ML20024G678

Proposed Tech Specs Specifying New Temp Limitations for Suppression Pool

ML20024G678
Person / Time
Site:	Monticello
Issue date:	03/24/1975
From:	NORTHERN STATES POWER CO.
To:
Shared Package
ML20024G299	List: ML20024G298 ML20024G420 ML20024G678
References
NUDOCS 9104230502
Download: ML20024G678 (8)

Text

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DGIIBIT B j Exhibit 3 attached, consists of newly prepared pages of Appendix A Technical Specifications as listed below. 'Ibese pages incorporate the proposed chages contained in Exhibit A.

Pageo ,

i 139 140 140A (New Page) 157 157A (New Pa6e) lol I

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1 9104230502 750324 3 PDR ADOCK 050 P

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i 3.0 LIMITIIIG CONT 1ITICIC FOR OPERATION f4.0 SURVEIIlR!CE REQUIREFEIES 3.7 COIRAIIBEIE SYSTEC h.7 COIEAIIBIE!E SYSTEFG Applicability: Applicability:

w 1 Applies to the operating status of the primary applies to the primary and secondary and secondary contminment systems. containment integrity.

Objective: Otjective:

To assure the intenrity of the primary and Te verify the integrity of the primary arf 1 secondary contain& nt syntenc. secondary containment. .

Specification

Specification:

A. Primary Containment. A. Primary Containment.

1. Whenever prienry containment is required, 1. Checks and inspections of the suppmssion the volume and temperature of the water structures, water level and temperature in the suppression chamber shall be shall be conducted as follovo

maintained within the following limits:

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(a) Water level and tempersture shall be

$ (a) thximum vater volume - 77,970 cubic checked once per day.

feet.

(b) '1he interior painted surfaces above (b) Minimum water volure - 68,000 cuble the water level shall be inspected feet. at each refueling outage.

(c) Fhximum water tempernture

1. During power operation, except l ns specified in item 1.(c).li below, 90 0F.

3.7/4.7 139 REI

l k.O GURVEILIAllCE REQUIREE"rNfS 30 LIllITII!G CONDITIO!G FOR OPERATIO!I 11, Inarleg testing which adds heat to the euppression pool - 100P F. (c) Whenever there is indication that them was relief valve operation with the "

Lli. Following a scrnm from a condition tempernture or the suppression pool I where the suppression pool teen- exceeding 160 F and the reactor vessel l ernture is 900 F or less, the pressure greater than 200 psig, an reactor pressure vessel chall be external visual exnmination of the depressurized at normal cooldown pressure suppression chamber shall be rates to less than 200 ps3g if the conducted before resuming power suppression pool temperature exce- operation.

eds 1200F.

iv. During power opernt ton if the temperature reachee 110 F the reactor shall be cernmmed immed-intely and depreccurized at notwil cooldown mtes to less than 200 poig.

(d) In order to continue power operation after exceeding the limit of 1.(e).1, the suppmssion pool temperatum must be mdaced to 90F within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

ir the temperature ennnot be reduced within this time litc!t, nomal reactor chutdown procedures chal.1 be initinted.

1h0 3 7/h.7 REV I

30 LIMITING conDITIom FOR OPERATION h.0 EUINEILLANCE REQUIEFIIENTS

2. Primary containment integrity as defined in 2. The primary containment integrity the Section 1, shall h maintained at all shall be demonstrated as follows:

time's when the reactor is critical or vbr.n the reactor unter temperature is above (a) Integrated Primary Containment 2120 F aal fuel is in the reactor vessel Icak Test (IPCLT) except while performing low power physics test nt atmospheric pressure durin6 or (1) An integrated leak rate test after refueling at power levels not to shall be performed prior to exceed S W(t). Initial unit operation at an initial test pressure (Pt) of I1 poig.

4 (2) Cubsequent leak nite tests shall te perfomed without preliminary leek detection surveys or leak repairs imediately prior to or during the test, at an initial pmesure of approximately 41 psig. ,

(3) leak mpairs, if necesscary to pemit integmted leak rate test- t ing, shall be preceded by local leak rate measurements where possible. The leak rate differ-3 7/4.7 140A REV

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_ + _ . _ _ _ _ _ _ _ _

^

Bases Continued:

37 A. primary Ccntainment length or aur feet, which resulted in complete condensation. Thus with respect to downcomer sutamergence, this specification is adequate.

and Bodega Bay (2)

The maximum temperature at the end of blowdown tested during the Humboldt Bay tests was 170 F and this is conservatively taken to be the limit for complete 0condensation of the reactor coolant, although condensation would occur for temperatures above 170 F.

In order not to exceed 170 F, immediately following a hypothetical O

loss of coolant accident, the maximum suppression pool temperature must not exceed 13O F durinn RCIC operation, assuming the min-imum suppression pool mass pemitted by these tech specs. Normally the pool temperature will be less than G0 F and will only rise during RCIC operation or testing of the HPCI system.

