ML19347C818

AO 73-26:on 731010,average Power Range Monitor Scram & Rod Block Setpoints Not Set to Conservative Values Specified in Tech Specs.Caused by Personnel Error.Procedures Will Be Reviewed W/Personnel

ML19347C818
Person / Time
Site:	Oyster Creek
Issue date:	10/16/1973
From:	Ross D JERSEY CENTRAL POWER & LIGHT CO.
To:	Giambusso A US ATOMIC ENERGY COMMISSION (AEC)
References
AO-73-26, NUDOCS 8103040879
Download: ML19347C818 (3)

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Begulatory Doc,qet ;,e Jersey Central Power & Light Company MAD! SON AVENUE AT PUNCH BOWL ROAD

• MORRISTOWN, N.J.07960

• 201-539-6111 m.aa m General g Public Utilities corporation m.

October 16, 1973

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Ftr. Giambusso Wluna% q['f'] a Deputy Director for Reactor Projects . ll- OCT 021973 v ? ' j.

Directorate of Licensing 5 ,

• OCISOIO/Ja., [E' United States Atomic Energy Commission [$$fThi -1 I~ N.he.;r g<yt.f g q?*s Washington, D. C. 20545 onn, c'.IrI. 9 h L

Dear Mr. Giambusso:

D c[ W h= G Subj ect:- Oyster Creek Station ;- S (,

Docket No. 50-219 APRM Set Point The purpose of this letter is to report a failure to set to average power range monitor scram and rod block set points to the conservative values specified in Technical Specifications 2.3(1)(a) and 2.3(2)(a). This event is considered to be an abnormal occurrence as defined in the Technical Specifi-cations, paragraph 1.15.A. Notification of this event, as required by the Technical Specifications, paragraph 6.6.2.a, was made to A.EC Region I, Directorate of Regulatory Operations by telephone on October 10, 1973, and by telecopier on October 11, 1973.

On October 6,1973 at 2:00 p.m. , the reactor startup to full power had been halted due to a lack of in-service condensate demineralizers. The core thermal output at this time was approximately 567 FfWt and the recirculation flow rate was 30x106 lbs/hr. At this time, the maximum total peaking factor (PF) was estimated to be 4.54 and the average power range monitors (APRM's) were set conservatively such that 100% on the APRM's corresponded to 1200 MWt. This is equivalent to reducing the neutron flux scram by the amount 3.01/PF as specified in Technical Specifications 2.3.1.a, with some added margin. The 100'./1200 MWt setting allows for a neutron flux peaking up to a value of 4.84.

At 5:30 p.m. , after a heat balance calculation, the setting of the APRM's was inadvertently set such that 100*6 of the APRM's corresponded to 1400 MWt I which accounts for peaking factors of only 4.15. Thus, the limiting safety system setting for the APRM neutron flux scram and rod block were set less con-servatively than specified in the Technical Specifications 2.3.1.a and 2.3.2 a.

Near the conclusion of the reactor core operations, the engineer assisting in core monitoring performed a " quick" heat balance and performed the final peaking factor checks. He determined the maximum peak location and value flo3o M 7f w

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Mr. - Giambusso October 16, 1973

- and' as 'a result advised the control room operator to adjust the APRM's to the -

conservative 100'. - 1200 MWt setting. The control room operator made the

-recommended adjustment and entered the new setting in the control room log.

Four errors on the part of four individuals then occurred:

1. Prior to leaving the plant, the engineer failed to notify the shift foreman, whose presence was required in another part of the plant at the time, of the final condition of the reactor Core.

2. Upon reviewing the control room log at the end of the shift, the shift foreman failed to notice the relevant log entry.

3. The control room operator failed to notify both the shift foreman upon his return to the control room and the relief control room  ;

operator of the new APRM setting. [

4. The relieving control room operator failed to review the prior shift log entrie's.

As a result of the " quick" heat balance, no documentation of the correct setting was provided on a heat balance power range work sheet. The relieving control room operator, after performing the heat balance power range for his shift, used the last documented heat balance as the basis for the APRM setting. l This setting was in agreement with the value forwarded to the relieving shift foreman. The final result was the 100S. == 1400 MWt setting of the APRM's.  ;

At 10:30 a.m. on October 7,1973, the reactor neutron flux peaking  ;

factor was estimated as required in Technical Specifications 4.1, Table 4.1.1. , l Note 2, and found to be 4.71. The APRM's were then correctly adjusted to-the conservative 100%/1200 MWt setting. ,

Based on the neutron flux , peaking factor of 4.71, as estimated at the time of the-correction, the safety limit can be shown to be at 1228 MWt for the recirculation flow rate of 30x10 6 lbs/hr. Using the 100%/1400 MWt setting  ;

< of the APRM's, the reactor at this condition would have scrammed at 1200 MWt, L if required. Thus, the safety limit would not have been exceeded. }

I To prevent a reoccurrence of this incident, the following actions will  !

be taken:  ;

1. The technical supervisor will issue a memorandum to the appropriate engineers re-emphasizing the'ir advisory capacity in core oper-ations and the necessity of informing the shift foreman of plant .

status following any control rod manipulation or power level l

changes.

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Mr. Giambusso ' October 16, 1973 i

2. The operations supervisor will review with the shift foremen all requirements for reading and initialing control room log book entries. This will be accomplished via a memorandits from 4

the operations supervisor.

Enclosed ar? forty (40) copies of this report.

Very truly yours,

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s/ W Donald A. Ross Manager, Nuclear Generating Stations DAR:cs Enclosures cci Mr. J. P. O'Reilly, Director Directorate of Regulatory 0perations, Region I s

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