/ Hot Standby" or in accordance with "Run" position, except to Specification 4.6.E. A allow testing of minimum flow rate of instrumentation associated 35 gpm at 1275 psig with the reactor mode switch shall be verified for interlock functions each pump. l provided:

2. Verifying the continuity

1. Reactor coolant of the explosive charges temperature is less than at least monthly, or equal to 212* F; In addition, at least once

2. All control rods remain during each operating cycle, fully inserted in core the Standby Liquid Control cells containing one or System shall be verified more fuel assemblies; operable by:

and

3. Testing that the setting

3. No core alterations are of the pressure relief in progress. valves is between 1400 and 1490 psig.

4. Initiating one of the-standby liquid control loops, excluding the primer chamber and inlet fitting, and verifying that a flow path from a pump to the reactor vessel is.available.

Both loops shall.be tested over the course of,two operating cycles.

' Amendment; No. l .MG, Me, M4 92

5 VYNPS

' 3.4 LIMITING CONDITIONS FOR. 4.4 SURVEILLAFCE REQUIPEMENTS ]

OPERATION' )

5. Testing the new trigger assemblies.by installing ,

one of the assemblies in j the test block and firing it using the installed circuitry.

Install the unfired-assemblies, taken from the same batch as the

. fired one, into the explosion valves. (

6. Recirculating the borated solution. .;

B. Operation with Inoperable B. Operation with Inoperable Components Components From and after the date that When a component becomes a redundant component is inoperable, its redundant made or found to be component shall be or shall inoperable, reactor have been demonstrated to be operation is permissible operable within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

during the succeeding seven days unless such component is sooner made operable.

C. Standby Liquid Control System C. Standby Liquid Control System Tank - Borated Solution Tank - Borated Solution 1

At all times when the Standby Liquid Control ,

System is required to be I operable, the following l conditions shall be met:

1. The net volume versus 1. The solution volume in concentration of the the tank and temperature sodium pentaborate in the tank and suction solution in the standby piping shall be checked i liquid control tank at least daily.

shall meet the requirements of Figure 3.4.1.

. Amendment No. 443, 444, 444 93

VYNPS 3.4 LIMITING CONDITIONS FOR 4.4 SURVEILLANCE REQUIREMENTS OPERATION

2. The solution 2. Sodium pentaborate temperature, including concentration shall be that in the pump suction determined at least once piping, shall be a month and within maintained above the 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> following the curve shown in addition of water or Figure 3.4.2. boron, or if the solution temperature

3. The combination of drops below the limits Standby Liquid Control specified by System pump flow rate, Figure 3.4.2.

boron concentration, and boron enrichment shall satisfy the following 3. The baron-10 enrichment relationship for the of the borated' solution Standby Liquid Control required by Specification System to be considered 3.4.C.3 shall be tested operable: and verified once per operating cycle.

O M251 C E

- x - x - x - 21 86 M 13 19.0 where:

C= the concentration of )

sodium pentaborate i solution (weight j percent) in the Standby Liquid Control System tank E= the boron-10 l enrichment (atom I percent) of the .

sodium pentaborate l solution Q= 35 gpn M251

-- = a constant (the M ratio of mass of water in the reference plant compared to VY)

D. If Specification 3.4.A or B is not met, an orderly shutdown shall be initiated and the reactor shall be in 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 />.

E. If Specification 3.4.C is not met, action shall be immediately initiated to correct.the deficiency. If at the end of 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> the system has not been restored to full operability, then a shutdown shall be initiated with the reactor in cold shutdown within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of initial discovery.

Amendment No M, M, M3 94

r-VYNPS BASES:

3.4 & 4.4 REACTOR STANDBY LIQUID CONTROL SYSTEM A. Normal Operation The design objective of the Reactor Standby Liquid 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 i '

rods can be inserted. To meet this objective, the Standby Liquid l Control System is designed to inject a quantity of boron which produces a concentration of 800 ppm of natural boron in the reactor core in less than 138 minutes. An 800 ppm natural boron concentration in the-reactor core is required to bring the reactor from full power to a 5%

Ak subcritical condition. An additional margin (25% of boron) is added for possible imperfect mixing of the chemical solution in the reactor water. A minimum quantity of 3850 gallons of solution having a 10.1%

natural sodium pentaborate concentration is required to meet this l shutdown requirement.

