ML20249C704
| ML20249C704 | |
| Person / Time | |
|---|---|
| Issue date: | 06/26/1998 |
| From: | Stewart Magruder NRC (Affiliation Not Assigned) |
| To: | Essig T NRC (Affiliation Not Assigned) |
| References | |
| PROJECT-689 NUDOCS 9807010065 | |
| Download: ML20249C704 (23) | |
Text
- _ _ _ - _ - _ _ _ _ _ _ _ - _ _ _ _ _ _ - _ _ -
l Jane 26','1998
)
MEMORANDUM TO: Thomas H. Essig, Acting Chief 4
Generic issues and Environmental Projects Branch Division of Reactor Program Management Office of Nuclear Reactor Regulation FROM:
Stewart L. Magruder, Project Manager Original Signed By:
Generic lasues and Environmental Projects Branch Division of Reactor Program Management Office of Nuclear Reactor Regulation
SUBJECT:
SUMMARY
OF JUNE 12,1998, MEETING WITH THE NUCLEAR ENERGY INSTITUTE (NEI) REGARDING SHUTDOWN EMERGENCY ACTION LEVELS On June 12,1998, representatives of the Nuclear Energy Institute (NEI) met with representatives of the Nuclear Regulatory Commission (NRC) at the NRC's offices in Rockville, Maryland. Attachment 1 provides a list of meeting attendees.
The purpose of the meeting was to discuss industry proposed guidance on emergency action levels (EALs) applicable in the shutdown and refueling modes of plant operation. Attachment 2 is the industry proposed guidance. The NRC expressed concems with the use of the barrier matrix as the format for the EALs. However, both the NRC and NEl representatives agreed 1
that the primary issue was the delineation of EALs that (1) cover the possible spectrum of l
events that could occur in the shutdown and refueling modes of plant operation and (2) result in licensees classifying these events at the appropriate level. To facilitate discussion of these EALs, the NRC distributed a list of EALs (not in a barrier matrix format) for each classification level vehich was developed from the proposed industry guidance (Attachment 3). A synopsis of the discussion of these EALs is included as Attachment 4. NEl stated that they would consider the NRC comments and plans were made to hold a telecon between the NRC and NEl to clarify I
any remaining issues prior to NEl resubmitting its EAL guidance.
The NRC commended NEl on its leadership in developing this EAL guidance and stated it would like to complete its efforts on the review and endorsement (if appropriate) of the NEl guidance by the end of 1998.
Project No. 689
/
Attachments: As stated cc w/att: See next page DISTRIBUTION: See attached page f
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't WASHINGTON, D.C. 20M0001 June 26, 1998 l
MEMORANDUM TO: Thomas H. Essig, Acting Chief Generic issues and Environmental Projects Branch Division of Reactor Program Management Office of Nuclear Reactor Regulation i
FROM:
Stewart L. Magruder, Project Manager My.%d Generic issues and Environmental Projects Branch y
Division of Reactor Program Management Office of Nuclear Reactor Regulation
SUBJECT:
SUMMARY
OF JUNE 12,1998, MEETING WITH THE NUCLEAR ENERGY INSTITUTE (NEl) REGARDING SHUTDOWN EMERGENCY ACTION LEVELS On June 12,1998, representatives of the Nuclear Energy institute (NEI) met with representatives of the Nuclear Regulatory Commission (NRC) at the NRC's offices in Rockville, Maryland. Attachment 1 provides alist of meeting attendees.
The purpose of the meeting was to discuss industry proposed guidance on emergency action levels (EALs) applicable in the shutdown and refueling modes of plant operation. Attachment 2 is the industry proposed guidance. The NRC expressed concems with the use of the barrier matrix as the format for the EALs. However, both the NRC and NEl representatives agreed that the primary issue was the delineation of EALs that (1) cover the possible spectrum of events that could occur in the shutdown and refueling modes of plant operation and (2) result I
in licensees classifying these events at the appropriate level. To facilitate discussion of these EALs, the NRC distributed a list of EALs (not in a barrier matrix format) for each classification level which was developed from the proposed industry guidance (Attachment 3). A synopsis of the discussion of these EALs is included as Attachment 4. NEl stated that they would consider the NRC comments and plans were made to hold a telecon between the NRC and NEl to clarify any remaining issues prior to NEl resubmitting its EAL guidance.
