ML20116J815
| ML20116J815 | |
| Person / Time | |
|---|---|
| Site: | 05200003 |
| Issue date: | 07/31/1996 |
| From: | WESTINGHOUSE ELECTRIC COMPANY, DIV OF CBS CORP. |
| To: | |
| Shared Package | |
| ML20116J585 | List:
|
| References | |
| SDG-4, NUDOCS 9608140087 | |
| Download: ML20116J815 (20) | |
Text
--
O BACKGROUND INFORMATION FOR AP600 SHUTDOWN EMERGENCY RESPONSE GUIDELINE SDG-4 O iP600 RESPONSE TO INCREiSING NUCtEiR EtUx DURING SHUTDOWN Rev.2 July 31,1996 WESTINGHOUSE ELECTRIC CORPORATION ENERGY SYSTEMS BUSINESS UNIT ADVANCED TECHNOLOGY BUSINESS AREA P.O. BOX 355 PITTSBURGH, PENNSYLVANIA 15230
- eR*22888K8tS888m F PDR sD o4 m 3196 REVISloN
- 2
l l
TABLE OF CONTENTS Section l Page '
l.0 INTRODUCTION 1-1 l l
l
2.0 DESCRIPTION
2-1 l,
i 3.0 RECOVERY / RESTORATION TECHNIQUE 3-1 3.1 l High-Level Action Summary 3-1 3.2 Key Utility Decision Points 3-3 !
4.0 DETAILED DESCRIPTION OF GUIDELINE 4-1 4.1 Detailed Description of Steps, Notes, and Cautions l 4-1 1 4.2 Step Sequence Requirements 4-12 O
l f
I i
I l
I l
O 1
1 SDG4 073196 j REVislON: 2 l
1 p
1.0 INTRODUCTION
l\
Guideline SDG-4, IESPONSE TO INCREASING NUCLEAR FLUX DURING SHUTDOWN, is a Shutdown Guideline (SDG) that provides procedural guidance if an unexpected increase in nuclear flux occurs during plant shutdown.
l There is only one explicit transition to guideline SDG-4. It is from the Shutdown Safety Status Tree, SDF-0.1, on an ORANGE priority when the nuclear flux doubling alarm does not clear.
After all the actions in guideline SDG-4 are completed, the operator is instructed to retum to the appropriate plant procedure.
l 0
l l
r\
l j l
l l
sDG4m3196 1-1 REVislON: 2 l
-l l
l
2.0 DESCRIPTION
Guideline SDG-4, RESPONSE TO INCREASING NUCLEAR FLUX DURING SHUTDOWN, provides actions to respond if the nuclear flux doubling alann will not clear indicating an abnonnal reactivity condition. This guideline is entered on an ORANGE priority from the Shutdown Safety Status Tree if the nuclear flux doubling alarm will not clear. The nuclear flux doubling alann could be reached if abnonnal reactivity conditions occur such as an inadvertent RCS dilution, an inadequate shutdown margin condition or if a fuel assembly is dropped, misplaced or, during fuel movement operations occurring close to the source range detector (s).
The actions of this guideline verify if fuel movement is in progress, checks to see if the nuclear flux is stable or decreasing, checks shutdown margin and verifies that all dilution paths are isolated. The operator would initiate boration of the RCS if required and detennine if any additional actions are needed based on plant status and conditions.
v
~
soo4m3196 2-1 REV!slON: 2
3.0 RECOVERY / RESTORATION TECHNIQUE dp The objective of the recovery / restoration technique incorporated into guideline SDG-4 is to provide actions to respond to an increase in nuclear flux during plant shutdown.
The following subsections provide a summary of the major action categories of operator actions and the key utility decision points for guideline SDG-4, RESPONSE TO INCREASING NUCLEAR FLUX DURING SHUTDOWN.
3.1 High Level Action Summary A high level summary of the actions performed in SDG-4 is given on the following page in the form of major action categories. These are described below in more detail.
- Check If Fuel Movement is In Progress If the reactor cavity is flooded then fuel movement may be in pmgress. Fuel movement adjacent to a source range detector may cause indicated nuclear flux to rapidly change to a new suberitical multiplication level. Fuel movement is stopped if an unexpected change to nuclear flux occurs to determine and correct the cause of the abnormal reactivity conditions.
