ML20116J823
| ML20116J823 | |
| Person / Time | |
|---|---|
| Site: | 05200003 |
| Issue date: | 07/31/1996 |
| From: | WESTINGHOUSE ELECTRIC COMPANY, DIV OF CBS CORP. |
| To: | |
| Shared Package | |
| ML20116J585 | List:
|
| References | |
| SDG-5, NUDOCS 9608140092 | |
| Download: ML20116J823 (15) | |
Text
_ -
I
- O l
BACKGROUND INFORMATION FOR AP6 o SHUTDOWN EMERGENCY RESPONSE GUIDELINE SDG-5 O
iP6 o RESPONSE TO COtD OVERPRESSURE DURING SHUTDOWN Rev.2 i
July 31,1996 WESTINGHOUSE ELECTRIC CORPORATION ENERGY SYSTEMS BUSINESS UNIT ADVANCED TECHNOLOGY BUSINESS AREA P.O. BOX 355 j
PITTSBURGH, PENNSYLVANIA 15230 O
DR ADO 052 03 F
PDR SDG5@3196 REVISION: 2
TABLE OF CONTENTS Section M
1.0 INTRODUCTION
1-1
2.0 DESCRIPTION
2-1 3.0 RECOVERY / RESTORATION TECHNIQUE 3-1 3.1 High-Level Action Summary 3-1 3.2 Key Utility Decision Points 3-3 4.0 DETAILED DESCRII' TION OF GUIDELINE 4-1 4.1 Detailed Description of Steps, Notes, and Cautions 4-1 4.2 Step Sequence Requirements 4-8 O
l l
9 spos-073196 i
REVISION: 2
i
1.0 INTRODUCTION
Guideline SDG-5, RESPONSE TO COLD OVERPRESSURE DURING SHUTDOWN, is a Shutdown Guideline (SDG) that provides procedural guidance if RCS temperature and pressure are not within the cold overpressure limits during plant shutdown.
l There is only one explicit transition to guideline SDG-5. It is from the Shutdown Safety Status Tree, SDF-0.1, on an ORANGE priority when RCS pressure and temperature are not within the cold overpressure limits.
After all the actions in guideline SDG-5 are completed, the operator is instnicted to retum to the appropiiate plant procedure.
l I
I l
i i
l i
4 4
SDG5-0731%
l-l REVIsloN: 2
2.0 DESCRIPTION
Guideline SDG-5, RESPONSE TO COLD OVERPRESSURE DURING SHUTDOWN, provides actions to respond if RCS temperature and pressure conditions are not within cold overpressure limits during plant shutdown conditions. This guideline is entered on an ORANGE priority from the Shutdown Safety Status Tree if RCS cold overpressure limits are exceeded, as dictated by the RCS pressure-temperature limits within the plant Technical Specifications. Examples of when the cold overpressure limits could be exceeded are from an unintended RCS mass injection, an RCS letdown /RCS makeup flow mismatcn, or starting an RCP under water solid RCS conditions with uneven RCS temperatures and no RCPs operating.
The actions of this guideline decrease RCS pressure to within the Technical Specification pressurr-temperature limits, checks if all RCPs should be stopped and determines the cause(s) or corrective actions to be taken for the cold overpressure condition.
O O
sDosa3196 2-1 REVISION: 2
3.0 RECOVERY / RESTORATION TECHNIQUE The objective of the recovery / restoration technique incorporated into guideline SDG-5 is to provide actions to respond to an RCS cold overpressure condition.
The following subsections provide a summary of the major action categories of operator actions and the key utility decision points for guideline SDG-5, RESPONSE TO COLD OVERPRESSURE DURING SHUTDOWN.
3.1 High Level Action Summary A high level summary of the actions performed in SDG-5 is given on the following page in the fonn of major action categories. These are described below in more detail.
Depressurize RCS Pressure To Within Technical Specification Pressure - Temperature Limits i
Since RCS temperature cannot be changed (increased) rapidly to mitigate a cold overpressure condition, RCS pressure is promptly decreased to mitigate the cold overpressure condition.
