05000280/LER-1980-039-01, /01T-0:on 800626,potential Discovered for Boron Concentration Nonconservatism During Dilution Accident W/Rcs at Reduced Vol.Analysis of Boron Dilution at Cold & Hot Shutdown Being Evaluated by Reactor Vendor

/01T-0:on 800626,potential Discovered for Boron Concentration Nonconservatism During Dilution Accident W/Rcs at Reduced Vol.Analysis of Boron Dilution at Cold & Hot Shutdown Being Evaluated by Reactor Vendor

ML18139A433
Person / Time
Site:	Surry
Issue date:	07/08/1980
From:	Joshua Wilson VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML18139A432	List: 05000280/LER-1980-039, Forwards LER 80-039/01T-0 05000280/LER-1980-039-01, /01T-0:on 800626,potential Discovered for Boron Concentration Nonconservatism During Dilution Accident W/Rcs at Reduced Vol.Analysis of Boron Dilution at Cold & Hot Shutdown Being Evaluated by Reactor Vendor
References
LER-80-039-01T-01, LER-80-39-1T-1, NUDOCS 8007140259
Download: ML18139A433 (2)

LER-1980-039, /01T-0:on 800626,potential Discovered for Boron Concentration Nonconservatism During Dilution Accident W/Rcs at Reduced Vol.Analysis of Boron Dilution at Cold & Hot Shutdown Being Evaluated by Reactor Vendor

Event date:
Report date:
2801980039R01 - NRC Website

text

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80 I During steady state operation of Surry Unit No.lat 100% power and Unit No.2 at cold shutdown for steam generator replacement, it was discovered that a potential may exist for nonconservatism for Boron Concentrations of less that 2000 PPM when RCS has a

)))) 1 reduced volume and a dilution accident occurs.

The instrumentation installed detects

]:JD I the increase in Keff, AP-3 directs emergency boration during uncontrolled reactivity

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Im excursion.

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,- ATTACHMENT 1 SURRY POWER STATION, UNIT NO. l DOCKET:

• 50-280 REPORT NO:

80-039/0lT-O EVENT DATE:

6-26-1980 TITLE OF REPORT :

NONCONSERVATISM IN BORON CONCENTRATION

1.

Description of Event

During steady state operation of Surry Unit No.lat 100% power and Unit No.2 at cold shutdown for steam generator replacement, it was discovered that a potential may exist for nonconservatism in a dilution accident with Boron Concentrations of less than 2000 PPM and RCS at. a reduced volume.

2.

Probable Consequences/Status of Redundant Systems:

The instrumentation installed has the capability to indentify increasing Keff through the high flux at shutdown alarm functions. (Annunciator lG-17 and 2G-17).

AP-3 "CU:mcontrolled Reactivity Excursion Requiring Emergency Boration) directs_emergency boration during uncontr01led. reactiyit:y excursion.

Therefore the health and safety of the publice were not affected.

3; Cause of Ev.en11:***_,_

Analysis for boron dilution at cold shutdown and hot shutdown is not part of the licensing basis for Surry Unit No.land Unit No.2.

4.

Immediat~ Corrective Action:

OJ? 1.1 and OP-1.F determine the shutdown margin.

Annunciator lG-17 and 2G-17 detec~ ~ncrease i~ Keff" AP-3 directs emergency boration during uncontrolled reactivity excursion:.

5. Scheduled Corrective Action:

Boron Concentration as stated above is being evaluated by the reactor vendor.

6 Action Taken to Prevent Recurrence:

None Required

7.

Generic Implications:

Reactor vendor is evaluating the situation.