For an initial maximum suppression chuber water temperature of 90 F and assuming the normal com-plement of containment cooling pumps (2 LPCI pumpr and 2 containment cooling service water pumps) containment pressure is not required to maintain adequate net positive suction head (NPSH) for the core spray, LFCI and HPCI pumps. However, during an approximately one-day period starting s few hours after a loss-of-coolant accident, should one RHR loop be inoperable and should the containment pressure be reduced to atmospheric pressure through any means, adequate UPSH would not be available.

Since an extremely degraded condition must exist, the period of vulnerability to this event is re-l stricted by Specification 3 7. A.l.c by limiting the suppression pool initial temperature and the pr riod of operation with one inoperable RHR loop.

Experimental data indicates that excessive staam condensing loads can be avoided if the peak tempemture of the pressure suppression pool is maintained below 1600 F during any period of relief valve opemtion with conic conditions at the discharge exit. Specifications have been pinced on the envelope of reactor opemting conditions so that the reactor can be depressurized in a timely manner to nvoid the mgire of potentially high pmesure suppression charaber loadings.

(1) Robbins, C. H. , " Tests of Full Scale 1/148 Segment of the Humboldt Bay Pressure Suppression Contain ent," GEAP-3506, November 17,1%O.

(2) Bodega Bay Preliminary Hazards Summary Rcport, Appendix 1 Docket 50-205 December 28, 1962.

157 3 7 BASE rdN

1 Bases Continued 37 A. Primary Containment l If a loss of coolant accident were to occur when the reactor water temperature is below 330 F, ,'

l l the containmnt pressum will not exceed the 62 psig design pressum, even if no condensagion were to occur. he maximum allowable pool temperature, whenever the reactor is above 212 F,  ;

sin 11 be governed by this specification. Bus, specifying water volume-temperature requirements '

applicable for reactor unter temperatures above 212 F provides additional margin above that ,

avn11able at 330 F.

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3 7 BASES 157A [

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i Inces:

h.7 A. Primary Containment The wnter in the supprersion chnnber is usel only for cooling in the event of an accident; i.e., it is not used for nonnal opemtion; themfore, a weekly check of the temperatum and volume is adequate to assure that adequate heat removal capability is pmsent. For additional j

l margin, these will be checked once per day. m l l

Le requirment for an external visual examinntion followin6 any event whem potentially high Particular londingo could occur provides assumnce that no significant darnge was encountered.  !

attention should be focu. ed on structural discontinuities in the vicinity of the relief valve discharge since these are expected to be points of highest stmss.

Ee interiors of the dryvell and suppression chamber are painted to prevent rusting. We inspec-t1on of the paint durind each rnjor refueling outn6e sapproximately once per year, assures the pnint is intact and is not deteriorating. Experience with this type of paint indicates that the inspection interval is adequate.

We primarf containment pmoperational test pressures are based apon the calculated primarf containmnt pmssure recponse in the event of a loss of coolant accident. Be peak drywell prassure would be about 41 poig, which would rapidly reduce to 25 psig within 10 seconds follow-Irs, the pipe break. Following the pipe break, the suppression chamber pmssure rises to 25 psig within 10 seconds, equalizes with dryvell pmssure and thereafter rapidly decays with the dry-well pressure decay. See Section 5 2 3 FSAR.

psig. See Section 5 2 3 EAR. -

The design pressure of the dr/well and absorption chnaber isas56indicated above, the pressure Re design leak mte is O.Sf/ day at a pressum of 56 psig, response of the drywell and suppression chamber following an accident would be the same after about 10 seconds. Based on the enlculated containment pmssure response discussed above, the Also, based on the prirnry primarf containment preoperational test pressures vem chosen.

containment pressum response and the fact that the drywell and suppmssion chamber function as a unit, the primary containment will be tested as a unit rather than the individual components separately.

Be design basis loss of coolant accident was evaluated at the prirnrf containment maximum allowableaccidentleakrateof15%/dayat41psig. De analysis showed that with this leak 161 h.7 EASES REV

.TERIAL NRC Dibi RIDUTION FOR PART i'0 DOCKEl (T EMPOR ARY FO Rt/.)

3212 CON 1 ROL NO:

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Northern States Power C

• DATE OF DOC D AkE R E C'D LTR TWX RPT OTHER F ROM: Minneapolis, Minn. 55401 Mr. L.O. Hayer 3-24-75 3-26-75 X CC OTHER SENT AF.C PDR XXX TO: ORIG A. Giambusso 3 signed SENT LOCAL PDR XXX CLAES U NC L ASS PROPINFO INPUT NO CYS REC'D DOCKET NO:

XXX XXX 40 50-263 DESCRIPTION: ENCLOSUhES:

Ltr trans the following.... Amdt to the OL... consist of prop changes to tech speen....concertine new temperature limit ations for the suppression pool. . . .

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