If the RCS is water solid, RCS pressure is decreased by increasing letdown and decreasing RCS makeup. If a pressurizer steam space is present, auxiliary spray or one set of first stage pressurizer ADS valves is used to depressurize the RCS.
Check If All RCPs Should Be Stopped i
Starting an RCP with uneven RCS temperatures (e.g., a hot SG while remainder of RCS is cold) with a water solid RCS can result in heat addition type cold overpressure events. Also staning an RCP with multiple RCPs operating while the RCS is water solid my result in RCS pressuit transients exceeding cold overpressure limits. Therefore if an RCP has just been stmed which Insulted in exceeding the cold overpressure limits, as determined by the Shu.Jown Safety Status Tree, all RCPS are stopped to stabilize RCS pressure.
l
_Dr.tennine Cause of RCS Pressurization And If Any Additional Actions Are Necessary The operator is instructed to determine the cause of the RCS pressurization and if any additional actions are necessary to address the abnonnal RCS pressure conditions. This information may be needed to determine if the mitigating actions taken were successful.
l soc 5m3 96 3-1 Revision: 2
MAJOR ACTION CATEGORIES IN SDG-5 Depressurize RCS Pressure To Within Technical Specification Pressure - Temperature Limits Check If All RCPs Should Be Stopped Detennine Cause of RCS Pressurization And If Any Additional Actions Are Necessary 9
1 6
Ol SDG543196 33 REVISION: 2
j 1
3.2 Key Utility Decision Points There is one key utility decision point in this guideline when the operator must detennine an appropriate course of action. In Step 4, the operator is instructed to determine if any additional actions are necessary to address the abnormal RCS pressure-temperature conditions. The operator will determine if any additional actions are to be taken at this time in the guideline.
- sDG5 0731%
3-3 PavistoN: 2
l l
4.0 DETAILED DESCRIPTION OF GUIDELINE 1 v This section provides a very detailed discussion of the generic guideline SDG-5 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 i
diagrams), applicability can be more easily detennined. The separate and unique subsections containing this information follow.
l l
4.1 Detailed Description of Steps, Notes, and Cautions 1
This section contains a one-page (or more) step description table for each separate guideline step, note, and caution. Notes 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-5 are i
presented on the following page.
t l
I l
i l
O
)
i 5
I i
- D05 s 3196 41 Revision: 2 i
I STEP DESCRII'rION TABLE FOR SDG 5 STEP 1 STEP:
Decrease RCS Pressure To Within Tech Spec Pressure-Temperature Limits PURPOSE:
To decrease RCS pressure to within Technical Specification pressure-temperature limits BASIS:
Since RCS temperature cannot be changed rapidly (without generating excessive thermal stresses) to correct for the cold overpmssure condition, RCS pressure is lowered to the appropriate Technical Specification pressure-temperature condition based on the prevailing RCS cold leg temperature.
RCS cold leg temperature is used for this pumose since the critical / limiting component being protected is the reactor vessel belt line region walls, which see downcomer or cold leg fluid temperatures.
ACTIONS:
Determine if RCS is water solid Decrease RCS pressure by increasing letdown and decreasing RCS makeup Decrease RCS pmssure by using auxiliary spray
=
Decrease RCS pressure by using one set of first stage PRZR ADS valves INSTRUMENTATION:
PRZR level indication CVS letdown flow indication RCS makeup flow indication RCS cold leg temperature indication RCS pressure indication Auxiliary spray status indication PRZR first stage ADS valves status indication
=
CONTROL /EOUIPMENT:
Controls for:
CVS letdown RCS makeup Auxiliary spray
=
PRZR first stage ADS valves l
KNOWLEDGE:
i N/A ADDITIONAL INFORMATION:
N/A l
spasm 3196 4-2 REvlsloN: 2 i
(
I STEP DESCRIfTION TABLE FOR SDG 5 l
STEP 2 STEP:
Check If All RCPs Should Be Stopped
)
PURPOSE:
To instmet the operator to stop all RCPs if an RCP has just been started with a water solid RCS resulting in a cold overpressure condition l
l BASIS:
l Staning an RCP with uneven RCS temperatures (e.g., a hot SG while remainder of RCS is cold) l with a water solid RCS can result in heat addition type cold overpressure events. Also staning an i
RCP with multiple RCPs operating while the RCS is water solid my result in RCS pressure l
transients exceeding cold overpressure limits. Therefore if an RCP has just been started which resulted in exceeding the cold overpressure limits, as detennined by the Shutdown Safety Status l
Tree, all RCPS are stopped to stabilize RCS pressure.
