ML17158B699
| ML17158B699 | |
| Person / Time | |
|---|---|
| Site: | Susquehanna  |
| Issue date: | 07/01/1996 |
| From: | Poslusny C NRC (Affiliation Not Assigned) |
| To: | Byram R PENNSYLVANIA POWER & LIGHT CO. |
| References | |
| TAC-M85668, TAC-M85669, NUDOCS 9607030124 | |
| Download: ML17158B699 (29) | |
Text
Hr. Robert G.
Byram Senior Vice President-Nuclear Pennsylvania Power and Light Company 2 North Ninth Street Allentown, PA 18101 July i, 1996
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION CONCERNING SUSQUEHANNA STEAM ELECTRIC STATION, UNITS 1
AND 2, PROPOSED EMERGENCY ACTION LEVELS (TAC NOS.
H85668
& H85669)
Dear Hr. Byram:
In letters dated January 5,
1994 and October 2,
- 1995, Pennsylvania Power
& Light (PP&L) Company responded to concerns which the staff identified concerning the Susquehanna Steam Electric Station's emergency action level (EAL) revision to the NUMARC methodology.
We have completed our review of the PP&L responses and have identified several issues which remain to be resolved before the staff can approve the EAL revision.
We request that PP&L provide additional information as discussed in the enclosed request for additional information (RAI) to support resolution of the remaining issues by November 1,
1996.
Sincerely, Original signed by:
Chester
- Poslusny, Senior Project Manager Project Directorate I-2 Division of Reactor Projects I/II Office of Nuclear Reactor Regulation
,-Docket.F.i 1 e.-'UBLIC PDI-2 Reading SVarga CHiller JO'Brian JZwol inks i JStol z HO'Brien OGC Docket Nos.
50-387/388
Enclosure:
Susquehanna EAL Review cc w/encl:
See next page DISTR I BUTION:
- WPasciak, RGN-I CPoslusny j3Fo I /g OFFICE P
NAME DATE
/
96 PDI-2/PH CPoslusny:mw
/
/96 PDI-2/D Jstol z
/
/96 OFFICIAL ECORD COPY DOCUMENT NAME:
SUH85668.RAI ns0039
'Ph07030124
'76070K PDR ADQCK 050003S7 F
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 July 1, 1996 Mr. Robert G.
Byram Senior Vice President-Nuclear Pennsylvania Power and Light Company 2 North Ninth Street Allentown, PA 18101
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION CONCERNING SUSQUEHANNA STEAM ELECTRIC STATION, UNITS 1
AND 2, PROPOSED EMERGENCY ACTION LEVELS (TAC NOS.
M85668 & M85669)
Dear Mr. Byram:
In letters dated January 5,
1994 and October 2,
- 1995, Pennsylvania Power
& Light (PP&L) Company responded to concerns which the staff identified concerning the Susquehanna Steam Electric Station's emergency action level (EAL) revision to the NUHARC methodology.
We have completed our review of the PP&L responses and have identified several issues which remain to be resolved before the staff can approve the EAL revision.
We request that PP&L provide.
additional information as discussed in the enclosed request for additional information (RAI) to support resolution of the remaining issues by November 1,
1996.
Sincerely, Q~. Pm/
Chester
- Poslusny, Senior Project Manager Project Directorate I-2 Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation Docket Nos. 50-387/388
Enclosure:
Susquehanna EAL Review cc w/encl:
See next page
r
Mr. Robert G.
Byram Pennsylvania Power
& Light Company Susquehanna Steam Electric Station, Units 1
& 2 CC:
Jay Silberg, Esq.
- Shaw, Pittman, Potts
& Trowbridge 2300 N Street N.W.
Washington, D.C.
20037 Bryan A. Snapp, Esq.
Assistant Corporate Counsel Pennsylvania Power
& Light Company 2 North Ninth Street Allentown, Pennsylvania 18101 Mr. J.
M. Kenny Licensing Group Supervisor Pennsylvania Power
& Light Company 2 North Ninth Street Allentown, Pennsylvania 18101 Mrs. Maitri Banerjee Senior Resident Inspector U. S. Nuclear Regulatory Commission P.O.