Check RCS Shutdown Marcin Nuclear flux indication is checked to see if nuclear flux is stable or decreasing. An increasing source range flux count indicates an abnormal reactivity condition which could be caused by inadequate shutdown margin. RCS boration is initiated if nuclear flux is increasing. RCS shutdown margin is verified to be greater than the Technical Specification requirement. RCS boration is initiated, if required, to establish Technical Specification shutdown margin and isolation of all RCS dilution paths is verified.
- Detemiine if Any Additional Actions Are Necessary The operator is instructed to determine if any additional actions are necessary to address the abnormal reactivity conditions. This information may be needed to determine if the mitigating actions taken were successful.
O i
soc 443196 3-1 REVislON: 2
l l
l i
l MAJOR ACTION CATEGORIES IN SDG-4 f
- l Check If Fuel Movement Is In Progress !
Check RCS Shutdown Margin Determine If Any Additional Actions Are Necessary O
O soc 4a3196 3-2 REVISION: 2 i
3.2 Key Utility Decision Points There is one key utility decision point in this guideline when the operator must determine an appropriate course of action. In Step 6, the operator is instructed to determine if any additional actions are necessary to address the abnonnal reactivity conditions. The operator will determine if any additional actions are to be taken at this time in the guideline.
(v l
1 r )
U I
sDG4G3196 '
3-3 Revision: 2 I
l
4.0 DETAILED DESCRIPTION OF GUIDELINE This section provides a very detailed discussion of the generic guideline SDG-4 to facilitate EOP writing and training efforts. By presenting guideline background information in greater detail through the use of a structured format (i.e., step description tables, step sequence tables, and logic diagrams), applicability can be more easily determined. The separate and unique subsections containing this information follow.
4.1 Detailed Description of Steps, Notes, and Cautions This secha contains a one-page (or more) step description table for each separate guideline step, note, and caution. .'!O::: and cautions are always presented relative to the step they precede.
The Step Description Tables for the steps and associated notes and cautions of guideline SDG-4 are presented on the following page.
l i
I I
\ o sDG4-073196 41 Revision: 2
I STEP DESCRII'rION TABLE FOR SDG-4 l STEP 1 STEP: Verify CVS DW Isolation Valves - CLOSED PURPOSE: To ensure the CVS DW isolation valves are pmperly aligned BASIS:
The CVS DW isolation valves receive a signal to automatically close when a flux doubling signal is actuated. The operator should verify that the valves close as designed.
ACTIONS:
Determine if CVS DW isolation valves am closed
. Manually close CVS DW isolation valves INSTRUMENTATION:
CVS DW isolation valves position indication CONTROL /EOUIPMENT:
Switches for CVS DW isolation valves KNOWLEDGE:
N/A ADDITIONAL INFORMATION:
N/A O
soo4m3196 4-2 REvlsION: 2
-.. -.- . . . . . - - . - - _. . .~ - - . _ _ _ - . - .-_
STEP DESCRIPTION TABLE FOR SDG-4 l
i O STEP 2 l l
STEP: Verify Three Way Blend Valve - ALIGNED TO BORIC ACID TANK t PURPOSE: To ensure the three way blend valve is properly aligned BASIS:
Thethree way blend valve receives a signal to automatically close when a flux doubling signal is actuated. The operator should verify that the valve closes as designed.
ACTIONS:
. Determine if three way blend valve is closed o Manually close three way blend valve INSTRUMENTATION:
Three way blend valve position indication CONTROL /EOUIPMENT:
Switch for three way blend valve
/ KNOWLEDGE:
N/A ADDITIONAL INFORM ATION:
N/A O
SDo4m3196 4-3 REvlSION: 2
STEP DESCRIITION TABLE FOR SDG-4 STEP 3 STEP: Check Reactor Cavity - FLOODED PURPOSE: Status of the reactor refueling cavity is used to detennine if conditions are present for fuel movement.
BASIS:
This step instructs the operator to determine if the reactor refueling cavity is flooded (to the refueling water height). If the cavity is not flooded, then there would be no fuel movement in progress causing an abnormal reactivity condition and the operator then transitions to Step 3.
