ML20084S824

Ao:On 750408,expected Increase in Reactor Power Noticed Due to High Pressure Heat or Open Bypass Valve ,Resulting in Reactivity Increase.Caused by Inadvertent Contact W/ Switch.Rods Inserted

ML20084S824
Person / Time
Site:	Quad Cities
Issue date:	05/07/1975
From:	Kalivianakis N COMMONWEALTH EDISON CO.
To:	Oleary J Office of Nuclear Reactor Regulation
References
NJK-75-268, NUDOCS 8306170443
Download: ML20084S824 (2)

Text

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J. F. O' Leary, Di rector ' tby 7, 1975 -

temperature and flow changes result in a calculated reactivity increase of 0.17%.

Supplement A to Unit 2 Cycle 2 Reload Submittal-(also applicable to Unit

1) contains an analysis for,a cold water. transient due to loss of a 100 F feedwater heater. This analysis gives the folicning:

Peak Neutron Peak Heat Peak Steamline Peak Vessel Fl ux , % Flux, % Pressure, PSI G Pressure, PSIG 115 114.7 1005 1053 The ratio of the actual temperature transient to the analyzed transient is, 17oF 1000F = 17%

The analyzed heat flux (lC0oF) increase of 14.7% multiplied by 17% g!ves a calculated heat flux increase of 2.5% for the actual transient.

The actual thermal power increase was 2539 fut

'2T74 lut = 1.026 or a 2.6% increase This shcus excellent agrecrunt between calculated and actual transient

.A anan,c:c y

i The cause of this event is attributed to inadvertent contact wi th the swi tc h \ ~

controlling t10-1-3203 This swi tch is located on the ext reme fo rwa rd .nc . t i on of control par.el 301-6 and is spring loaded to return to its normal position I follorring actuation.

Corrective action consisted of inserting rods and decreasing recirculation flow to bring the transient under control and within normal limits. Sub-sequently, D0-1-3203 was again closed and normal power operation was resumed.

In addition, a work request (1258-75) was issued to inspect the valve c!cc-t rical ci rcui ts, flo discrepancies were noted at the breaker or in any of the valve cont rols.

This event had no ef fect on the health and safety of the public because the cold water transient was inn.ediately controlled. In addition, it is noted that the results of this transient conpare favorably with the tran- )

sient analysis provided. i i

Sincerely, COMMONVEALTH EDIf 0N COMPAMY QUAD-CITIES JUCLES POWEP. STATION

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k h *3fkW??f N. J. Ka ivianakis .'

Station Superintendent HJK/lk 8306170443 750507 PDR ADOCK 05000254 S PDR u _ _ - _ _ - _ _ _ _ _ _ _ _ _ _ ~ _ _ _ _ _ _ _ _ _ _ _ _ . ___ _ -

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. m-n:t j Mr. John F. O' Leary, Di rector

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Directorate of Licensing Regulation ' , V rr-' ' ,\'

U. S. Nuclear Regulatory Commission Washington, D. C. 20545

Reference:

quad-Ci tics Nuclear Power Station Docket.No. 50-254, DPR-29 Appendix A, Section 6.6.8.2.b.

Dea r Mr. O' Leary :

The purpose of,ts letter is to provide you wi th details concerning an unusual event which occurred at quad-Ci ties Nuclear Power Station, Uni t

~. One, on April 8, 1975 This report is subnii tted to you in accordance wi th wthe requi rements of Technical Speci fication 6.6.B.2.b.

At 12:45 p.m. on April 8 with. Unit 1 operating at 818 KJc, the Ursit 1 op-crator noticed an unexpected increase in reactor power. He immediately

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began inserting rods and decreased recirc flow to 775 lue. He then dis-covered the high pressure heater bypass valve (M0-1-3203) had opened re- j sulting in a reactivity increase due to the lower reactor fe Jwater inlet '

temperature.

This had resulted in the folloaing conditions:

INITIAL FINAL Feedwater Temperature ( r;) 338 321, tMe 818 820 tut 2474 2539 Feedwater Flow (Mlb/hr) 9 75 10.0 Core Flow (Mlb/hr) 97 5 97 5 The decreased feedwater temperature caused a core inlet subcooling change of 2.425 CTU/lb. Using an inlet subcooling reactivity coefficient of 0.07 AK/DTU/lb (derived from General Electric Core Management Engineering Ana-molies Surveillance Curve for Quad-Ci ties Unit I Cfcle 2), the feedwater i

5382 COPt 6ENr itEGION $ _

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