ML20195C884

Proposed Tech Specs Clarifying Suppression Chamber Water Temp SR 4.7.A, Primary Containment & Modifying Associated TS Bases

ML20195C884
Person / Time
Site:	Vermont Yankee
Issue date:	05/26/1999
From:	VERMONT YANKEE NUCLEAR POWER CORP.
To:
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ML20195C876	List: ML20195C871 ML20195C884
References
NUDOCS 9906090016
Download: ML20195C884 (8)

Text

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Docket No. 50-271 BW 99-75 Attachment 3 Vermont Yankee Nuclear Power Station Proposed Technical Specifier On Change No. 203 Suppression Pool Water Temperature Surveillance 4 Marked-up Version of the Current Technical Soecifications 9906090016 990526 'T PDR ADOCK 05000271; P PDR_;

p. ,

VYNPS  ;

l l

3.7 LIMITING CONDITIONS FOR 4.7 SURVEILLANCE REQUIREMENTS OPERATION 3.7 STATION CONTAINMENT SYSTEMS 4.7 STATION CONTAINMENT SYSTEMS l Applicability: Applicability:

Applies to the operating status Applies.to the primary and of the primary and secondary secondary containment system containment systems. integrity.

Obiective: Obiective:

To assure the integrity of the To verify the integrity of the primary and secondary primary and secondary containment systems. containments.

l Specification: Specification:

A. Primary Containment A. Primary containment

\/trif d Hy N

1. 0Thesuppfess*ionchamber

1. Whenever primary containment is required, water level a_nd Merge.

the volume and temperaturejsf.aly be-temperature of the water 6hteks(d Wnce/pe:/ sh t *[:h in the suppression chamber shall be p.,,,.Avisualinspectionof the suppression chamber app \:c.c bte.

U n:h ,

maintained within the interior including water following limits: line regions and the interior painted

a. Maximum Water surfaces above the water Temperature during line shall be made at normal operation - each refueling outage.

90*F. p A /Wh ne r ner is D l \/v:fy

b. Maximum Water

[ ialdi tio nerao on relhic of sof Temperature during "

any test operation ad s h at a pr ssi t

po 1, .e R**^fet IA 5<

which adds heat to col em rat re al #Wble.

.+ke app the suppression e ont ual .m it red pool - 100*F; an al ob rv a' lim #

however, it shall 1 gge eve 5 n es not remain above nti the ea ad tie J6C^4*^ h.4^')

t 90'T for more than Lis ermi atedJ Wheneifer +tsM y j adM 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. 7 w. there is indication of relief valve operation to

c. If Torus Water . with the temperature of Nf(* *pio^

Temperature exceeds the suppression pool PO 110'F, initiate an reaching 160*F or more immediate scram of and the primary coolant the reactor. Power system pressure greater operation shall not than 200 psig, an 4 be resumed until external visual )

the pool examination of the i temperature is suppression chamber l reduced below 90'F. shall be conducted )

l before resuming power ]

d. During reactor . operation. l i isolation '

I

! conditions, the s

reactor pressure vessel shall be depressurized to less than 200 psig Amendment No. M, M, g ,163 146

VYNPS 38EEE: 3.7 (Cont'd) l The Standby Gas Treatment System (SGTS) is designed to filter and exhaust the Reactor Building atmosphere to the stack during secondary containment isolation conditions, with a minimum release of radioactive materials from the Reactor Building to the environs. To insure that the standby gas treatment system will be effective in removing radioactive contaminates from the Reactor Building air, the system is tested periodically to meet the intent of ANSI N510-1975.

Both standby gas treatment fans are designed to automatically start upon containment isolation and to maintain the Reactor Building pressure to approximately a negative 0.15 inch water gauge pressure; all leakage should be in-leakage. Should the fan fail to start, the redundant alternate fan and filter system is designed to start automatically. Each of the two fans has 100% capacity. This substantiates the availability of the operable circuit and results in no added risk; thus, reactor operation or refueling operation can continue. If neither circuit is operable, the plant is brought to a condition where the system is not required.

When the reactor is in cold shutdown or refueling the drywell may be open and the Reactor Building becomes the only containment system.

During cold shutdown the probability and consequences of a DBA LoCA are subatantially reduced dus.to the pressure and temperature limitations in this mode. However, for other situations under which i significant radioactive release can be postulated, such as during operations with a potential for draining the reactor vessel, during core alterations, or during movement of irradiated fuel in the j secondary containment, operability of standby gas treatment is required. An alternate electrical power source for the purposes of Specification 3.7.3.1.b shall consist of either an Emergency Diesel Generator (EDG) or the Vernca Hydro tie line. Maintaining availability of the Vernon Hydro tie line as an alternative to one of the EDCs in this condition provides assurance that standby gas treatment can, if required, be operated without placing undue constraints on EDG maintenance availability. Inoperability of both circuits of the SGTS or both EDGs during refueling operations requires suspension of activities that represent a potential for releasing radioactive material to the secondary containment, thus placing the plant in a condition that minimizes risk.