The.NRC commended NEl on its leadership in developing this EAL guidance and stated it would like to complete its efforts on the review and endorsement (if appropriate) of the NEl guidance by the end of 1998.
Project No. 689 Attachments: As stated 1
cc w/att: See next page 1
NRC/NEl MEETING ON SHUTDOWN EALs LIST OF ATTENDEES June 12,1998 NAME ORGANIZATION Alan Nelson NEl Bob Mandik PECO Nuclear Dave Stobough Commonwealth Edison Walter Lee Southern Nuclear Amir Afzali NUS LIS Barry Zalcman NRC/NRR Jim O'Brien NRC/NRR Warren Lyon NRC/NRR l
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2 3.
4.
1 2
Generic Basis Information For Recognition Category G 3
Cold Shutdow.1/ Refueling Barrier (Function) Degradation 4
5 INTRODUCTION 6
7 These EALs generally address the loss of barrier functions or specific fundamental indications as s
opposed to losses of particular equipment. In the context of these EALs, a barrier function is a 9
fundamental action that plant systems, structures, and components (SSCs) are required to perform.
10 Each of the barier functions is provided for in the plant design by particular SSCs, and in some cases, 11 there may be redundant and diverse SSCs provided for in the design.
12 13 In addition to the design SSCs, there may be other plant SSCs that could compensate for the loss of 14 tre design features, such that the barrier function could continue to be met. For the purpose of these 15 EALs, classifications are based on whether or not the barrier function can be, or is being, performed.
16 The design squipment qualification or technical specification operability status is irrelevant. The 17 classification emphasis is on performance, not on design or licensing commitment.
18 19 Detailed tabulations of SSC that are required to be unavailable for a barrier function to be considered 20 lost are not necessary. TM example EALs have been structured to provide a fundamental indication 21 which establishes the threshold for determining that the barrier function is lost. If the threshold is 22 exceeded, the combinations of SSC failures that led to the condition are irrelevant to the classification 23 process.
24 25 Section 3.14 of this document discusses the rational for these EALs, and is included in these bases 26 by reference. These bases will expand on those generic considerations. Some significant planning 27 assumptions addressed in the development of there EALs are:
28 29
- 1. There will be a wide variability of initial conditions for the events addressed herein due to different 30 plant c.; figurations that could occur during shutdown periods. During power operations, the 31 Fission Product Barrier Matrix classifies events on the loss or challenge to the fission product 32 barriers. During shutdown conditions, these baniers may have intentionally been defeated. For 33 this reason, these EALs are function and performance-based to the extent possible.
34 35 2, The redundancy and diversity of instruments typically used during power operations may be 36 unavailable during shutdown periods. For example, in BWRs, loss of forced flow through the 37 shutdown cooling, reactor recirculation, or reactor cleanup systems may result in the loss of 38 accurate reactor coolart temperature measurement. In some PWRs core exit thermocouple are 39 disconnected prior to removing the reactor vessel head. Loss of forced decay heat removal flow 40 may then render RCS loop or RHR inlet temperature instruments readings invalid. For this reason, 41 these EALs provide for alternative, site specific time-based EALs, in addition to the 42 instrumentation EALs.
43 44
- 3. The potential for core damage is directly related to the amount of decay heat available. Events 45 that occur eariier in shutdown will have the potential for greater consequence than will events that 46 occur later in shutdown. For this reason, these EALs provide thresholds based on temperature 47 increase. This threshold would be reached sooner for events that occur early in a shutdown than 48 those that occurlate in a shutdown.
5-C-2
T i
I 2
- 4. A false promise may be that " shutdown" means " safe". For some accident sequences, the core l
3 damage potential has been shown to be comparable to events that occur at power modes. The core damage potential is a function of the latent heat available and the capability of systems to 4
5 remove the heat. During shutdown evolutions redundancy of many system components may have 6
been intentionally decreased to facilitate maintenance therefore potentially increasing the 7
probabiirty that an event could lead to core damage.
i s
9
- 5. At 100% power, a 3000 Mwt reactor produces about 1E10 BTU /hr. Decay heat may represent as l
l 10 much as 0.1% reactor power at 30 days from shutdown. This corresponds to about 1E7 BTU /hr.
