ML20034C775

Issue 57 to Abnormal Operating Procedure AOP-B, Reactor Scram

ML20034C775
Person / Time
Site:	Fort Saint Vrain
Issue date:	04/19/1990
From:	PUBLIC SERVICE CO. OF COLORADO
To:
Shared Package
ML20034C092	List: ML20034C091 ML20034C775 ML20034C776 ML20034C777 ML20034C778 ML20034C779 ML20034C780 ML20034C782 ML20034C783 ML20034C784 ML20034C785
References
AOP-B, NUDOCS 9005100025
Download: ML20034C775 (4)

Text

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l AOP-B Issue 57 FORT ST.'VRAIN NUCLEAR CENERATIN3 STATION Page 1 of 2

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issue 57 Page 2 or 2 I

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REACTOR SCRAM SYMPTOM-ACTt04 MATRIX li I

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I SYMPTOMS I

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1.1 1

1.2

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ISta rtup Count loseutron reux Itoss or Plant t l

l ACTIONS Irate High IRMS-Irate of Change i Nr l

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IHigh (ISS-Starti s 03g g

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l I-03B IUp) 8-038 8 4-2, :r-e, 6-2 I I

i l 4-4, 5-4, 6-4 I 4-3, 5-3, 6-3 l l

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OPERATOR ACTIOst i

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I 2.1 1

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I ansert manual sc ram.

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I I 2.2 I

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I Ensure reactor internal l XX i XX l XX I

I I maintenance terminated.

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1 I 2.3 I

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l Ensure atI PCRV openings I XX 1 XX l XX l

-l 1 closed.

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l Monitor Critical Safety I XX XX 1 XX XX l. XX XX l l

l Tunctions per EOP's.

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l AOP APP B Issue 57 Public FORT ST. VRAIN NUCLEAR GENERATING STATION age 1 of 2 P

service

• Pusuc saRVME COMPANY OF COLORADO O

INTRODUCTION Reactor scram is the ultimate defense against any circumstance or condition that threatens to damage the reactor core and release radioactive fission products. Reactor scram is initiated automatically by the Plant Protective System (PPS) in a number of C

l situations described in the following discussion of symptoms.

The specific PPS actions that are initiated by reactor scram are as

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follows:

1.

The control rod brakes are de energized.

2.

Power to Rod Drive Motor Control Centers (N-9225, East and N-9226, West) are interrupted (K49-51 and K48-50 green lights on - Board I-10).

3.

First-in scram annunciator and indicating light are actuated, indicating which logic channels have tripped A,

B, or C.

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DISCUSSION OF SYMPTOMS SYMPTOMS 1.1 Startup Count Rate High (RMS Fuel Loading) 1-03B 4-4, 5-4, 6-4 This scram is actuated when either source range nuclear channel equals or exceeds a neutron countrate of 1.0E+5 counts /second I

with the Reactor Mode Switch not in the RtJN position, The scram action is initiated by 1 of 2 logic trip by the Nuclear Start-up Channels I or II.

1.2 Neutron Flux Rate of Change High (ISS Start-Up) 1-03B 4-3, 5-3, d

This scram is actuated as a result of Wide Range Nuclear Channels III, IV or V equaling or exceeding a neutron flux rise I

of 5 DPM.

O FORM (Ol372 22 3643 lh

l AOP APP B e

Issue 57

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& Public FORT ST. VRAIN NUCLEAR CENERATING STATION age 2 of 2 P

%27 Service

• Pusuc sanvece comeAmy or cotonApo O

l 1.3 Loss of Plant power I-038 4-2, 5-2, 6-2 Undervoltage detectors sense the voltage on all three phases of all three essential buses, Detection of voltage loss persisting for 30 seconds by 2 of the 3 detectors on 2 of the 3 busses will produce. 2 of 3 scram channel trips, causing a reactor scram.

l The accident of concern.is the loss of outside power, and failure of one diesel generator to start. A scram is required l

to allow for heat removal with less than a normal complement of I

plant equipment.

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DISCUSSION 0_F OPERATOR ACTION 2.1 Insert manual scram.

l Insert manual scram following automatic scram as a backup to the PPS to insure a full scram. A manual scram can be inserted by operating the scram handswitch to the scram position, by.

depressing two of three push buttons on I-49, or by placing the RMS (Reactor Mode Switch) to the off position.

Inward rod Q

motion and decreasing flux are observed to verify that the scram V

is having the desired effect.

I 2.2 Ensure reactor internal maintenance terminated j

l The operator should advise any personnel involved in operations from the refueling floor that a scram has occurred and that further operations should be terminated until it is determined to be safe to proceed.

l 2.3 Ensure all PCRV openings closed Openings through the PCRV should be closed as soon as possible l

to prevent the out leakage of primary coolant and potential release of activity.

4 l 2.4 Monitor Critical Safety Functions per E0P's.

l If the operator verifies that any critical safety function is j

l not being met, the operator will proceed to appropriate E0P.

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FORM (Ol372 22 3843

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