ACTIONS:
Determine if the reactor refueling cavity is flooded up to refueling hight.
INSTRUMENTATION:
Reactor refueling cavity level indication CONTROL /EOUIPMENT:
N/A KNOWLEDGE:
N/A ADDITIONAL INFORMATION:
N/A O
SDG4-om96 4-4 REVIsloN: 2 1
STEP DESCRIPTION TABLE FOR SDG-4
]v STEP 4 - NOTE NOTE: Fuel movement adjacent to a source range detector will cause indicated nuclear flux to change rapidly to a new subcritical multiplication level.
PURPOSE: To alen the operator that this anticipated reactivity change may occur.
BASIS:
l Fuel movement as a result of refueling operations includes placing higher reactivity fuel adjacent to source range detectors. Placing higher reactivity fuel adjacent to a source range detector will cause l
indicated nuclear flux to change rapidly to a new subcritical multiplication level. Fuel movement is '
stopped if an unexpected nuclear flux change occurs to determine and correct the cause of the abnormal reactivity conditions.
AQ10NS:
)
N/A i l
INSTRUMENTATION:
N/A CONTROL /EOUIPMENT:
N/A KNOWLEDGE:
l N/A l ADDITIONAL INFORMATION:
N/A l
l I
sDG4m3196 4-5 REVISION: 2
STEP DESCRIPTION TABLE FOR SDG..:
l I
STEP 4 l lI STEP: Stop Fuel Movement if Flux Change Is Unexpected PURPOSE: To stop fuel movement and core alterations if an unexpected reactivity change is !
occurring BASIS:
Fuel movement adjacent to a source range detector may cause indicated nuclear flux to rapidly change to a new suberitical multiplication level. Fuel movement is stopped if an unexpected nuclear flux change occurs to determine and correct the cause of the abnormal reactivity conditions. I ACTIONS:
i Initiate actions to stop fuel movement / core alterations INSTRUMENTATION:
Startup range nuclear flux indication CONTROL /EOUIPMENT:
N/A KNOWLEDGE:
Fuel movement adjacent to a source range detector will cause indicated nuclear flux to change rapidly to a new subcritical multiplication level.
ADDITIONAL INFORM ATION:
N/A O
sno4m3196 4-6 REVISloN: 2
i STEP DESCRIITION TABLE FOR SDG-4 l STEP 5 (V]
l STEP: Check Nuclear Flux - STABLE OR DECREASING l
PURPOSE: To determine if nuclear flux / reactivity is stable or decreasing BASIS:
Stable or decreasing nuclear flux irdicates that core reactivity is stable and that adequate shutdown margin is provided. Increasing or unstable nuclear flux, other than an expected change in flux (e.g.,
fuel movement adjacent to a source range detector will cause indicated nuclear flux to change rapidly to a new stable subcritical multiplication level), indicates a possible loss of adequate shutdown margin. Therefore RCS boration is initiated to recover shutdow71 margin.
l l
ACTIONS:
l Detennine if nuclear flux is stable or increasing initiate RCS boration if nuclear flux is unstable or increasing INSTRUMENTATION:
- Startup range nuclear flux indication
) i V -
RCS boration status inidication i
CONTROL /EOUIPMENT:
Controls for borating the RCS via CVS or PXS KNOWLEDGE:
Fuel movement adjacent to a source range detector will cause indicated nuclear flux to change rapidly to a new subcritical multiplication level.
ADDITIONAL INFORMATION:
Include AP600 specific details for initiating RCS boratien via CVS or PD.
l'
%s scour 13196 47 REVisloN: 2
STEP DESCRIIrrlON TAllLE FOR SDG-4 STEP 6 STEP: Check RCS Shutdown Margin - GREATER THAN TECH SPEC REQUIREMENT PlTRPOSE: To ensure the RCS baron concentration is gmater than that required for the appropriate Technical Specification (Tech Spec) shutdown margin BASIS:
The plant Technical Specifications require various amounts of shutdown margin depending on plant conditions (e.g., cold shutdown, refueling etc.). The operator checks RCS shutdown margin relative to the appmpriate plant Technical Specification based on intended plant conditions / operations. This step involves measuring and ensuring RCS boron concentration is greater than that required for the appropriate Technical Specification shutdown margin.