Box 35 Berwick, Pennsylvania 18603-0035 Mr. William P. Dornsife, Director Bureau of Radiation Protection Pennsylvania Department of Environmental Resources P. 0.
Box 8469 Harrisburg, Pennsylvania 17105-8469 Mr. Jesse C. Tilton, III Allegheny Elec. Cooperative, Inc.
212 Locust Street P.O.
Box 1266 Harrisburg, Pennsylvania 17108-1266 Regional Administrator, Region I U.S. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, Pennsylvania 19406 Mr. Harold G. Stanley Vice President-Nuclear Operations Susquehanna Steam Electric Station Pennsylvania Power and Light Company Box 467 Berwick, Pennsylvania 18603 Mr. Herbert D. Woodeshick Special Office of the President Pennsylvania Power and Light Company Rural Route 1,
Box 1797 Berwick, Pennsylvania 18603 George T. Jones Vice President-Nuclear Engineering Pennsylvania Power and Light Company 2 North Ninth Street Allentown, Pennsylvania 18101 Dr. Judith Johnsrud National Energy Committee Sierra Club 433 Orlando Avenue State College, PA 16803 Chairman Board of Supervisors 738 East Third Street
- Berwick, PA 18603
SUPPLEMENTAL RE UEST FOR ADDITIONAL INFORMATION SUS UE ANNA STEAN ELECTRIC STATION NUCLEAR PLANT UNITS 1
AND 2 EAL REVISIONS TO NUMARC NESP-007 METHODOLOGY Th
'Nucl ar Regulatory Commission (NRC) completed a review of the additional information transmitted in the January 5,
1994 and October 2,
- 1995, Susquehanna Steam Electric Station (SSES),
Units 1 and 2, emergency action level (EAL) submittals.
The additional information was requested following the initial NRC review of the SSES January 21,
1994.
The proposed EALs and additional information submitted were reviewed against the guidance in NUMARC/NESP-007, "Methodology for Development of Emergency Action Levels," Revision 2 (January, 1992).
NUMARC/NESP-007 has been endorsed by the NRC in Regulatory Guide 1.101, "Emergency Planning and Preparedness for Nuclear Power Reactors,"
Revision 3, as an alternative means by which licensees can meet the requirements in 10 CFR 50.47(b)(4) and Appendix E to 10 CFR Part 50.
Since the staff has previously endorsed the guidance in NUMARC/NESP-007, the review focused on those EALs that deviated from the guidance.
The additional information submitted and the procedure/plan review resolved many of the staff'.s questions.
- However, many areas of concerns remain with specific EALs which require further information and review.
Please provide this additional information as discussed below.
General:
Lack of Initiating Conditions The SSES EAL scheme does not follow the NUMARC methodology of grouping EALs under initiating conditions (ICs).
In the October 2, 1995 submittal, the licensee stated that they developed a classification matrix to include the ICs in each EAL.
However, the addition of the ICs to the matrix added confusion on what was the actual classification parameter.
As stated in the NUMARC guidance, an EAL is "a pre-determined, site-specific, observable threshold for a plant Initiating Condition that places the plant in a given emergency class."
The NUMARC scheme groups EALs under the IC to which the-EALs correspond.
This allows the person classifying (and the people being notified of the classification) to understand the plant condition of concern.
The EALs, by themselves, in many cases do not provide an easily recognizable connection to the plant concern.
For instance, the SSES EAL scheme includes an Alert level EAL for area radiation monitor exceeding a given value.
The IC which this EAL applies to is radiation levels which impede operation of safety equipment.
Without including the IC with the EAL, it is not readily apparent to users of the EAL what the EAL is indicating.
This may result in confusion
to the users of the EAL.
In addition, not including ICs restricts the use of judgement in deciding whether a plant condition warrants a classification.
For instance in the example just stated, if radiation levels were elevated to the extent that access to safety equipment was restricted but an area radiation monitor was not located in that area or was inoperable, the event should be classified as an Alert based upon recognition by the emergency director of the plant condition.
Having the EAL without ICs would make this judgement difficult.
It is not acceptable to have EALs which are not,grouped under ICs.
It is possible to group the'EALs under ICs without adding confusion to the classification process.
The NUMARC guidance provides an example of how this can be accomplished.