11 12
- 6. The radionuclides inventory in the core is approximately 0.6 Ci/ watt fotbwing extended operation at 13 power. Thus, at shutdown, the core inventory for a typical 3000 Mwt reactor may be as much as 14 1.8Eg Ci, of which more than 1.0E7 Ci is iodine. With the 8.3 day half-life of I-131, there is a 15 potential for significant radioactivity releases well into a shutdown period.
16 17
- 7. The format and specific wording of the example EALs is exper:ted to be modified to be compatible 18.
with individual utility nomenclature and procedure writing guidelines, provided that the intent of the 19 example EAL is maintained.
20 21 INITIATING CONDITIONS 22 23 The four initiating conditions classify the shutdown event on the basis of the Potential Loss or Loss of 24 one or more of the cold shutdown barrier functions.
25 26 Unusual Event (UE) 27 2s The Unusual Event is declared on the occurrence of a potential loss of t@g the RCS Barrier or the j
29 Fuel Clad Barrier. An Unusual Event declaration is deemed appropriate for a potential loss of either 30 the RCS Barrier or Fuel Clad Barrier as these conditions are considered to represent potential 31 degradation in the level of safety of the plant. This is consistent with the fundamental definition of an 32 Unusual Event.
33 34 Alert 35 36 The Alert is declared on the occurrence of a loss of the RCS Barrier. An Alert declaration is deemed 37 appropriate for a loss of the RCS Barrier as this condition is considered to represent substantial 3s degradation in the level of safety of the plant. This is consistent with the fundamental definition of an 39 Alert.
40 41 Site Area Emergency (SAE) 42 43 The SAE is declared on the occurrence of the loss of the RCS Banier and loss of Fuel Clad Barrier.
44 The basic definition of a SAE involves the actual or likely losses of plant functions needed for the 45 protection of the public. This IC represents a loss of two fission product barriers. The fact that this IC 46 calls for a SAE reflects the lower latent energy available to cause core melt. This is consistent with the 47 fundamental definition of an SAE.
5-C-3
1 General Emergensy (GE) 2 3
The GE is declared on the occurrence of the loss of function of att three baniers. If all three barriers 4
are lost, the ability to maintain fission product inventory within the containment no longer exists. This 5
mpresents a direct path for radioactive inventory to be released to the environment. This is consistent 6
with the definition of a GE.
7 I
l i
\\
5-C-4
TABLE 5 C 2 BWR Emergency Action Level I
Cold Shutdown i Refueling Barrist (Function) Degradation *
- Determine which combinebons of the three bemers era lost or have a potenhal kas and use the following key provided ort the metnx tab 6e to class #y the event.
UNUSUAL EVENT ALERT SITE AREA EMERGENCY GENERAL EMERGENCY Potental Loss of EITHER of the Laos of the RCS Bemer t oss of the RCS Bemer AND Fuel Loes of ALL three Bemers RCS Berner or Fuel Clod Berner C4ed Berner THRESHOLDS FOP. LOSS OR POTENTIAL LOSS OF BARRIERS Containment Barrier Example EALs LOSS POTENTIAL LOSS Pnmary Containment NOT Met.
Not Applicable AND EITHER
- 1) Secondary Containment NOT Met OR
- 2) ANY Secondary Containment { Site Specific}
Maximum Safe Radiation Level Exceeded RCS Barrier Example EALs LOSS POTENTIAL LOSS RPV Level Cannot Be Restored AND Maintained 2 UNPLANNED Event Resulting in RPV Level Decrease The { Site Specific} Low-Low ECCS Actuation Below The RPV Flange For115 minutes.
j Setpoint.
Fuel Clad Barrier Example EALs LOSS POTENTIAL LOSS RPV Level Cannot Be Restored AND Maintained 1 UNPLANNED Event Resulting in:
- { Site Specific) TOAF Level in s 30 minutes.
