ML17299A577
| ML17299A577 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 08/30/1985 |
| From: | ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR |
| To: | |
| Shared Package | |
| ML17299A576 | List: |
| References | |
| 02-NS-110, 02-NS-110-R00, 2-NS-110, 2-NS-110-R, TAC-59247, NUDOCS 8509050207 | |
| Download: ML17299A577 (21) | |
Text
PVNGS 02-NS-110
- 10CFR50, APPENDIX R SAFE SHUTDOWN EVALUATION OUTSIDE CONTROL ROON FIRE SPURIOUS ACTUATION STUDY FOR THE PALO VERDE NUCLEAR GENERATING STATION UNIT 2 STUDY 02-NS-110 REVISION 0
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Table of Contents 1.
INTRODUCTION
~Pa e
1.1 Scope 1.2 Objective 2.
SUMMARY
3.
CONCLUSIONS AND RECOMMENDATIONS 3.1 3.2 3.3 3.4 3.5 General Operational Considerations Fire Zone:
1 Fire Zone:
2 Fire Zone:
3A Fire Zone:
3B 8
8 9
9 10 4.
Outside Control Room Fire Spurious Actuation Evaluation Ground Rules 10 4.1 NRC Requirements 4.2 Assumptions and Bases 5.
Outside Control Room Fire Spurious Actuation Evaluation Logic LIST OF TABLES 10ll 14 Table No.
Title 3-1 Fire Event Safe Shutdown Systems Outside Control Room Fire Evaluated Fire Zones Fi ure No.
NS-110-1 Figures Title Outside Control Room Fire Spurious Actuation Evaluation Logic
PVNGS 02-NS-110 l.
INTRODUCTION 1.1 SCOPE Evaluate the impact of fixe-induced hot shorts, open circuits and shorts to ground in electrical circuitry which are routed different from Unit 1 for each fire zone outside the control room on the ability to safely shut down the plant using the safe shutdown (SSD) systems listed in Table l-l, both with and without offsite power.
1.2 OBJECTIVE The objective of this evaluation is to define any necessary special operating, procedure requirements and/or design changes to ensure safe shutdown capability within the operational time constraints.
2.
SUMMARY
Fire-induced hot shorts, open circuits and shorts to ground in electrical circuitx'y can result in the spurious actuation and/or inability to control components, which can impact the capability to achieve safe (cold) shutdown.
To assess the extent of the potential fire damage on safe shutdown, the electrical circuitry in each of the fire zones identified in Table 3-1 has been evaluated.
The conclusions and recommendations derived for Unit 1 are applicable for Unit 2; additional Unit 2 specific findings are presented in section 3.
3.
CONCLUSIONS AND RECOMMENDATIONS For postulated fires outside the control room, Table 3-1 lists all fire zones evaluated.
Only those that were found to impact the ability to achieve SSD have been included in this section.
For each fire zone, this s'ummary identifies:
o Evaluation Findings Potential undesirable spurious control actions/inactions of Unit 2 systems which are different from Unit l.
o Key Monitorable Parametexs (functional)
Those available parameters which enable the operator to identify and mitigate the consequences of spurious control action/inactions, and to reach and maintain a safe (cold) shutdown are listed.
These parameters are electrically and physically independent of the fire being evaluated.
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PVNGS 02-NS-110
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Time Constraints Critical time constraints for system or components operation are quantified.
Operational Considerations The necessary action(s) required to prevent the adverse effects of the spurious control action/inactions summarized in the evaluation findings're detailed.
Compensatory Measures The recommendations to accomplish each of the operational considerations are presented.
These compensatory measures vill be available to the plant operators for post-fire shutdown.