Please revise the EALs to be consistent with the NUMARC guidance or provide additional justification for this deviation.
EAL 1.1.1.a Chemistry determines that reactor coolant activity exceeds technical specification limits.
This SSES EAL deviates from NUMARC EAL SU4-1 in that mode 5 is not included as an applicable mode.
SSES justification for this deviation is that, because the technical specification is.not applicable in mode 5, the 'EAL should not be applicable in mode 5 and that it might be confusing to operators.
- However, the basis of the EAL is not that the technical specification has been exceeded.
- Rather, the basis is that the plant condition is'uch that there is a potential degradation in the safety of the plant which warrants an Unusual Event classification.
The technical specification setpoint is used as the threshold for this EAL because it is a readily observable indication of the plant condition of concern.
The basis for this EAL should address this issue
'o that users of the classification procedure will not be confused as to why this EAL is applicable in mode 5.
Please revise this EAL to be consistent with the NUMARC guidance or provide additional justification for this deviation.
EAL 2.1.4.a Reactor Pressure Vessel Water level below the Top of Active fuel for greater than 15 minutes This SSES EAL corresponds to the NUMARC EAL "reactor vessel water level LESS THAN (site-specific) value and the maximum core uncovery time limit is in the unsafe region."
The SSES EAL technical basis document states that: "Fifteen minutes was chosen as a limiting time because it indicates that ECCS system has been unsuccessful in reflooding the, core.
In addition, a plant specific analysis shows that fuel clad damage occurs within 15 minutes assuming that the core
.is totally uncovered....
Fifteen minutes with water level below the
top of active fuel represents an early indicator that significant core damage is in progress while providing sufficient time to initiate public protective actions."
The maximum core uncovery core time limit curve"provided in the emergency operating procedures (EOPs) indicates the maximum time that a core can be completely uncovered without core peak clad temperature exceeding 1500 'F.
It is not clear how the EOP curve relates to the SSES setpoint.
Please provide a copy of the EOP curve for the maximum core uncovery time limit so that the relationship between the SSES EAL'setpoint, i.e. exceeding 15 minutes, and the NUHARC EAL setpoint, and i.e. exceeding the maximum core uncovery time, can be determined.
EAL 2. 1.3.b Reactor Pressure Vessel Water Level Cannot be Determined This SSES EAL does not correspond to any of the NUHARC EALs.
SSES contends that this EAL is indicative of the condition where the loss of water level in the reactor vessel has or will uncover fuel in the reactor vessel or the condition of the loss of both the fuel clad and reactor coolant boundary.
Further justification is needed to assure that this EAL will not result in a Site Area Emergency classification when such a classification is not warranted.
For example, in accordance with this EAL, an event where the vessel level indicators were lost due to instrument failure while in cold shutdown would result in a Site Area Emergency'classification.
This would be inappropriate without further indication of level control problems.
This condition may be more appropriately addressed under the loss of assessment capability EALs.
Please provide further justification for this EAL.
This comment also applies to EAL 2.1.4.b EAL 2.2.3 A full,reactor scram has been initiated with failure of both automatic and manual trips to bring the reactor sub-critical and Suppression pool temperature
> 110 'F and Reactor power > 5X This EAL deviates from the NUHARC EAL by including conditions on reactor power level and suppression pool temperature.
The staff is concerned that adding these conditions will result in delaying classification of the event. If the conditions were logically connected with an "or"'instead of "and," i.e, suppression pool temperature
> 110 F or Reactor power > 5X, then the EAL would be acceptable if documentation is provided which shows that the suppression pool will not rapidly heat up at 5N reactor power with or without suppression pool cooling upon closure of the HSIVs.
Please revise this EAL to be consistent with the NUHARC guidance or provide additional justification for this deviation.
EAL 2.2.4 A full reactor scram has been initiated with failure of both automatic and manual trips to, bring the reactor sub-critical, and Suppression pool temperature
> 200 'F, and Reactor power
> 5X The corresponding NUMARC EAL is "(Site-specific) indications exist that automatic and manual scram were not successful AND (Site-specific) indications exist that the core cooling is extremely challenged OR (Site-specific) indication exists that heat removal is extremely challenged.,"
SSES states that the suppres'sion pool temperature greater than 200 'F is used as an indication that core cooling is extremely challenged.
