ML17298A662

Informs That Source Range Neutron Flux Monitor Not Required to Assure Reactivity Control Maintained from Remote Shutdown Panel,Per .Boron Dilution Event Does Not Affect Reactivity Control Function

ML17298A662
Person / Time
Site:	Palo Verde
Issue date:	11/23/1983
From:	Van Brunt E ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR
To:	Knighton G Office of Nuclear Reactor Regulation
References
ANPP-28284-WFQ, NUDOCS 8312010223
Download: ML17298A662 (6)

Text

REGULATORY M<FORMATION DISTRIBUTION SY M (RIDS)

ACCESSION NBR:831 FA'CIL:STN 50 528 STN-SO 529 STN 50 530 AUTH BYNAME VAN BRUNTgE ~ ED REC IP, NAtlE KNIGHTONg G ~

2010223 DOC ~ DATE: 83/11/23 NOTARIZED:

NO Palo Verde Nuclear Station< Unit ir Arizona Publi Palo 'Verde Nuclear Stations Unit 2g Arizona Publi Palo Verde Nuclear Station~

Unit 3i Arizona Publi AUTHOR AFFILIATION Arizona Public Service Co.

RECIP IENT AFFILIATION Licensing Br anch 3

DOCKET 05000528

'5000529 05000530

SUBJECT:

Informs that source range neutron flux monitor not required to assure reactivity control maintained from remote shutdown panel~per 830728 ltr.Boron dilution event does not affect reactivity control function.

DISTRIBUTION CODE:

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TITLE: Licensing Submittal:

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PHOENIX. ARIZONA 65036 November 23, 1983 ANPP-28284 WFQ/TFQ Director of Nuclear Reactor Regulation Attention:

Mr. George Knighton, Chief Licensing Branch No.

3 Division of Licensing U.S. Nuclear Regulatory Commission Washington, D.C.

20555

Subject:

Palo Verde Nuclear Generating Station (PVNGS)

Units 1, 2 and 3

Docket Nos. STN-50-528/529/530 File:

83-056-026; G.l.01.10

Reference:

(A) Letter from E. E.

Van Brunt, Jr.,

APS, to G.

W. Knighton, NRC, ANPP-23782, dated May 17, 1983.

(B) Letter from G.

W. Knighton, NRC, to E.

E.

Van Brunt, Jr.,

APS, dated July 28, 1983.

Dear Mr. Knighton:

By letter, Reference (A), we responded to your request to add a

source range neutron flux monitor to the PVNGS Remote Shutdown Panel (RSP).

By

letter, Reference (B),

you stated that our response did not meet the staff position with regard to monitoring source range neutron flux.

We would like to take this opportunity to restate our position on this issue.

The NRC staff concern is the loss of the reactivity control function from the Remote Shutdown Panel (RSP) due to potential boron dilution events caused by fire induced spurious operation of components.

At PVNGS, the RSP would be used only when the control room becomes uninhabitable.

Prior to evacuation of the control

room, the operator will trip the reactor and verify that all control rods are fully inserted.

PVNGS has such an extremely high control rod worth that it is impossible to achieve a critical state at any temperature or at anytime during a

fuel cycle provided that all rods are inserted.

This can be further realized by noting that the HOT (564'F)

Zero

Power, Beginning of Cycle (BOC),

clean critical all-rods-in boron level is estimated to be

-364 ppm. Allowing an additional 250 ppm for cooldown to approximately 60'F, there is still a shutdown margin equivalent to -114 ppm boron.

Thus, a

subcritical condition is maintained, assuming no boron in the

RCS, and all rods in.

This indicates that the occurance of a boron dilution event does not affect the reactivity control function.

, 8312010223 831123 PDR ADOCK 05000528 PDR' I

~I I

Mr. G.

W. Knighton Page 2

Therefore, a source range neutron flux monitor is not required to assure reactivity control is maintained from the RSP.

Please contact me if you have any questions on this matter.

E. E.

Van Brunt, Jr.

APS Vice President Nuclear Projects Management ANPP Project Director EEVB/TFQ/sp cc:

E. A. Licitra G. Wermiel A.

C.

Gehr