- 2) Exceeding the Calculated Time To Boll When { Site 1
Specific) RCS Temperature Indication Unavailable 5-C-5
1 Basis information For Table 5-C-2 2
BWR Emergency Action Level 3
Cold Shutdown / Refueling Barrier (Function) Degradation 4
5 FUEL CLAD BARRIER EXAMPLE EALs 6
l 7
These example EALs are based on concems raised by Generic Letter 88-17, Loss of Decay Heat l
s Removal, SECY 91-283, Evaluation of Shutdown and Low Power Risk issues, NUREG-1449, 9
Shutdown and Low-Power Operation at Commercial Nuclear Power Piants in the United States, and, 10 NUMARC 91-06, Guidelines for Industry Actions to Assess Shutdown Management. A number of 11 variables, such as initial vessellevel, or shutdown heat removal system design, can have a significant 12 impact on heat removal capability challenging the fuel clad barrier. Analysis in the above references 13 indicates that core damage may occur within an hour following continued core uncovery therefore, 14 conservatively,30 minutes was rf,st.en. The Loss example EAL represents the inability to restore and 15 maintain RPV level to above tw top of active fuel. Fuel damage is probable if RPV level cannot be 16 restored, as avkilable decay heat will cause boiling, further reducing the RPV level.
17 18 In the example EALs and the text below, reference is made to 200'F. This value was selected as 19 being the temperature at which the UNPLANNED heatup has forced a mode change, i.e., cold 20 shutdown to hot shutdown, as is typical at most BWRs. Facilities having a different temperature 21 criterion for mode change should substitute the site-specific value at each reference to 200*F.
22 l
5-C-6
I The Potential Loss addresses an UNPLANNED event resulting in loss of functions needed for cold 2
shutdown as evidenced by an increase in RCS temperature to greater than [200*F). The temperature increase does not, in of itself, warrant a declaration. However, an UNPLANNED event resulting in a 3
loss of functions needed for cold shutdown that is not corrected before the temperature exceeds 4
5
[200*F) forcing a mode change to Hot Shutdown, is considered to be a potential reduction in the level 6
of safety of the plant. Therefore this Potential Loss of Fuel Clad Barrier warrants a declaration of UE.
7 s
The (site specific) RCS temperature indication may vary in type and quantity but must monitor the temperature at the exit of the core / vessel. However, temperature indication that is dependent on 9
forced flow in the shutdown heat removal, recirculation, or reactor water cleanup systems for its 10 indication (e.g., shutdown heat removal system inlet temperature) may nct represent the temperature 11 la increase in the core during a loss of flow in most plant designs. Therefore, a (site specific) attemative 13 Time To Boll Caciculation could be provided, should the temperature instrumentation be unavailable.
14 in addition, if the RCS is intact, temperature can be inferred from RPV pressure once boiling 15 commences.
16 17 The Time To Boil Calculation is dependent on several initial conditions, including, but not limited to:
18 Time sface shutdown 19 30 Duration of power run prior to shutdown 21 22 Remaining heat removal flow 23 24 Number of fuel assemblies in reactor (e.g., full core, partial core offload) 25 26 Age of fuel assemblies in reactor (e.g., before or after core shuffle) 27 28 RPV inventory (e.g., normal, filled to flange, cavity flooded) 29 30 RCS temperature 31 32 RCS intact or open 33 30 Because of the large number of combinations possible, utilities may wish to identify the more limiting 35 36 combinations and provide table (s) or graph (s) of the time to reach the specified temperature for the 37 selected combinations. While these data might be more conveniently displayed as a series of graphs 38 of time to reach the specified temperature versus time since shutdown, a single time value 39 representing the most limiting case may be provided instead. However, this latter option may be unduly conscutive for many cases. In addition, graphs may enable response personnel to evaluate 40 41 whether or not the RCS can be made intact or the containment closure re-established prior to the 42 onset of boiling. Due to the large uncertainties, this attemative indication is applicable only when the 43 temperature instrumentation indication is unavailable, as stated above.
44 45 Many facilities perform these heatup calculations as part of shutdown risk management programs.
These calculations are typically performed as the plant configuration is changed. In lieu of providing 46 47 graphs or time estimates specif;c to these EALs, it would be appropriate to cross-reference the site-i 48 specific document that provides the current heatup data.