Use of the SGTS, without the fan and the 9 kW heater in operation, as a-vent path during torus venting does not impact subsequent adsorber capability because of the very low flows and because humidity control is maintained by the standby 1 kW heaters, therefore operation in this manner does not accrue as operating time.

D. Primary Containment Isolation Valves Double isolation valves are provided on lines that penetrate the primary containment and communicate directly with the reactor vessel and on lines that penetrate the primary containment and cammunicate with the primary containment free space. Closure of one of the valves in each line would be sufficient to maintain the integrity of l the pressure suppression system. Automatic initiation is required to '

minimize the potential leakage paths from the containment in the  !

event of a loss-of-coolant accident. l 4.7 STATION CONTAINMENT SYSTEMS T A. Primary Containment System }

Neny$

he ater n the uppress on c er is sed on for c ling i th 6 ev t of n acci ent, i. ., it s not u ed for ormal erati  ;

49 43 refor , a we kly che k of t e tempe ature d vol is a qua t

(* assu e that adequat heat emoval apabili.y is p esent.

166 Amendment No. M , 49, 143

r VYNPS 4.7 hnth BASES:

The interiors of the drywell and suppression chamber are painted to prevent rusting. The inspection of the paint during each major j refueling outage, F&ppf ox$datWly Ang6 pef yegr3 assures the paint is intact. Experience with this type of paint at fossil fueled generating ,

stations indicates that the inspection interval is adequate. }

icVel j Because of t arge volume and thermal capacity of the suppression pool, the and. temperature normally changes very slowly and monitoring these parameters daily is sufficient to establish any temperature trends.J re trin the uppre ion c1 mper ture y c ntin 11y onit reu d fr ent y log d du ng rio .of 41 ific t h at a itio , th temp ature rend wil be ose t fo lowe so at _

nroo late etio can b take f The requirement for

1. en external visual examination following any event where potentially f high loadings could occur provides assurance that no significant damage

/ was encountered. Particular attention should be focused on structural discontinuities in the vicinity of the relief valve discharge since f

these are expected to be the points of highest stress. Visual inspection of the suppression chamber including water line regions each refueling outage is adequate to detect any changes in the suppression chamber structures.

ME cLVernj e Yemperbbft. 'e h clzbeceiwed by 4=.D3 an at

• M c Mc. cWevwje. op OPEGLABL E. soppre5 don ped ha &

WGN M^

Mperah.)(t ch no ne.\s. %e d g;\$ fre p enc 3 ShC do , D45ed c6 o pscod4A3 e.v pectence. , % be accepbIolt.

M c f f e p e n e.I C .b Gr s. .fo rthev' % A4"fle d in View of

- 04her inch ca.4I'on b o,Vo ;\ c.\olc 14 +ka C o v h a>lan 9 o ov4 3 a\ec4 o pecc ters to abnerml A c.\w. din 3 al 4v m 5 3

+o CondMo A.

M CA hto.k Ib \0ein3 added 4 4g, soppfeggen poog m o g+oc by h sM a33 heav ec, ;+ is n,,c 3,s ,c3  %

vwev-c. Fre. p ta+1u.

suppre ssion poe\ hvn pe.cx4vre.

&e fcc.p encu dwc:m h s&.n3 is

%e 5' n.i: c:h- " hic.h +e d 5

• h *"

jo sMfi e d by -Vhe e d e.

This he been 3houn += be, vp +he sopp<tsstoo pect.

e.v.p=.ct eoce. , awc) a ccep&=ic>\e base.A em ope.cce n3 pool og h swro %c e. 4hek a M ow c \o\ c.

P rov E ck2 5 ar C. n o4- e.Y. cee d c cI .

M m p ev m,,,h, a rt .h

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Amendment No. 444, 164 166a

vnuuosi nsun Nrci.n.uwowi:n coiu na.uios Docket No. 50-271 BW 99-75 Attachment 4 Vermont Yankee Nuclear Power Station Proposed Technical Specification Change No. 203 i

Suppression Pool Water Temperature Surveillance Retvoed Technical Specification Paaes

F l

VYNPS i 3.7 LIMITING CONDITIONS FOR 4.7 SURVEILLANCE REQUIREMENTS OPERATION 3.7 STATION CONTAINMENT SYSTEMS 4.7 STATION CONTAINMENT SYSTEMS Applicability: Applicability:

Applies to the operating status Applies to the primary and of the primary and secondary secondary containment system containment systems. integrity.

Objective: Objective:

To assure the integrity of the To verify the integrity of the primary and secondary containment primary and secondary systems. containments.

Specification: Specification:

A. Primary Containment A. Primary Containment

1. Whenever primary 1. Verify daily that the l containment is required, suppression chamber water the volume and level and average temperature of the water temperature are within in the suppression applicable limits.

chamber shall be maintained within the A visual inspection of following limits: the suppression chamber interior including water

a. Maximum Water line regions and the Temperature during interior painted surfaces normal operation - above the water line 90*F. shall be made at each ,

refueling outage.

b. Maximum Water Temperature during Verify suppression pool any test operation average temperature is which adds heat to within the applicable the suppression pool limits every 5 minutes

- 100*F; however, it when performing testing shall not remain that adds heat to the above 90*F for more suppression pool.