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PVNGS 02-NS-110 TABLE l-l FIRE EVENT SAFE SHUTDOWN SYSTEMS System AF CH CT DF DG EC
~Sstem Auxiliary Feedwater Chemical and Volume Control Condensate Storage and Transfer Diesel Fuel Oil Storage and Transfer Diesel Generator Essential Chilled Water HD HJ HS PB PE PG PH PK Essential Cooling Water HVAC - Auxiliary Building HVAC Diesel Generator Building HVAC Control Building HVAC - Ancillary Building (Spray Pond Pump House) 4160V-ac Class 1E Power Class lE Standby Generating System 480V-ac Class 1E Power 480V-ac Class 1E Power 125V-dc Class lE Power PN RC SG SI SP 120V-ac Class lE Power Reactor Coolant System Main Steam Safety Injection and Shutdown Cooling Essential Spray Pond 3146r
PVNGS 02-NS-110 TABLE 3-1 (Sheet 1 of 4)
OUTSIDE CONTROL ROOM FIRE EVALUATED PIRE ZONES FIRE ZONE~
SSD TRAIN SUBJECT TO DAMAGE SSD TRAIN TO BE USED FOR FIRE NOTES'ire Area 1<a>
CONTROL BUILDING
, Fire 1
3A 4A SA 6A 7A 8A 9A 10A llA 15A 18A 20 86A Area II A
A A
A A
A A
A A
A A
A A
A See See No No No No No No No No No No No No findings findings findings findings findings findings findings findings findings findings findings findings findings findings 2
3B 4B 5B 6B 7B 8B 9B 10B llB 12 13 14 15B 18B 19 86B B
B B
B B
B B
B B
B Neither Neither B
Neither Neither Neither B
A A
A A
A A
A A
A A
A A
A A
See See No No No No No No No No No No No No No No No findings findings findings findings findings findings findings findings findings findings findings findings findings findings findings findings findings
~~No safety-related raceway in the zone.
>Fire areas and zones are defined in PSAR Appendix 9B.
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PVNGS 02-NS-110 TABLE 3-1 (Sheet 2 of 4)
OUTSIDE CONTROL ROOM FIRE EVALUATED FIRE ZONES FIRE ZONE(
SSD TRAIN SUBJECT TO DAMAGE SSD TRAIN TO BE USED FOR FIRE NOTES:
MAIN STEAM SUPPORT STRUCTURE Fire Area XII 72 73 74A 74B A
B A
B AUXILIARYBUILDING No findings No findings No findings No findings Fire Area XIII 30A 31A 32A Fire Area XIV No findings No findings No findings 30B 31B 32B Fire Area XV 33A 33B 87A 87B 89 90 88A 88B 34A 34B 3SA 35B 36 37A Neither Neither A
Neither iQeither Neither Neither B
A B
A B
Neither A
B A
B A
A B
B A
B A
B A
B B
No findings No findings No findings
<<No findings "No findings No findings
<<<<No findings
<<<<No findings
<<<<No findings
<<No findings No findings No findings
,No findxngs No findings No findings
<<<<No findings No findings
<<No raceway in the zone.
<<No safety-related raceway in the zone.
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PVNGS 02-NS-110 FIRE ZONE<<>
37B 37C 37D 37E 39A 39B 42C 42D 43 44 45 46A 46B 46E 48 49A 49B 49C 49D 49E 49F 49G 49H 50A 50B 51A 51B 52A 52D 53 54 55A 55C 55E 56A 56B 56C 57A 57B 57C SSD TRAIN SUBJECT TO DAMAGE B
A B
Neither Neither B
B Neither A
Neither A
B Neither B
Neither Neither Neither Neither Neither Neither Neither Neither B
Neither Neither B
A B
B B
Neither iNeither Neither Neither A
A Neither A
Neither TABLE 3-1 (Sheet 3 of 4)
SSD TRAIN TO BE USED FOR FIRE B
A A
B A
A B
B B
B B
A A
B B
B B
B B
B B
A A
A A
B A
A A
B B
B B
B B
B B
B NOTES:
No findings No findings No findings
<<<<No findings No findings No findings No findings No findings No findings No findings
<<<<No findings No findings No findings No findings No findings
<<No findings
<<No findings
<<No findings
<<No findings
<<No findings
<<No findings
<<No findings
<<<<No findings No findings
<<<<No findings
<<<<No findings No findings No findings No findings No findings No findings
<<<<No findings No findings No findings No findings No findings No findings
<<<<No findings No findings
<<<<No findings
<<No raceway in the zone
<<<<No safety-related raceway in the zone.