The suppression pool temperature is more fittingly considered as an indication that heat removal is extremely challenged.
A more appropriate indication for the challenge to core cooling would be reactor water level at or below the top of active fuel.
Furthermore, although the suppression pool temperature may be an indication that heat removal is extremely challenged, the indication that the suppression pool temperature'xceeds the Heat Capacity Temperature Limit seems to be a more appropriate condition for this EAL.
In addition, including a
power level for this EAL deviates from the NUMARC guidance and has not been adequately justified.
The staff is concerned that if core cooling or heat removal is extremely challenged and the reactor is not fully shutdown it may be difficult to accurately determine current reactor.
power (i.e. if vessel level is below top of active fuel) or reactor power may increase due to changing plant conditions (e.g.
emergency depressurization with subsequent core reflood inserting cold, unborated water).
Please revise this EAL to be consistent with the NUMARC guidance or provide additional justification for this deviation.
EAL 3.1.2 Drywell Pressure indication
> 3.psig The SSES EAL deviates from the NUMARC EAL by setting the threshold for this EAL at 3 psig instead of at the drywell pressure alarm setpoint.
In response to the NRC concern on this setpoint, SSES performed a calculation which showed that a drywell pressure of 3 psig would be reached in about 70 minutes for a water leak of 50 gpm into containment.
A drywell pressure of 1.72 psig (reactor scram setpoint) would be reached in about ll minutes.
It is not appropriate to wait for over one hour to determine if the threshold for the Alert declaration (i.e.
a 50 gpm leak) has been exceeded. It is more appropriate to use the drywell pressure trip setpoint of 1.72 psig.
Note that the NUMARC guidance states that the drywell alarm setpoint should be used and not the drywell trip setpoint.
- However, SSES has shown the drywell pressure trip.setpoint would be reached in a short period of time for the 50 gpm leak, and use of the drywell pressure trip setpoint is justified.
Please revise this EAL to be consistent with the NUMARC guidance or provide additional justification for this devi,ation.
i v
teL 5.l.l.o Abnormal gaseous release for greater than 60 minutes which exceeds 2 times technical specifications as indicated by sample analysis Noble gases 1 rem/yr (total body)
I-131, Tritium, and Particulates with half-lives greater than 8 days
> 3 rem/yr (any Organ) inhalation pathways only Please explain why the term "abnormal" is included in this EAL since by definition a release exceeding technical specification limits would be abnormal.
SSES did not include the note included in the corresponding NUHARC EAL, i.e.
"ifmonitor reading(s) is sustained and the required assessment cannot be completed within this period, then. the declaration must be made based on the valid reading."
This note is intended to allow for the confirmation of the magnitude of the release relative to the ODCH release threshold and to prompt dose assessment using real-time meteorology to assess whether the Site Area Emergency or General Emergency EAL may be exceeded due to adverse weather conditions.
Please explain why this note was not included in the SSES EAL scheme.
In addition, indicate whether the FSAR source term used to derive the release setpoint is based on normal releases or accident releases.
I EAL 5.4.2.a Valid unplanned area radiation monitor readings indicate:
Control Room (ARH 39)
> 15 Hr/hr Please explain why the term "unplanned" is included in this EAL.
This EAL is based upon radiation levels which impede operation of systems required to maintain safe operations.
If safe operation of the plant is impeded due to radiation levels, the event should be classified as an Alert even if the event was planned.
It seems improbable that events would be planned which would result in radiation levels which would impede safe operation.
Please remove term "unplanned" from this EAL or provide further justification for including it in the EAL.
This comment also applies to EAL 5.4.2.b.
NUHARC EAL ASl-4 Field Survey results indicate site boundary dose rates exceeding 100 Hr/hr expected to continue for more than one hour; or analyses of field survey samples indicate child thyroid dose commitment of 500 Hr for one hour of inhalation The SSES EAL scheme did not include an EAL corresponding to this NUHARC EAL.
SSES states that, "Field survey results are used for classification'if the SPING data is not available.
Therefore, this EAL does take into account the" field survey results when the parameters were established."
It is not clear
what parameters use the field survey results.