49 50 An UNPLANNED event with temperature indication unavailable which results in a loss of functions 51 needed for cold shutdown that is not corrected before the Time To Boil Calculation time is exceeded is 5-C-7
I considered 13 be a potential reduction in the level cf saf;ty of the pl:nt. Therefora this Potintill Loss 2
of Fuel Clad Barrier warrants a declaration of UE.
3 4
6 These example EALs serve as precursors to a loss of heat removal. The RCS Barrier Loss example 7
EAL represents a significant loss of RCS inventory. The magnitude of this loss of water indicates that s
makeup systems have not been effective and may not be capable of preventing further RPV level 9
decrease and potential core uncovery. This condition will result in a minimum classification of Alert.
10 The Low-Low ECCS Actuation Setpoint was chosen because it is a standard setpoint at which all 11 available injection systems automatically start. The inability to restore and maintain level after 12 reaching this setpoint would therfore be indicative of a failure of the RCS barrier.
13-14 The Potential Loss example EAL involves a decrease in RPV level below the top of the RPV flange 15 that continues for 15 minutes due to an unplanned event. Such a condition is a procursor to the loss 16 of the RCS Barrier and Fuel Clad Barrier and warrants a declaration of UE. This EAL is not applicable i
17 to decreases in flooded reactor cavity level (covered by AU2 EAL1) until such time as the level 18 decreases to the level of the vessel flange. If RPV level continues to decrease and reach the Low-Low 19 ECCS Actuation Setpoint then a Loss is considered to exist.
20 21 EAL modifiers such as " UNPLANNED" or "for X minutes" are used since the continuing loss of level 22 indicates the lack of a success path to restore inventory.
23 24 CONTAINMENT BARRIER EXAMPLE EALs 25 26 in the context of these EALs," containment closure"is the action taken to secure primary or secondary 27 containment and its associated structures, systems, and components as a funcbonal barrier to fission 28 product release under existing plant conditions. If primary containment is not met then either 29 secondary containment must be met or the Secondary Containment radiation level must be verified 30 less than the Maximum Safe Radiation Level to allow the Containment Barrier to be considered intact.
31 32 The Maximum Safe Radiation Level being exceeded may preclude actions underway to reestablish j
33 Primary or Secondary closure and may be indicative of a release from Primary to Secondary 34 Containment. Site shutdown contingency plans typically provide for re-establisher g containment l
35 closure following a loss of heat removat or RCS inventory functions. If the closure is re-established i
36 prior to exceeding the temperature orlevel thresholds of the RCS Barrier and Fuel Clad Barrier EALs, 37 escalation to GE would not occur.
i 38 39 Since this example EAL can only lead to a GE classification in conjunction with. Loss of RCS Barrier 40 and fuel Clad Banier, no time duration for loss of closure is specified 41 42 No potential loss example EAL is provided.
43 i
44 l
1
)
i 5-C-8
1
,2 TABLE S C 3 3
PWR Emergency Action Level 4
Cold Shutdswa / Refueling Barrier (Function) Degradation
- 5 6
'Delemene which osmbmobone of the twee bentare are lost er have e potenhet lose and une the fogowin0 hoy provided on the motnx table to closelfy the 7
event.
8 UNUSUAL EVENT ALERT StTE AREA EMERGENCY GENERAL EMERGENCY PotenbelLees of EITHER of the Lees of the RCs Bemer Loss of the RCs Gamer AND Fuel Laos of ALLewee Bemers CCs Borner er Fuel cand tenter Cted Benter 9
10.
THRESHOLDS FOR LOSS OR POTENTIAL LOSS OF BARRIERS Containment Barrier Example EALs LOSS POTENTIAL LOSS Containment Closure NOT Established Not Applicable RCS Barrier Example EALs LOSS POTENTIAL LOSS RCS Level Cannot be Restored and Maintained 2 UNPLANNED Event Resulting RCS Level Decrease the { Site Specific) Bottom (ID) of the RCS loop.
below the Reactor Vessel Flange for115 minutes.
Fuel Clad Barrier Example EALs LOSS POTENTIAL LOSS R ' ctor Vessel Level Cannot Be Restored AND UNPLANNED Event Resulting in:
e Maintained 2 (Site Specific) TOAF Level in 5 30
- 1) { Site Specific) RCS Temperature Exoseding 200*F minutes.