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

Whenever there is

c. If Torus Water indication of relief Temperature exceeds valve operation with the 110*F, initiate an temperature of the immediate scram of suppression pool reaching I the reactor. Power 160*F or more and the operation shall not primary coolant system {

be resumed until the pressure greater than j pool temperature is 200 psig, an external A reduced below 90'F. visual examination of the l suppression chamber shall

d. During reactor be conducted before t isolation resuming power operation. j conditions, the  !

reactor pressure vessel shall be depressurized to less than 200 psig 1

Amendment No. 44, 60, GB, 463 146 l

a l

c VYMPS BASES: 3.7 (Cont'd)

The Standby Gas Treatment System (SGTS) is designed to filter and exhaust the Reactor Building atmosphere to the stack during secondary

. containment isolation conditions, with a minimum release of radioactive materials from the Reactor Building to the environs. To insure that the standby gas treatment system will be effective in removing radioactive contaminates from the Reactor Building air, the system is tested periodically to meet the intent of ANSI N510-1975. Both standby gas treatment fans are designed to automatically start upon containment isolation and to maintain the Reactor Building pressure to approximately a negative 0.15 inch water gauge pressure; all leakage should be in-leakage. Should the fan fail to start, the redundant alternate fan and filter system is designed to start automatically.

Each of the two fans has 100% capacity. This substantiates the availability of the operable circuit and results in no added risk; thus, reactor operation or refueling operation can continue. If neither circuit is operable, the plant is brought to a condition where the system is not required.

When the reactor is in cold shutdown or refueling the drywell may be open and the Reactor Buildino becomes the only containment system.

During cold shutdown the probability and consequences of a DBA LOCA are substantially reduced due to the pressure and temperature limitations in this mode. However, for other situations under which significant L radioactive release can be postulated, such as during operations with a  !

potential for draining the reactor vessel, during core alterations, or during movement of irradiated fuel in the secondary containment, f operability of standby gas treatment is required. An alternate electrical power source for the purposes of Specification 3.7.B.1.b shall consist of either an Emergency Diesel Generator (EDG) or the Vernon Hydro tie line. Maintaining availability of the Vernon Hydro tie line as an alternative to one of the EDGs in this condition provides assurance that standby gas treatment can, if required, be operated without placing undue constraints on EDG maintenance availability. Inoperability of both circuits of the SGTS or both EDGs during refueling operations requires suspension of activities that represent a potential for releasing radioactive material to the secondary containment, thus placing the plant in a condition that  ;

minimizes risk.

Use of the SGTS, without the fan and the 9 kW heater in operation, as a vent path during torus venting does not impact subsequent adsorber capability because of the very low flows and because humidity control is maintained by the standby 1 kW heaters, therefore operation in this manner does not accrue as operating time.

D. Primary Containment Isolation Valves Double isolation valves are provided on lines that penetrate the primary containment and communicate directly with the reactor vessel and on lines that penetrate the primary containment and communicate with the primary containment free space. Closure of one of the valves in each line would be sufficient to maintain the integrity of the pressure suppression system. Automatic initiation is required to minimize the potential leakage paths from the containment in the event of a loss-of-coolant accident.

1 l

Amendment No. 44, 49, 444 166

. VYNPS 4.7 STATION CONTAINMENT SYSTEMS A. Primary Containment System Th'e interiors of the drywell and suppression chamber are painted to prevent rusting. The inspection of the paint during each major refueling outage assures the paint is intact. Experience with this type of paint at fossil fueled generating stations indicates that the inspection interval is adequate.

Because of the large volume and thermal capacity of the suppression pool, the level and temperature normally changes very slowly and l monitoring these parameters daily is sufficient to establish any temperature trends.

l The average temperature is determined by taking an arithmetic average of OPERABLE suppression pool water temperature channels. The daily frequency has been shown, based on operating experience, to be acceptable. .The frequencies are further justified in view of other indications available in the Control Room, including alarms, to alert operators to an abnormal condition.

When heat is being added to the suppression pool by testing, however, j it is necessary to monitor suppression pool temperature more frequently. The 5 minute frequency during testing is justified by the rate at which tests will heat up the suppression pool. This has been shown to be acceptable based on operating experience, and provides ]

assurance that allowable pool temperatures are not exceeded.

The requirement for an external visual examination following any event where potentially high loadings could occur provides assurance that no ,

significant damage was encountered. Particular attention should be j focused on structural discontinuities in the vicinity of the relief valve discharge since these are expected to be the points of highest stress. Visual inspection of the suppression chamber including water line regions each refueling outage is adequate to detect any changes in ,

the suppression chamber structures.

1 I

Amendment No. 443, 444 166a t_