l ACTIONS:
l Detennine if an RCP hr tust been started with a water solid RCS Stop all RCPs INSTRUMENTATION:
RCP operating status indication 1
,CONTROUEOUIPMENT:
RCP controls KNOWLEDGE:
l N/A ADDITIONAL INFORMATION:
l N/A j
i i
i LO SDG5@3196 43 REvlsION: 2
STEP DESCRIFFION TABLE FOR SDG-5 STEP 3 STEP:
Detennine Cause Of RCS Pressurization PURPOSE:
To instruct the operator to detennine the cause of the RCS pressurization resulting in a cold overpressure condition BASIS:
Cold overpressure events are caused by an inadvertent RCS pressurization as opposed to rapid temperature changes. The root cause of RCS pmssurization is detennined so that the operator can determine if additional actions are needed as instructed in the next step.
ACTIONS:
Determine cause of inadvenent RCS pressurization INSTRUMENTATION:
N/A CONTROL /EOUIPMENT:
N/A KNOWLEDGE:
N/A I
ADDITION AL INFORM ATION:
N/A i
e sDa5473196 44 REVislON: 2
i STEP DESCRIITION TABLE FOR SDG 5 t
STEP 4 STEP:
Determine if Additional Corrective Actions Are Necessary j
t PURPOSE:
. To determine if any additional corrective actions are necessary to address the cause for the cold overpressure condition BASIS:
f f
This step instructs the operator to determine if any additional corrective actions are necessary for addressing the cause of the cold ovegressure condition. The operator is responsible for providing any further actions to address the cause of the cold overpressure condition, if appropriate.
ACTIONS:
I Determine if any additional corrective actions are necessary to address the cause of the cold
)
overpressure condition.
INSTRUMENTATION:
N/A CONTROL /EOUIPMENT:
O N/A KNOWLEDGE:
l If the RNS relief valve had opened to limit any overpressurization, the operator should verify that it has properly rescated once pressure is below its lifting pressure ADDITIONAL INFORMATION:
N/A O
SDG5@3196 45 Revision: 2
STEP DESCRII' TION TABLE FOR SDG-5 STEP 5 STEP:
Go To Appropriate Plant Procedure PURPOSE:
To direct the operator to the proper procedure following completion of the steps in this guideline BASIS:
Now that the guideline steps have been completed, the operator should continue plant operation and/or recovery by going to the appropnate normal or abnormal plant procedure.
ACTIONS:
Go to appropriate plant procedure INSTRUMENTATION:
N/A CONTROL /EOUIPMENT:
N/A KNOWLEDGE:
N/A ADDITIONAL INFORMATION:
N/A l
1 l
O l
SDG5@3196 46 REVISION: 2
l 1
4.2 Step Sequence Requirements GI j
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-5 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.
()
I i
l 1
N spos 073196 47-REVisloN; 2
STEP SEQUENCE FOR SDG-5 STEP SEOUENCE 1.
Decrease RCS Pressure To Within Tech Spec Pressure-Temperature Limits 1
2.
Check If All RCPs Should Be Stopped 2
3.
Detennine Cause Of RCS Pressurization 3
4.
Determine if Additional Corrective Actions Are Necessary 4
5.
Go To Appropriate Plant Procedure 5
O' l
l 9
SDG5-073196 4-8 REVisloN: 2