- 2) Exceeding the Calculated Time To Boil When { Site Specific) RCS Temperature indication Unavailable l
i j
i 5-C-9 a
4
Basis information For Table 5-C-3 PWR Emergency Action Level Cold Shutdown / Refuellag Barrier (Function) Degradation FUEL CLAD BARRIER EXAMPLE EALs These example EALs are based on concems raised by Generic Letter 88-17, Loss of Decay Heat Removal, SECY 91-283, Evaluation of Shutdown and Low Power Risk issues, NUREG-1449, Shutdown and Low-Power Operation at Commercial Nuclear Power Plants in the United States, and, NUMARC 91-06, Guidelines for Industry Actions to Assess Shutdown Management. A number of variables, such as initial vessel level (e.g., mid-loop, reduced level / flange level, head in place, or cavity flooded, RCS venting strategy, decay heat removal system design, vortexing pre-disposition, steam generator U-tube draining) can have a significant impact on heat removal capability thus challenging the fuel clad barrier. Analysis in the above references indicates that core damage may occur within an hour following continued core uncovery therefore, conservatively,30 minutes was chosen. The Loss example EAL represents the inability to restore and maintain RCS level to above the top of active fuel. Fuel damage is probable if RCS level cannot be restored, as available decay heat will cause boiling, further reducing the RCS level.
In the example EALs and the text below, reference is made to 200'F. This value was selected as being the temperature at which the UNPLANNED heatup has forced a mode change, i.e., cold shutdown to hot shutdown, as is typical at most PWRs.
Facilities having a different temperature criterion for mode change should substitute the site specific value at each reference to 200'F.
5-C-10
The Potential Loss addresses an UNPLANNED event resulting in loss of functions needed for cold shutdown as evidenced by an increase in RCS temperature to greater than [200*F]. The temperature increase does not, in of itself, warrant a declaration.
However, an UNPLANNED event resulting in a loss of functions rieeded for cold shutdoivn that is not corrected before the temperature exceeds [200*F] forcing a mode change to Hot Shutdown, is considered to be a potential reduction in the level of safety of the plant. Therefore this Potential Loss of Fuel Clad Barrier warrants a declaration of i
UE.
The (site specific) RCS temperature indication may vary in type and quantity but must monitor the temperature at the exit of the core / vessel. However, temperature indication that is dependent on forced flow may not represent the temperature increase in the core during a loss of flow in most plant designs. Therefore, a (site specific) attemative Time To Boil Caciculation could be provided, should the tempera! a instrumentation be unavailable. In addition, if the RCS is intact, temperature can oe inferred from RCS pressure once boiling commences.
The Time To Boil Calculation is dependent on several initial conditions, including, but not limited to:
Time since shutdown Duration of power run prior to shutdown e
Remaining heat removal flow e
Number of fuel assemblies in reactor (e.g., full core, partial core offload) e Age of fuel assemblies in reactor (e.g., before or after core shuNie)
RCS inventory (e.g., normal, filled to flange, cavity flooded) e RCS temperature e
RCS intact or open e
Because of the lars a number of combinations possible, utilities may wish to identify the more limiting combinations and provide table (s) or graph (s) of the time to reach the specified temperature for the selected combinations. While these data might be more conveniently displayed as a series of graphs of time to reach the specified temperature versus time since shutdown, a single time value representing the most limiting case may be provided instead. However, this latter option may be unduly conservative for many cases. In addition, graphs may enable response personnel to evaluate whether or not the RCS can be made intact or the containment closure re-established prior to the onset of boiling. Due to the !arge uncertainties, this attemative indication !s applicable only when the temperature instrumentation indication is unavailable, as stated above.
5-C-11
_-.m_
Many facilities perform these heatup calculations as part of shutdown risk management programs. These calculations are typically perfomled as the plant configuration is changed. In lieu of providing graphs or time estimates specific to these EALs, it would be appropriate to cross-reference the site-specific document that provides the current heatup data.
I An UNPLANNED event with temperature indication unavailable which results in a loss of functions needed for cold shutdown that is not corrected before the Time To Boil Calculation time is exceeded is considered to be a potential reduction in the level of safety of the plant. Therefore this Potential Loss of Fuel Clad Barrier warrants a declaration of UE.