The time requirement (138 minutes) for insertion of the boron solution  !

was selected to override the rate of reactivity insertion due to cooldown of the reactor following the xenon poison peak. For a l

q required minimum pumping rate of 35 gallons per minute, the maximum net storage volume of the boron solution is established as 4830 gallons.

In addition to its original design basis, the Standby Liquid Control System also satisfies the requirements of 10CFR50.62(c) (4) on anticipated transients without scram (ATWS) by using enriched boron.

The ATWS rule adds hot shutdown and neutron absorber (i.e., boron-10) injection rate requirements that exceed the original Standby Liquid Control System design basis. However, changes to the Standby Liquid i Control System as a result of the ATWS rule have not invalidated the l original design basis.

With the reactor mode switch in the "Run" or "Startup/ Hot Standby" position, shutdown capability is required. With the mode switch in

" Shutdown," control rods are not able to be withdrawn since a control ,

rod block is applied. This provides adequate controls to ensure that '

the reactor remains subcritical. With the mode switch in " Refuel,"

only a single control rod can be withdrawn from a core cell containing fuel assemblies. Determination of adequate shutdown margin by Specification 3.3.A ensures that the reactor will not become critical.

Therefore, the Standby Liquid Control System is not required to be operable when only a single control rod can be withdrawn.

Pump operability testing (by recirculating domineralized water to the l test tank)in accordance with Specification 4.6.E is adequate to detect if failures have occurred. Flow, relief valve, circuitry, and trigger assembly testing at the prescribed intervals assures a high reliability of system operation capability. Recirculation of the borated solution is done during each operating cycle to ensure one suction line from the boron tank is clear. In addition, at least once during each operating cycle, one of the standby liquid control loops will be initiated to verify that a flow path from a pump to the reactor vessel is available by pumping demineralized water into the reactor vessel.

B. Operation With Inoperable Components Only one of the two standby liquid control pumping circuits is needed for proper operation of the system. If one pumping circuit is found to Amendment No. M3, 444, 4M 97

VYNPS.

, be, inoperable, there is no immediate threat to shutdown capability, and-reactor. operation may continue while repairs.are being made. Assurance that the system will perform its intended function is obtained from the-results of the pump and valve. testing performed in accordance with ASME Section XI requirements. Whenever one redundant component is inoperable, the potential for extended' operation with two subsystems inoperable is reduced by requiring that the redundant component is tested within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

C. Standby Liquid Control System Tank - Borated Solution The solution saturation temperature varies with the concentration of sodium pentaborate. The solution shall be kept at least 10*F above the saturation temperature to guard against boron precipitation. The 10'F margin is included in Figure 3.4.2. Temperature and liquid level- l-alarms for the system are annunciated in the Control Room.

~

Once the solution has been made up, boron concentration will not vary unless more boron or water is added. Level indication and alarm indicate whether the solution volume has changed which might indicate a possible solution concentration change. Considering these factors, the test interval has been established.

Sodium pentaborate concentration is determined within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> following the addition of water or boron, or if the solution temperature drops below specified limits. The 24-hour limit allows for 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> of mixing, subsequent testing, and notification of shift personnel. l 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. Isotopic tests of the sodium pentaborate are performed periodically to ensure that the proper boron-10 atom percentage is being used.

10CFR50.62(c) (4) requires a Standby Liquid Control System with a minimum flow capacity and boron content equivalent to 86 gpm of 13 weight percent natural sodium pentaborate solution in the 251-inch reactor pressure vessel reference plant. Natural sodium pentaborate solution is 19.8 atom percent boron-10. The relationship expressed in Specification 3.4.C.3 also contains the ratio M251/M to account for the difference in water volume between the reference plant and Vermont Yankee. (This ratio of masses is 628,300 lbs./401,247 lbs.)

To comply with the ATWS rule, the combination of three Standby Liquid Control System parameters must be considered: boron concentration, Standby Liquid Control System pump flow rate, and boron-10 enrichment.

Fixing the pump flow rate in Specification 3.4.C.3 at the minimum flow rate of 35 gpm conservatively establishes a system parameter that can be used in satisfying the ATWS requirement, as well as the original system design basis. If the product of the expression in Specification 3.4.C.3 is equal to or greater than unity, the Standby Liquid Control System satisfies the requirements of 10CFR50.62(c) (4) .

' Amendment No. M 3, 424 98