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PVNGS 02-NS-110 TABLE 3-1 (Sheet 4 of 4)
FIRE ZONE<<>
SSD TRAIN SUBJECT TO DAMAGE SSD TRAIN TO BE USED FOR FIRE NOTES'7D 57E 57F 57G 57H 57I 57J 57K 57L 57M 57N 57P Neither Neither Neither Neither Neither A
A Neither Neither Neither A
A
<~No
'k'@No
~~No
+~No
>+No No No
+~No
><No 4'O'No No No findings findings findings findings findings findings findings findings findings findings findings findings Fire Area XVI 42A 47A Fire Area XVII No findings No findings 42B 47B
<~No safety-related raceway in the zone.
A A
No findings No findings 3146r
PVNGS 02-NS-110 3.1 GENERAL OPERATIONAL CONSIDERATIONS 1.
For a fire in any given fire zone, safe shutdown is to be accomplished using the Table 3-1 identified safe shutdown systems for that specific fire zone.
2.
Isolate the control room HVAC by manual initiation of CRVIAS upon indication of a control building fire outside the control room, In addition, for a fire in Fire Zone 1, override and stop essential AHU M-HJA-F04 and for a fire in Fire Zone 2, override and stop essential AHU M-HJB-F04.
3.
To preclude intolerable spurious concerns for outside the control room fires, the pending plant changes/operational considerations must be implemented:
place the breaker for SDC suction valves J-SIC-UV-653 and J-SID-UV-654 in the open condition during normal plant operating conditions when RCS pressure is greater than the SDC system suction isolation interlock setpoint.
~
To prevent a fire in Fire Zone 42C from disabling all charging
- pumps, the Train A charging pump low suction pressure switch (J-CHA-PSL-216) separation concerns are to be resolved as part of the Appendix R separation review efforts.
~
The atmospheric dump valve (ADV) nitrogen supply must remain operable.
4.
To ensure availability of a borated water source to the charging
- pumps, the RWT gravity feed flow path through air-operated valve J-CHN-HV-32 (fails open) and motor-operated valve J-CHE-HV-536 is designated as Train A while the RWT gravity feed flow path through motor-operated valve J-CHB-HV-530 and manual valves CHV327, and CHV755 (Train A charging pump) or CHV756 (Train B charging pump) is designated as Train B.
The train defined to be used for safe shutdown in the event of a specific fire identified in Table 3-1 along with the evaluation findings for that fire zone will ensure proper charging
.pump suction alignment.
(The basis for designating the flow paths as Train A or Train B is the physical location of the valves.)
3.2 FIRE ZONE:
1 (for a fire in this zone, use SSD Train B) 1.
Evaluation Findin Loss of pressurizer pressure control may occur due to spurious opening of pressurizer spray valve J-CHA-HV-205 2.
Ke Monitorable Parameters (Functional)
Pressurizer pressure 3146r
PVNGS 02-NS-110 3.
Time Constraints:
Not applicable (see compensatory measures) 4.
0 erational Considerations:
Stop pressurizer auxiliary spray flow to prevent uncontrolled RCS depressurization.
5.
Com ensator Neasures:
To overcome spurious uncontrolled RCS depressurization, stop charging flow and open disconnect switch DS-09-07 at auxiliary relay cabinet E-Zhh-C03 to close J-CHA-HV-205 3.3 Fire Zone:
2 (For a fire in this zone, use SSD Train h) l.
Evaluation Findin Loss of pressurizer pressure control may occur due to spurious opening of pressurized spray valve J-CHB-HV-203 2.
Ke Nonitorable Parameters (Functional)
Pressurizer pressure 3.
Time Constraints:
Not applicable (see compensatory measures) 4.
0 erational Considerations:
Stop pressurized auxiliary spray flow to prevent uncontrolled RCS depressurization 5.
Com ensator Measures:
To overcome spurious uncontrolled RCS depressurizations, stops charging, flow and open disconnect switch DS-09-12 at auxiliary relay cabinet E-ZhB-C03 to close J-CHB-HV-203 3.4 FIRE ZONE:
3h (for a fire in this zone, use SSD Train B) l.
