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EVALUATION OF FEBRUARY 26, 1984 SUBMITTAL BY MISSISSIPPI POWER AND LIGHT ON "0NSITE/0FFSITE POWER SUPPLY P,ELIABILITY", SECTION IV Summary of Submittal The, appl.icant in its submittal of Feb. 26, 1984 has presented a dis-cussion of an Onsite/0ffsite Power Enhancement Program for Grand Gulf Unit 1.
This program is, in part, a broad evaluation of the electrical
,4 plant requirements.
To support the electrical needs, the applicant has
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-t provided a' discussion of a preliminary evaluation of GGNS to withstand a station blackout (SBO) in Section IV of the submittal. The objective of the evaluation was to demonstr' ate that Grand Gulf could sustain a SB0 for a minimum of six hours without exceeding. containment. design con-ditions.
During the development of the govern.ing assumptions of this preliminary
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evaluation, the applicant elected to deviate fro 1. the normally assumed initial conditions associated with DBA analyses. The most notable changes are associated with reactor conditions.
The core was assumed to be at "Beginning of Life" with decay energy determined by ANS 5.1 and power level at 75% of design. As stated by the applicant, these more realistic assumptions were appropriate at this stage of evaluation.
Additional assumptions which were identified in the discussion include; (1) Manual action to depressurize the reactor pressure vessel to about 200-300 psi at a rate of 100*F/hr.
(2) Loss of all containment heat removal capability i
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t (3) Loss of containment sprays (4) Upper pool dump not considered (5) Containment heat sinks considered 4
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RCIC available (8)
Condensate storage tank available for 6.1/2 hours (9) SRV and ADS available The applicant, using the ground rules described above has performed an evaluation of the containment response.
The result shows that Grand Gul,f can sustain the postulated event for a minimum of six hcurs without exceeding the containment design pressure of 15 psig (thE specific calculated response was not provided).
With respect to containment temperature, the applicant indicates the containment temperature
. response would be less than 225'F for at least seven hours.. This is above the design temperature of 185*F.
However, the applicant has indicated that the transmitters for RPV level and pressures are " judged" to be capable of operation at about 225*F.
Since they are an important consideration to core cooling availability it was concluded by the applicant th'at GGNS can conservatively withstano av SB0 for in excess of six hours during power ascension up to 75% power.
Staff Position Section IV, Plant Performance Under a Loss of AC Power Event, of the Onsite/Offsite Power Enchancement Program for Grand Gulf Unit 1 is mmewev...-
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unacceptable as a justification for fu'l power operation bec'ause it l
lacks substance and is self-contradictory.
No analyses are presented.
Specific items which need to be addressed, corrected -or substantiated are'given below:
,.f 1.
There is an assumption that the loss of AC power occurs at 75%
power.
Unless there is certainty that the onsite AC power sources e
will be fully qualified prior to exceeding 75% power, this is unacceptable since your application was for full (100%) power.
2.
There is a statement in the first paragraph that "ofhEr assumptions used in the evaluation are conservative".
What are the other assumptions?
3.
Provide the analyses which support the conclusion reached in section 4 of your submittal.
4.
Upon loss of the air compressor following a SBO, the ADS has the
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capacity to provide only two actuations of each valve and then hold the valve open. However, you assume that the operator takes action to depressurize the reactor to about 200 to 300 PSI at rate of 100*F per hour.
This would require multiple actuation of the ADS valves.
What is the source of air for these multiple actuatiens?
Are these actions consistent with your emergency procedures (they are not consistent with the emergency procedure guidelines)?
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7 You state that the diesel-driven fire pump can be aligned to supply he 5.
water to the containment to provide additional heat sink capacity.. h d
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h Lateryou state that the same system can be used as a backup source g#,
Ay-to RCIC.
Does the fire pump have sufficient head to act as a
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back-up to RCIC? Can it be aligned to pump into the vessel? p
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p 6.
Without calculating control room temperature, you state that "The 'nue, sew peak temperature which develops within the first ten hours of the SB0 event would not be expected to adversely affect equipment
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o.peration".
What is the basis for this statement?J h/hyd. cyn for* F?
7.
You state that " Violation of the (RCIC) room temperature limit would not result in immediate loss of equipment".,Co.nsidering that the RCIC system will isolate on high room temperature, justify this f, p., ym end.
statement.
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8.
In one paragraph you state " Grand Gulf could sustain the postulated event 'for a minimum of six hours without exceeding containment design pressure".
In another you state "... Containment factors are still limiting".
In yet another, you state" The containment,
design pressure is not reached in the six hour period after the event". What are the limiting containment factors?
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9.
You state" The RCIC suction is assumed to be switched to condensate s' orage within one hour of the transient".
Isn't RCIC suction t
normally aligned to the condensate storage tank? At what point in.
the-transient would RCIC suction automatically transfer to the
. suppression pool due to indicated high wa.ter level in the pool?
10.
Provide the temperature - Pressure transient profiles for both the dryweklandcontainmentfortheevaluatedSBO,inclu'dethetimeof manual interaction, the actions that are necessary, and the
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information the operator uses to determine the above actions are necessary, 11.
Provide a list of systems and instrumentation that are assumed to be available for the SB0 transient.. Include justification for the assumed availability in view of temperature responses of (10).,
12.
It is indicated that drywell cooling is a significant 1oss and manual actions are necessary to limit drywell temperatures to (fi7 within design.
Since drywell cooling has been previously indicated as a non-safety system explain the basis of the above statenent.
13..
Provide the heat transfer coefficient to the heat sinks, heat sink surface areas, thicknesses and thermal properties and the heat l
transfer / mass transfer coefficent between pool and contairrent atmosphere that were used in the SB0 analysis.
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14.
Provide the mass'and energy tabulated data computed to enter the pool via the SRV's as a function of time for the SB0 event.
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15.
Provide the mass and energy data assumed to enter the primary i
l' system via the condensate storage tank.
16.
Provide all initial values'of parameters important to the containment response. These should include pool volume and temper-ature, drywell/ containment temperature and pressu5.'
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