The field survey results provide an accurate assessment of the pot'ential dose consequence to the public and should be included as an EAL.
This comment also applies ta NUMARC EAL AG1-4.
Please revise this EAL to be 'consistent with the NUMARC guidance or provide additional justification for this deviation.
EAL 6. 1.2.b Loss of Power from Startup Transformer 10 or 20 tu either unit and onsite AC Power is not available It is not clear what the term "onsite AC Power is not available." corresponds to in this EAL.
The basis for this EAL indicates that the condition "onsite AC Power is not available" corresponds to the loss of all four emergency diesels.
However, it seems that this EAL may be difficult to implement without referring to the EAL basis.
- Please, revise this EAL to make it more explicit or justify how users of the EAL will be able to implement this EAL without error or delay in classification.
EAL 6.1..a Loss of power from Startup transformers 10 and. 20 to either unit and All 4. 16 KV ESS Buses on either unit are de-energized
(>2 hours)
This SSES EAL deviates from the NUMARC guidance by including the condition that offsite power is lost for > 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> instead of the NUMARC condition that "Restoration of at least one emergency bus within (site-specific) hours is NOT likely."
As stated in the NUMARC basis, "This IC is specified to assure that in the unlikely event of a prolonged station blackout, timely recognition of the seriousness of the event occurs and that declaration of a General Emergency occurs as early as is appropriate based on a reasonable assessment of the event trajectory."
As written, the SSES EAL would not result in a General Emergency declaration until 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> after the Station BI'ackout occurred even if it was determined early on in the event that power to the emergency busses could not be restored.
Please revise this EAL to be consistent with the NUMARC guidance or provide.
additional justification for this deviation.
EAL 6. 1.4.b Loss of power from Startup transformers 10 and 20 to either unit (>2 hours) and All 4. 16 KV ESS Buses on either unit are de-energized, and any parameter in Table 6.1, Indications of Fuel Barrier Degradation, has been exceeded
Thi" S"E~
EAL "
~'t s from the NUMARC guidance by including the condition that offsite power is lost for > 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> s in conjunction with indication of fuel clad barrier degradation.
It is not appropriate to wait to declare a General Emergency if a station blackout has occurred and there is indication of fuel clad degradation.
Therefore, the condition that the loss of offsite power must be longer than 2
hours in duration should be removed from this EAL.
Please revise this EAL to be consistent with the NUHARC guidance or provide additional justification for this deviation.
EAL 7.3.2.
Uncontrolled reactor coolant temperature increase
(> 200 'F) and Suppression Pool Temperature
(>120 'F)
OR Suppression Pool Level
< 12 ft In our June 9,
1993 RAI, we identified a concern that this EAL did not contain sufficient indications for the condition of the loss of technical specification required functions to maintain cold shutdown.
In your January 5,
1994 response, you provided justification for this EAL stating that the technical specification allows alternative methods to be used to remove deca'y heat and that listing of these systems adds complexity.
The loss of all RHR and the inability to restore RHR or an alternative heat removal method prior to exceeding 200 'F is an indication of a loss of the heat removal function and therefore is indicative of an "Alert." It is not acceptable to use suppression pool parameters to indicate the loss of heat removal capability because there may be events where the suppression pool may be unavailable, e.g. in the refueling mode of operation, and even if the sUppression poul were available, the reactor would have to pressurize before the SRVs can be used to remove decay heat.
Please modify this EAL to conform with the NUHARC guidance or provide additional information which justifies the appropriateness of this EAL.
EAL 7.3.3 Loss of all systems'eeded to achieve cold shutdown and suppression pool temperature
> 200 F or, suppression pool level
< 12 feet The SSES technical basis document does not provide justification for the chosen suppression pool parameters.
It appears that EOP conditions such as reaching the heat capacity temperature limit or the heat capacity level limit would be more appropriate.
In addition, it is not clear why the loss of all systems needed to achieve cold shutdown should be logically connected by "and" with the suppression pool parameters.
For, example, if the suppression pool parameters exceed the given setpoint but ADS was available would the heat removal capability be adequate?
~ I
Please provide justification for the parameters used in this EAL and address the concern of the loss of heat removal systems being logically connected with the suppression pool parameters by the word "and".