Evaluation Findin Loss of pressurizer pressure control may occur,due to spurious opening, of pressurizer spray valve J-CHh-HV-205 2.
Ke Nonitorable Parameters (Functional)
Pressurizer pressure 3146r
PVNGS 02-NS-110 3.
Time Constraints:
Not applicable (see compensatory measures) 4.
0 erational Considerations:
Stop pressurizer auxiliary spray flow to prevent uncontrolled RCS depressurization 5.
Com ensator
?measures:
To overcome spurious uncontrolled RCS depressurization, stop charging flow and open disconnect switch DS-09-07 at auxiliary relay cabinet E-Zhh-C03 to close J-CHh-HV-205.
3.5 FIRE ZONE:
3B (for a fire in this zone, use SSD train h) l.
Evaluation Findin Loss of pressurizer pressure control may occur due to spurious opening of pressurizer spray valve J-CHB-HV-203 2.
Ke Honitorable Parameters (Functional)
Pressurizer pressure 3.
Time Constraints:
Not applicable (see compensatory measures) 4.
0 erational Considerations:
Stop pressurizer auxiliary spray flow to prevent uncontrolled RCS depressurization.
5.
Com ensator Measures:
To overcome spurious uncontrolled RCS depressurization, stop charging flow and open disconnect switch DS-09-12 at auxiliary relay cabinet E-ZhB-C03 to close J-CHB-HV-203 4.0 OUTSIDE CONTROL ROON FIRE SPURIOUS hCTUhTION EVhLUhTION GROUND RULES l.
No accidents are assumed concurrent with the fire.
2.
Cold shutdown must be achieved and maintained with and without offsite power.
3.
hs the consequence of the fire, hot shorts, open circuits, or shorts to ground must be considered.
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Where hi/low pressure interface is involved (RCS only), any number of fire-induced actions/inactions must be postulated.
4.2 ASSUMPTIONS AND BASES 1 ~
Either the Train A or the Train B fire event safe shutdown components and monitorable parameters identified in FSAR Table 9B.1-4 will be operable following any fire event.
Basis:
Appendix R train separation is provided for the FSAR Table 9B.1-4 components.
2
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The worst case combination of spurious actuation of the device under consideration and fire damage to circuits of other components in the fire zone will be evaluated.
In addition, the effects of hot
- shorts, shorts to ground and opens on ESFAS initiating and power supply circuits shall be evaluated.
Basis:
This assumption considers that a fire will damage more than one circuit in the fire zone but not necessarily all circuits.
No other components with circuits in the same fire zone can be used to mitigate the effects of the spurious actuation under consideration; conversely, the action/inaction of these components combined with the spurious actuation may preclude safe shutdown.
3.
A spurious control signal action/inaction shall be defined as being caused by a single hot short, open circuit, or short to ground, impacting a single component.
Basis:
4 ~
Each electrically-operated component has its own unique control circuits, which may be affected by the single hot short, open circuit, or short to ground.
Fire-induced failures in three-phase power cables can only result in a loss of power to, or the inability to supply power to, the component.
Basis:
Hot shorts in three-phase power circuits resulting in maintained contact are not considered credible.
5.
The conditions stated in Assumption 2 can be assumed to occur at any time following the onset of the fire event, until action is taken to defeat or preclude the action/inaction from occurring.
3146r PVNGS 02-NS-110 Basis:
Because of the Appendix R mandate to achieve and maintain cold
- shutdown, the plant can be in any of its normal operating modes (i.e.,
Modes 1-6) at the initiation of the fire event.
6.
For offsite power available, all equipment not affected by the fire will remain in its refire condition( i.e., condition during normal plant operation for the assumed mode).
For loss of offsite power, all equipment goes to its loss of offsite power design failure position.
(NOTE:
One strategy may be to selectively shed power from equipment/buses to minimize adverse spurious action/inaction impact.)
Basis:
The basis for this assumption is simply that the components/systems will function as designed, with the exception of the single spurious actuation.
7.
The analysis of fire damage will be performed on a fire zone basis and only components in safety-related systems will be considered.
Basis Generic Letter 81-12 allows for the choice of evaluating spurious actuation on a fire area or systems basis.