ACTIONS:
=
Det:rmine if RCS shutdown margin is greater than the appropriate Technical Specification Botate RCS to reestablish shutdown margin as required MSFRUhENTATION:
Instrument (s) to measure RCS boric acid concentration RCS boration status inidication CONTROL /EOUIPhENT:
Controls to borate RCS via CVS or PXS KNOWLEDGE:
N/A ADDITIONAL INFORMATION:
Include AP600 specific details for borating the RCS via CVS or PXS O
sDG4473196 4.g REVISION: 2
STEP DESCRIFFION TABLE FOR SDG-4 i
e STEP 7 STEP: Verify All Dilution Paths - ISOLATED l PURPOSE: Directs the operator to verify that all dilution padis to the RCS are isolated BASIS:
l Since the cause of inadequate shutdown margin and/or unstable or increasing nuclear flux can be
{
caused by unintended RCS dilution, the operator is instmeted to verify all RCS dilution padis are isolated, manually if required. i
)
ACTIONS: l l
Verify all RCS dilution paths are isolated l
l Manually isolate RCS dilution paths as required INSTRUMENTATION:
Dilution path (s) status indication CONTROL /EOUIPMENT:
Remote controls for isolating remote operated RCS dilution paths Local manual controls for manually isolating RCS dilution paths KNOWLEDGE:
N/A ADDITIONAL INFORMATION: 1 i
1 Include AP600 specific details for isolating all RCS dilution paths O
soc 4m3196 49 REV]slON: 2
i l
STEP PTSCRII' TION TABLE FOR SDG-4 ;
STEP 8 i
STEP: Determine If Any Additional Actions Are Necessary i
i PURPOSE: To determine if any additional actions are necessary to address the abnormal reactivity conditions BASIS:
)
This step instructs the operator to determine if any additional actiorts are necessary to address the j abnormal reactivity conditions. The operator is responsible for providing any funher actions to ;
address the abnormal reactivity conditions, if appropriate.
ACTIONS:
Determine if any additional actions are necessary INSTRUMENTATION: .
1 N/A l
)
CONTROL /EOUIPMENT: l N/A KNOWLEDGF,:
N/A ADDITIONAL INFORM ATION:
N/A i
l e
sDG4@31% 4 10 REVISION: 2
STEP DESCRIPTION TABLE FOR SDG-4 STEP 9 STEP: Go To Appropriate Plant Procedure PURPOSE:
To direct the operator to the proper procedure following completion of the steps in this guideline l
BASIS:
I l
Now that the guideline steps have been completed, the operator should continue plant operation and/or recovery by going to the appropriate normal or abnonnal plant procedure.
l l
ACTIONS: '
Go to appropriate plant procedure i INSTRUMENTATION:
N/A CONTROL /EOUIPMENT:
1 I
N/A l
O KNOWLEDGE:
l N/A ADDITIONAL INFORMATION:
N/A l
O ;
l spo4m3196 4-11 REVISloN: 2
- . .. . l
4.2 Step Sequence Requirements This section consists of a table which presents the existing guideline sequence and identifies the interchangeability of guideline steps for the benefit of the EOP writer.
The Step Sequence Table for SDG-4 is provided on the following page. The interchangeability of guideline steps is identified by the numbers in the column to the right of each guideline step.
O I
l 9
soo4-073196 4-12 Revision: 2
STEP SEQUENCE FOR SDG-4 STEP SEOUENCE
- 1. Verify CVS DW Isolation Valves - CLOSED 1
- 2. Verify Three Way Blend Valve - ALIGNED TO BORIC ACID TANK 1
- 3. Check Reactor Cavity Level - FLOODED 2 f
- 4. Stop Fuel Movement If Flux Change Is Unexpected 3
{
- 5. Check Nuclear Flux - STABLE OR DECREASING 4 i
- 6. Check RCS Shutdown Margin - GREATER THAN TECH SPEC REQUIREMENT 5
- 7. Verify All Dilution Paths -ISOLATED 6
- 8. Detennine If Any Additional Actions Are Necessary 7
{
- 9. Go To Appropriate Plant Procedure 8.
I t
O soc 4m3196 4-13 REVISION: 2