Loss of reactor vessel water level as indicated by:
a.
Loss of all decay heat removal cooling as determined by (site-specific) procedure b.
(Site-specific) indicators that the core is or will be uncovered.
The corresponding SSES EAL is "Reactor Pressure Vessel Water level below the Top of Active Fuel."
Contrary to the NUMARC EAL, the SSES did not include the conditions that all decay heat removal is lost or indication that the core will be uncovered.
Please provide justification for this deviation.
Loss of all onsite communications capability affecting the ability to perform routine operations.
See table 7.4.3 (Table 7.4.3 lists the following systems; UHF radio, VHF
- radio, ETN,
- CTN, and Plant PA)
Please explain how'the ETN and CTN are used for in-plant communication and how plant operation is maintained with the loss of the plant PA and radio systems.
In addition describe how radio communications are made in-plant, e.g.
EAL 7.4. I.b Loss of all offsite communications.
See "Table 7.4.3 (Table 7.4.3 contains the following systems;
- VHF, ETN,
- CTN, FTS-2000, Portable Cellular telephones)
Please describe how each of the above systems are used to communicate emergency information to offsite officials and why all of these systems need to be lost to meet the threshold of an Unusual Event.
EAL 7.4.3 Unplanned loss of most or all safety system annunciators which causes a significant loss of assessment capability, and, Significant plant transient in progress (Unplanned power change
>15%%d, ECCS actuation, reactor scram),
and Loss of SPDS and plant computer, and Loss'f most or all control room indications needed to monitor plant essential safety functions (power, reactor pressure, level, drywell pressure)
Please explain how the "loss of most or all control room indication needed to monitor essential safety functions" would be applied for this EAL.
For
- example, describe how an event where the only indication lost was the reactor vessel level would be classified?
EAL 7.5.2 Confirmed flooding within a plant vit'al structure which has affected plant systems required to establish or maintain cold shutdown (Control structure Diesel generator buildings, ESW pump house, reactor buildings)
Please explain how this EAL will be applied if, for example, one ECCS pump room was flooded, or one ESW bay were to be flooded.
EAL 8.1.2 Confirmed hostile intrusion or act in the plant Protected area as indicated by; one or more armed person(s) has breached the protected area barrier surreptitious altering of plant equipment or control mechanisms. essential to the safe operation or shutdown of the reactors Please explain what is meant by an "armed" person and why a hostile person must be armed to meet this EAL.
EAL 8.1.3 Confirmed hostile intrusion or act in the plant VITAL STRUCTURES as indicated by; One or more armed person(s) has breached a vital area of the plant (excluding the security control center),
or an explosive device has been found which, if detonated, would have a negative impact on the safe operation or shutdown of a reactor Please explain what is meant by an "armed" person and why a hostile person must be armed to meet this EAL.
In addition, explain how a determination is to be made as to whether an explosive device would have a negative impact on the safe operation.
For example, are control. room or security personnel to estimate the size of the explosion7 EAL 8.2.l.b Report or detection of an on-or near-site, release of toxic or flammable gases which may affect normal site operations (15 minutes after verification)
The corresponding NUMARC EAL does not include the condition "15 minutes after verification."
Please explain how the parameter'15 minutes after verification" is to be applied in classifying events using this EAL and why this parameter is necessary.
General Comments Re ardin the SSES Fission Product Barrier EALs Contrary to the NUMARC guidance, SSES chose not to include a fission product barrier matrix in its EAL scheme.
It is not necessary for the SSES EAL scheme to include a fission product barrier matrix as long as the SSES classification scheme will result in classification consistent with the NUMARC guidance.
Under the NUMARC EAL scheme, events involving the degradation of one or more of the fission product barriers (fuel clad,
- RCS, and Containment) are first assessed to determine which barriers are lost (based on indications of containment
- pressure, radiation levels, coolant activity etc.)
and are then classified based on the combination of barriers which are lost.
Under the SSES
- scheme, the classification process is simplified somewhat by not first determining'which barrier(s) has been lost (based upon indication of containment
- pressure, etc.) but rather classifying on the indication itself.
For instance, under the NUMARC scheme, water level less than top of active fuel is an indication of the loss of the fuel clad and RCS barrier.