The security system monitoring of plant fire detection systems identifies fire situations on a fire zone basis and alerts the operators of an incipient fire.
Using the result of a fire zone analysis, the operators can take immediate action for the affected zone and anticipate safe shutdown system alignment needs for the possibility of fire spreading to adjacent zones.
The inherent plant design is such that the safe shutdown equipment listed in FSAR Table 9B.1-4 can overcome any effects by nonsafety-related systems on the capability to achieve safe shutdown.
The fire event safe shutdown systems are identified in Table 1-1.
8.
There will be some time interval between the onset of the fire event (time t=O) and that time when the operator can reasonably be expected to be able to counter the adverse effects of the spurious action/inaction.
(This time interval should be quantified.)
Basis:
This assumption is intended to reflect the "real world" situation an operator may face as a result of a fire.
The evaluation will define necessary operational considerations and applicable time constraints necessary to aid an operator in assessing overall plant conditions and controlling the plant.
9.
Protection of nonsafe shutdown equipment is not a priority item of this evaluation.
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PVNGS 02-NS-110 Basis:
The Appendix R mandate is to achieve and maintain cold shutdown to protect the health and safety of the public.
10.
All plant operating modes except refueling will be evaluated (i,e.,
Modes 1, 2, 3, 4 and 5).
Basis:
There is sufficient time during the refueling mode (Mode 6) for an operator to assess plant status and respond to conditions without jeopardizing reactivity control or fission product boundary integrity.
ll.
Only systems and components which can affect (positive or negative impact) safe shutdown are subject to evaluation.
Basis:
Appendix R requires being able to achieve and maintain cold shutdown.
Any systems/components not impacting safe shutdown are not within the scope of this evaluation.
12.
Turbine trip does not necessarily result in an LOP condition.
Basis:
Given a turbine trip, it may be more conservative to assume that an LOP condition does not occur.
The turbine trip circuitry is subject to the single hot short, open circuit, or short to ground.
13.
No single (including common mode) failures in addition to the spurious action/inaction will be evaluated.
Basis:
Appendix R's scope does not consider any failures other than those caused by the fire.
14.
Evaluation drawings will be Bechtel-controlled project documents.
Examples are:
PAID's 13-M-XKP-XXX Elementaries 13-E-XKB-XXX Loop Diagrams 13-J-XXE-XXX One-Line Diagrams 13-E-XXA-XXX Controlled Vendor Prints FSAR Chapter 9 Appendix 9B Basis:
The identification of the control drawings defines the source material used for the evaluation and aids in traceability and reproducibility of results.
3146r PVNGS 02-NS-110 15.
Postulated fires in each FSAR Table 9B fire zone of the Auxiliary Building Control Building and Main Steam Support Structure will be evaluated for their impact on the ability to achieve SSD.
Basis:
The Turbine Building and Radwaste Building are excluded since no safety-related equipment is housed in these areas.
The Fuel Handling Building is excluded since it does not house safe shutdown components.
The Diesel Generator Building is excluded because it complies with Appendix R with no deviations.
The Containment Building is excluded because it is addressed by the deviation from
.the separation requirements of Appendix R for components and circuits located inside containment.
16.
Deleted.
17.
Simultaneous failures of both power supplies to one of the BOP ESFAS cabinets (FBEVAS,
- CRVIAS, DGSS, Load Sequencer
) cannot prevent the ability to achieve safe (cold) shutdown.
Basis:
Simultaneous failures of both power supplies to a
BOP ESFAS cabinet can result in activation of both trains of sequencer activated devices associated with FBEVAS,
This is not a
significant concern since actuation of these devices (essential chilled water, cooling water, spray pond, etc.)
has no negative impact on the ability to achieve safe shutdown.
NSSS components (LPSI, HPSI and containment spray pumps) will start only in the affected tr'ain but system operation will not occur (i.e., valves will not align) without simultaneous NSSS ESFAS present.
5.0 OUTSIDE CONTROL ROOM FIRE SPURIOUS ACTUATION EVALUATION LOGIC Figure NS-110-1 details the logic used in evaluating the outside control room fires.
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