ML20084U072

Forwards Proprietary Responses to Discussion Items of 910403 Ge/Nrc Reactor Sys Branch Conference Call,Per 900703 Submittal of Amend 13 to Advanced BWR Ssar,Chapter 18.Encl Withheld

ML20084U072
Person / Time
Site:	05000605
Issue date:	04/10/1991
From:	Robare D GENERAL ELECTRIC CO.
To:	Chris Miller NRC, NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML19302E425	List: ML20084U072
References
EEN-9123, MFN-037-91, MFN-37-91, NUDOCS 9104150190
Download: ML20084U072 (5)

Text

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GE NucIcar Energy s

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April 10,1991 MFN No.037 91 Docket No. STN 50 605 EEN.0123 Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Attention: Charles L. Miller, Director Standardization and Non. Power Reactor Project Directorate

Subject:

GE Responses (Proprietary information) to Discussion items of April 3,1991, GE/NRC Reactor Systems Branch Conference Call

Reference:

Submittal of Amendment 13, Proprietary Information, to GE's ABWR SSAR, MFN No. 077 90, dated July 3,1990 Enclosed are thirty four (34) copies of the GE responses to the subject :liscussion items.

Responses to the discussion items contain information that is designated as General Electric Company proprietary information. This material relates to the Chapter 18 proprietary information that was previously sent to the NRC (Reference) and its corresponding proprietary affidavit.

It is intended that GE will amend the SSAR, as appropriate, with these responses in a future amendment.

Sincerely, D.J. Robare, Acting Manager Regulatory and Analysis Services M/C 382, (408) 925 6948 cc: F. A. Ross (DOE)

D. C. Scaletti (NRC)

G. Thomas (NRC) p'(

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D. R. Wilkins (GE) U '

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l J. F. Quirk (GE) ( h g,, \ l t 3% $

9104150190 910410 PDR ADOCK 05000603 A PItR

l 4 0 4-RESPONSES TO DISCUSSION ITEMS OF APRIL 3.1991 CE/NRC CONFERENCE CALL ,

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NO. 1 In the Introduction section p.1 The following sentence in Rev. 4, EPO is deleted in the ABWR EPd. " Suppression pool, 1 drywell.and containment temperature are determined by plant specific procedures for determinin6 bulk suppression pool water temperature, drywell atmospheric average tempora-ture, and Mark III containment atmospheric average tempera-ture, respectively."

The above sentence should be kept since it is applicabic for

ABWR except for the reference to Mark III containment atmo-spheric average temperature.

RESPONSE

In the ABWR design, the average bulk suppression pool tempera-ture is calculated by the individual system microprocessor an displayed to the operator. Individual temperature _ signals from different locations can.be also be displayed.- [Same dis-plays are also availabic at the Remote' Shutdown Panel. ) The temperature processing ~ algorithm will include sensor failure detection and uncovery of sensor due to changes in suppression pool water level. _All signals _to the main control room are multiplexed, and hence performing calculations is simple.=

Refor_to SSAR Subsection 7.6.1.7 for a description of the sup- i pression pool temperature monitoring system.

The'drywell' atmospheric average temperature will be treated;in the same manner as the-suppression pool average bulk tempera -

ture. (See Subsection 7.5.2.l(2)(j)] .

No. 2 OnlPage 1 2, it-is stated that "Conformance with the guide.

' lines does not ensure = strict conformance with a plant techni-cal. specifications or other licensing basis," This statement is misleading and confusing. -The: staff is developing a posiv- '

tion on the _ issue of, EPG versus licensing basis. We are work-

'ing with the BWR-Owner's Group on this issue. The-quoted' statement will need to be revised to reflect our position as it is. finalized.

RESPONSE

.We are aware of this issuei We will revise this statement when your position on it is finalized.

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hiO. 3 Add the following abbreviations to Table 1 (18A): ilSBW llot Shutdown Boron Weight, MSCWL Minimum Steam Cooling Water Level. In Chapter 6.3, the abbreviation "LPFL" is used to de-scribe the LPCI mode of RilR In Table 1, "LPCF" is used.

Which is correct?

RESPONSE

MSCWL, Minimum Steam Cooling Water Level, and llSBV, Hot Shut-down Boron Weight were added to Table 1. LPFL will be used throughout the EPC. (During the conference call LPCF was in- t

.dicated rather than LPCF). LPCF will be changed to LPFL, all ,

places, in the next amendment.

