ML20091A254

Errata to NEDO-20846,Rev 1, ATWS Study for Monticello Nuclear Generating Plant

ML20091A254
Person / Time
Site:	Monticello
Issue date:	11/10/1975
From:	GENERAL ELECTRIC CO.
To:
Shared Package
ML20091A252	List: ML20091A248 ML20091A254
References
NEDO-20846-ERR, NEDO-20846-ERR-R01, NEDO-20846-ERR-R1, NUDOCS 9105140465
Download: ML20091A254 (9)

Text

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l RegulM0l]h.0pdhd yecx> ,os,,

Class I Rev.1. May 1975 l

daleyvsl ANTICIPATED TRANSIENTS WITHOUT SCRAM STUDY FOR THE '

MONTICELLO NUCLEAR GENERATING PLANT l

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BOILING WATER RE ACTOH PROJECTb DEPARTMENT

• GENERAL ELECTHIC COMPANY SAN JOSE, CAllF ORNI A 95125 GEN ER AL $ ELECTRIC 9105140465 751110 PDR ADOCK 05000263 p PDR l

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) NF00-20846 i

i j 2. ANALYSIS GUIDES AND RESULTS

'l i

l 2.1 REACTOR COOLANT SYSTEM PRESSURE i

d WASH 1270 requires companson of pnmary stress to that of the emergency Conditons of the ASME Nuclear Power l

l Plant Component Code Section Ill On consideration of this guido and enamination of the system, the WASH 1270 guide j transtates to a vessal pressure of 1500 psg. NEDO 10349 uses 2700 psg as the vessel pressure that can be aCCommo-l dated wtthout structural failure.

1

! 2.2 FUEL THERMAL AND HYDRAULIC PERFORMANCE WASH 1270 requires evaluation of any fuel cladding degradation or significant fuel melting. These sub lects. inclucing portinent failure mechanisms, were discussed at length in NEDO 10349. Section 5.1.3. The applicaten of the guide does not change from that made in the previous report With respect to prompt failutes, an energy depositon guide of 280 cal /gm has been selected. It has been shown that fragmentation is avoided at oxidation levels of less than 17% by volume 20 CONTAINMENT CONDITIONS

] ,

j WASH 1270 requires companson of containment pressure to the design pressure. The containment design pressure a

for the Monticello Plant is 56 psg NEDO 10349 uses the membrane yield hmit of the pnmary containment which is 108 psig, as a guide.

) 2.4 SUMM ARY OF RESULTS I

) Table 21 summarizes the results of the analyses i

4 Table 21 j

SUMMARY

OF RESULTS 1 MONTICELLO NUCLEAR GENERATING PLANT i

l MSIV CLOSURE WITH FAILURE TO SCRAM l Bounding Value

! by Analysis j with RPT, l Feedwater System Modification, i Parameter and 5 minute SLC Initiated j Vessel Pressure (psig) 1307 4

l Fuel Entha!py (cal /gm) <150 i

Cladding Oxidaten (%) <1 i

Containment Pressure (psg) 6.9 J

1 May 1975 4-i

l l

NEDO 20846 l

l 3.3 EQUIPMENT CHARACTERISTICS I

l The charactenstes of the important pieces of equipment used to mitigate the consequences of failure to scram are i

tsted in Table 3 2 I

j Table 3-2 i EQUIPMENT 'ERFORMANCE CHARACTERISTICS i

Charactortatic Para m eter i

Relief Vatve System Capaaty r .JBR Rated Steamflow). .

.,7 4.4

]

. . . - . . .1080 + 1% I Rehof Vatve Setpoent Range (p6U ..

Rehef Vatve Time Delay (sec). .04 Relief Valve Opening Time (sec).. . 3.1 Control Liquid injection Rete por Pump (gpm). .28 Delay Time from Control Liquid initiation to begin Shutdown (sec).. . 30 l HPCI Flow Rate (Ib/sec).. .415 RHR HX Effectiveness (Otu/sec F). .200 Reorc Pump Tnp Reactor Pressure or Water Level Sensor and Logic Time Delay (sec) . . .0.53 Reorc Pump System inertia Constant (sec) . .5 i

The long term effects of an ATWS event depend in part on initiation of additional equipment to nutigate the consequences. The initiation times for which credit is taken in the vanous analyses are:

Standby Liquid Control System: Initiaton - 5 minutes after the event RHR System: initiation - 10 minutes after the event 4

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Figure 41, Monticello MSIV Closure Transimt - A DVS Response with A nVS Modifications May 1975 9' i

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j Fogure 4 4. Monticello MSIV Closure Transient - A TWS Containment Response with A1WS Modifications l

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1 NEDO 20846 1

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j 4.3.3 Containment i

j For purposes of this report. the term containment will be used to melude the drywell as well as all those enclosed i spaces wruch are affected by the steam released to the suppression pool Response refers to the actiori of the pressure and j hmperature in the containment as steam is released to the suppression pool and drywell.

J.

] All steam passes through the rehef valves and enters the suppression pool. All steam that enters the poolis assumed

{ 10 be condensed and the pool temperature is effected accordngly Both RHR heat exchangers are assumed to be actuated j at 10 minutes. but the energy from the steam release exceeds their heat removal Capacity at the eruttal tempurature ao that pool temperature continues to increase until the RHR heat exchangers capacity is equal to the energy being generated by decay heat i Contamment pressure will aiso increase atong with pool temperature The containment pressure transient is shown in Figure 4 4. The rnmmum containment pressure is 7.3 psig, which is within the guide values 4.4 COMPARISON TO WASH 1270 l Appendix A. paragraph II.C 1 of WASH 1270 requests comparison of three functons to specified analytical guides.

j Table 41 provides a companson of the analytical results witn the WASH 1270 and General Electnc guidet Table 4-1

SUMMARY

OF RESULTS I

MONTICELLO NUCLEAR GENERATING PLANT l

! MSIV CLOSURE WITH FAILURE TO SCRAM i

I, Bounding Value by Analysis Functional WASH 1270 General Electric with RM, Feedwater System

{ Comparison Comparison Suggested Modification, and l Parameter Value Guide 5-min. SLC Initiation j Vessel Pressure (psig) 1500 2700 1307 ,

,i i Fuel Enthalpy (cal /gm) 280 280 <150 l.

j Claddng Oxidation (%) 17 17 <1 l Containment Pressure (psg) 56 108 6.9 I,

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v 1200 l 7 9 q1 VOID REACTIVITY COEFFICIENT (e/1Q FM A 1. Monticello ATWS Renee with A TWS Modifkations - MSIV Cheurs Traculent MW 1975 16-1

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