RCS BARRIER EXAMPLE EALs These example EALs serve as precursors to a loss of heat removal. The RCS Barrier Loss example EAL represents a significant loss of RCS inventory. The magnitude of this loss of water indicates that makeup systems have not been effective and may not be capable of preventing further RCS level decrease and potential core uncovery. This condition will result in a minimum classification of Alert. The Bottom ID of the RCS Loop Setpoint was chosen because at this level remote RCS level indication may be lost and loss of suction to decay heat removal systems may occur. Inability to restore and maintain level above the Bottom ID of the RCS Loop may therefore be indicative of a failure of the RCS barrier.
The Potential Loss example EAL involves a decrease in RCS level below the top of the Reactor Vessel flange that continues for 15 minutes due to an unplanned event. Such a condition is a precursor to the loss of the RCS Barrier and Fuel Clad Barrier and warrants a declaration of UE. This EAL is not applicable to decreases in flooded reactor cavity level (covered by AU2 EAL1) until such time as the level decreases to the level of the Reactor Vessel flange. If RCS level continues to decrease and reachs the the Bottom ID of the RCS Loop then a Loss is considered to exist.
EAL modifiers such as " UNPLANNED
- or "for X minutes" are used since the continuing loss of level indicates the lack of a success path to restore RCS inventory.
CONTAINMENT BARRIER EXAMPLE EALs In' the context of this EAL, " containment closure" is the action taken to secure containment and its associated structures, systems, and components as a functional barrier to fission product release under existing plant conditions. Containment closure should not be confused with refuelin0 containment integrity as defined in technical specifications. Site shutdown contingency plans typically provide for re-establishing containment closure following a loss of heat removal or RCS inventory functions, if the closure is re-established prior to exceeding the temperature or level thresholds of the RCS Barrier and Fuel Clad Barrier EALs, escalation to GE would not occur.
Since this example EAL can only lead to a GE classification in conjunction with Loss of RCS Barrier and Fuel Clad Barrier, no time duration for loss of closure is specified.
5-C-12
4
- No potentialloss example EAL is provided.
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5-C-13
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UNUSUAL EVENT IC:
UNPLANNED Loss of Decay Heat Removal Event EAL:
1 1.
Uncontrolled RCS Temperature rise greater than 20 *F OR 2
(Site Specific} RCS Temperature Exceeding 200*F OR 3
Exceeding the Calculated Time To Boil When (Site Specific} RCS Temperature Indication Unavailable IC:
UNPLANNED Loss of RCS Inventory Event
, EAL:
1.
RPV Level Decrease Below The RPV Flange For 215 minutes (when RPV level initially above the RPV flange).
i OR
~
2.
RPV level decrease of { site-specific value} and RPV 1evel decrease not terminated within 15 minutes (when RPV level initially below the RPV flange) i i
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ALERT IC:
Prolonged Loss of Decay Heat Removal l
EAL:
Ia.
(Site Specific) RCS Temperature Exceeding 200*F OR lb.
Exceeding the Calculated Time To Boil When (Site Specific) RCS Temperature Indication Unavailable AND 2.
Time to recover heat removal capacity has (or is expected to) exceed 30 minutes IC: Loss of RCS inventory which affects decay heat removal capability EAL:
l.
RP" level less than (site-specific) low-low ECCS actuation setpoint (BWR) 1.
RCS level less than bottom ID of the RCS loop (PWR)
OR 2.
< site-specific > indication of a significant loss of vessel inventory with inability to monitor vessel water level l
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SITE AREA EMERGENCY IC: Prolonged Loss of Decay Heat Removal with containment integrity not established EAL:
l la.
(Site Specific} RCS Temperature Exceeding 200*F OR l b.
Exceeding the Calculated Time To Boil When { Site Specific} RCS Temperature Indication Unavailable AND 2.
Time to recover heat removal capacity has (or is expected to) exceed 30 minutes AND 3.
CONTAINMENT CLOSURE NOT established IC Loss of RCS inventory which affects decay heat removal capability with Containment 1
Integrity not intact EAL: [l or 2] and 3 1.
RPV levelless than { site-specific} low-low ECCS actuation setpoint (BWR) 1.