NO. 4 In Caution #5, ilPCF pump and in RilR pump (Page RC 5) NPSil values are given for suppression chamber overpressure (SCO).

SCO is equal to suppression chamber (SC) airspace pressure +

water head'over suction strainer. Regulatory Guide 1.1 does not allow credit for SC airspace pressure. Describe in detail the advantage of SCO on the required. IlPCF and RilR pump NPSil values given in Caution #5 and on Page RC 5. Provide cor-rected NPSil values.

RESPONSE

The' method for using the SCO is already established in EPG Rev. 4. This approach is consistent with the philosophy of using realistic analysis as opposed to licensing type analysis methods. No changes are required.

NO. 5 In the RPV control guidelines entry conditions, the following condition "or RPV water level cannot be determined" should be added to "The RPV water level below level scram setpoint".

RESPONSE

The proposed statement is not currently in EPG Rev 4. We are '

aware that the BVROG is working on this issue. We will change the ABWR EPC when its position is finalized.

NO. 6 The suppression pool temperature versus ' reactor power curve for step RC/Q-6 is missing. Include the curve as given in the EPG, Rev. 4 l

L RESPONSE:

With the FMORD .Run In functional, . the control rods are fully inserted in approximately two minutes with the motor drives.

During the rod insertio_n, analysis results show that with a

~ failure to scram with the hydraulic accumulators and with the FMCRD Run In function operational, suppression pool tempera-ture can be as high as 135"F (57.2*C). We have included the ,

I. boron injection initiation temperature curve and revised step RC/Q 6 as shown on page 18A.4 14.

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h10. 7 Step'RC/Q. 7.1 Resetting the ARI logic is not included in the ABWR EPG. ARI is in the ABVR design. Table 1.8B 1 does not explain why this step _is deleted.

RESPONSE

The ABVR EPG was revised to retain step RC/Q-7.1 (page 18A.4 15), resetting of ARI logic as follows:

" Reset ARI, bypassing ARI logic trips is necessary."

NO. 8 STEP RC/Q 72, " Reset the scram defeating RPS logic trips if necessary" is deleted. . Table 18B 1 provides the explanation that it is not applicable for ABWR, Since there is a RPS for ABVR, a more detailed justification for the deletion is neces-sary.

RESPONSE

Step RC/Q 7.2 has been retained as follows:

" Reset the scram, bypassing RPS logic trips if necessary, and initiate a manual scram."

]

The phrase " drain the scram discharge volume" in EPG Rev. 4 is not applicable to the ABWR_because it does not have a scram discharge volume.

Table 18B 1 (page 18B 6) has been revised accordingly. .

NO. 9 The Step C2 2 directs the operator to enter contingency #3 l steam cooling rather than step- RC/P-4 specified in the EPG, Rev. 4. The Table'18B 1 does not explain why this deviation is taken.

RESPONSE

This was a word processing error. The reference to RC/P 4-in Step C2 2,_has been changed.

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N0c 10 The suppression pool temperature versus reactor power curve- 'l for step C5-2 is missing. Include the curve as given in EPG, l Rev. 4..

i RESPONSE: I The boron inj ection initiation temperature curve has_ been addedl(page 18A.12 2).

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NO. 11 In the EPG Rev. 4, Step C6 3, RPV venting is performed irre.

spective of the radioactivity release rate. But in the ABWR EPG, RPV venting is performed if containment radiation is  ;

below the core damage radiation level. What is the difference in the RPV- venting philosophy? Table 18B 1 does not ade-quately explain the basis for RPV venting. Explain in detail the ABWR RPV venting philosophy and revise Table 18B+1 accord-ingly (Ref: Step C6 3).

RESPONSE

o In the ABWR EPG, RPV venting is performed if containment radi.

ation level is below the core damage radiation level. This is v to preclude releasing radioactivity outside of the primary containment and is believed to be a more conservative approach than that adapted in EPG Rev. 4.

Furthermore, if containment radiation is high indicative of core damage, the containment will be flooded only to the bottom of the RPV as indicated by the override statement for Step C6-2. Flooding to the bottom of RPV in the presence of core damage will avoid covering the vent-pipes leading to the containment overpressure protection rupture disks. This strategy is designed to avoid discharing water into the vent path (should containment pressure exceed rupture disk pres.

sure) which could result in damage to the equipment in the vent path.

Table 18B 1 has been revised (for Step C6 3) accordingly.(page 18B 23).-

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