RCS level less than bottom ID of the RCS loop (PWR)
OR 2.
< site-specific > indication of a loss of vessel inventory (of greater than < site-specific value> with inability to monitor vessel water level AND 3.
CONTAINMENT CLOSURE NOT established IC: Loss of RCS inventory which affects fuel clad integrity EAL:
1.
RPV level less than TAF for > (site-specific minutes}
OR 2.
< site-specific > indication of c loss of vessel inventory which may uncover fuel with inability to monitor vessel water level
+
GENERAL EMERGENCY IC: Potential Fuel Damage with RCS and containment not intact EAL:
Ia.
RCS level below TAF for greater than (site specific minutes)
OR lb.
< site-specific > indication of a loss of vessel inventory which may uncover fuel with inability to monitor vessel water level OR Ic.
- Area radiation monitors exceed site-specific values AND 2.~
- CONTAINMENT CLOSURE NOT established i
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Synopsis of Discussion of Shutdown EALs l
l A synopsis of the discussion on each of the EALs shown in Attachment 3 is described below.
l.
IC:
UNPLANNED Loss of Decay Heat Removal NEl stated that it had reconsidered the appropriateness of specifying a given RCS temperature rise as an EAL in addition, discussions wer6 held regarding the need for consistency between the setpoints for EAL #1 and #2.
II.
IC:
UNPLANNED Loss of RCS Inventory Discussion on this EAL focused on the need to ensure that the unplanned nature of the event was captured in the EAL and the need for an additional EAL covering the situation where there is a loss ofindication.
Ill.
IC:
Prolonged Loss of Decay Heat Removal Discussions were held regarding whether this IC and EAL was more appropriately classified as
.an Unusual Event or Alert.
IV.
IC:
Loss of RCS inventory which affects decay heat removal capability Concems were discussed regarding what constitutes a "significant" loss of vessel inventory V.
IC:
Loss of RCS inventory which affects decay heat removal capability IC:
Loss of RCS inventory which affects decay heat removal capability with Containment integrity not intact Concems were raised that the EALs are not indicative of a Site Area Emergency and, therefore, should not be included as shutdown EALs.
VI.
IC:
Loss of RCS inventory which affects fuel clad integrity 4
No concerns were identified with this EAL.
Vll.
IC:
Potential Fuel Damage with RCS and containment not intact Concerns were expressed regarding the use of the term " potential" in the IC. NEl believed that
" imminent" would better describe the plant condition of concern. Industry representatives stated that EAL #1c was reot appropriate for PWRs.
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6-Nuclear Energy Institute Project No. 689 cc:
Mr. Ralph Beedle Ms. Lynnette Hendricks, Director Senior Vice President Plant Support and Chief Nuclear Officer Nuclear Energy Institute Nuclear Energy Institute Suite 400 Suite 400 :
17761 Street, NW 1776 l Street, NW Washington, DC 20006-3708 Washington, DC 20006-3708 Mr. Alex Marion, Director Programs Nuclear Energy Institute Suite 400 1776 l Street, NW Washington, DC 20006-3708 Mr. David Modeen, Director Engineering _
Nuclear Energy Institute Suite 400
' 1776 i Street, NW Washington, DC 20006-3708 Mr. Anthony Pietrangelo, Director Licensing Nuclear Energy Institute Suite 400 1776 i Street, NW Washington, DC 20006-3708 Mr. Nicholas J. Liparulo, Manager Nuclear Safety and Regulatory Activities Nuclear and Advanced Technology Division Westinghouse Electric Corporation P.O. Box 355 Pittsburgh, Pennsylvania 15230 Mr. Jim Davis, Director Operations -
Nuclear Energy Institute Suite 400 l.
1776 l Street, NW l
Washington, DC 20006-3708 I
r
q Distribution: Mtg. Summary w/ NEl Re Shutdown EALs Dated June 26, 1998 HariCopy Docket File PUBLIC PGEB R/F OGC ACRS SMagruder JO'Brien EMail SCollins/FMiraglia BSheron BBoger JRoe DMatthews TE:sig CMiller FAkstulewicz BZaleman JO'Brien EFox FKantor DBarss LCohen GTracy, EDO
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