The loss of the fuel clad and RCS barriers is classified as a Site Area Emergency.
Under the SSES
- scheme, water level being lower than top of active fuel is directly classified as a Site Area Emergency without going through the intermediate step of determining which barriers have been lost.
Even though classification may be simplified in some cases under the SSES
- scheme, the staff has identified two areas of concern with the SSES scheme.
The first concern is that under the SSES scheme there is the loss of recognition of what barrier failure the indication (e;g., drywell pressure) is related to.
This concern could be addressed by using ICs in the EAL matrix.
The second concern is that in a number of cases the SSES EAL scheme does not result in an equivalent classification as the NUMARC scheme.
In a letter dated October 2,
- 1995, SSES responded to NRC concerns regarding the equivalence between the NUHARC EAL scheme and the SSES scheme stating that:
"PP&L has reviewed all combinations of events that would indicate the loss or potential loss of a fission product barrier to assure that the classification scheme results in an event being classified consistent with that resulting from using the NUMARC methodology.
This review concluded that the proposed EALs are consistent with the NUHARC methodology...."
However, the NRC has identified a number of SSES EALs which are not consistent with the NUMARC guidance.
Examples of deficient EALs are provided in the Appendix to this RAI.
tI ft 4
f'
C v"n.he number "
concerns identified with the SSES fission product barrier classification methodology;-'it appears that the methodology may not be appropriate for classifying events based upon indications of the loss or potential loss of fission product barriers.
Please address the concerns addressed in these examples and provide the results of a detailed'evaluation which I) shows how the SSES EALs are equivalent to the NUHARC EALs, and 2) justifies any deviations.
Attachment:
Appendix Specific Concerns Identified with the SSES -Fission Product Barrier EALs
Appendix SPECIFIC CONCERNS IDENTIFIED WITH THE SSES FISSION PRODUCT BARRIER EALS NUMARC EALs Cate prized under the Loss of Containment Barrier.
NUNRC EAL 1 Rapid unexplained decrease following initial increase This NUMARC EAL corresponds to the loss of the containment barrier.
The loss of the containment barrier (by itself) is classified as an Unusual Event.
The classification escalates upon indications of a loss or potential loss of additional fission product barriers.
The corresponding SSES EAL is "Rapid, unexplained decrease in Drywell Pressure following initial pressure rise above 3.0 psig AND Indication of a leak into containment."
SSES did not include an Unusual Event EAL for this indication stating that this indication corresponds to the loss of RCS and containment and therefore is classified as a Site Area Emergency.
This is acceptable.
However, the SSES EAL does not escalate to a General Emergency based upon indication of fuel damage.
This is unacceptable.
In addition, the SSES does not provide a threshold for "indication of a leak into containment."
This may result in confusion when classifying the event.
This is unacceptable.
Please revise this EAL to be consistent with the NUMARC guidance or provide additional justification for this deviation.
NUMARC EAL 2a Failure of both valves in any one line to close AND downstream pathway to the environment exists The SSES EAL scheme did not include a fission product barrier EAL corresponding to this EAL.
The SSES justification for this is that "These conditions are covered under Tech Specs.
Failure to meet Tech Spec LCO will result in an Unusual Event."
This is an unacceptable deviation.
The NUMARC EAL does not correspond to the failure to meet technical specification LCO requirements but rather to the loss of the containment barrier.
In addition, a Site Area Emergency EAL (for the loss of the containment barrier in conjunction with the loss of the RCS or fuel clad barrier) and a General Emergency EAL (for the loss of the containment barrier in conjunction with the loss of the fuel clad and RCS barriers) needs to be added to the SSES scheme.
Please revise this EAL to be consistent with the NUMARC guidance or provide additional justification for this deviation.
ATTACHMENT
NUMARi EAL &b intentional Venting per EOPs This NUMARC EAL corresponds to the loss 'of the containment barrier.
The loss of the containment barrier (by itself) is classified as an Unusual Event.
The classification escalates upon indications of a loss or potential loss of additional fission product barriers.
The SSES EAL scheme included an EAL corresponding to this EAL classified at the Unusual Event level.
However the SSES did not include a Site Area Emergency EAL (for the loss of the containment barrier in conjunction with the loss of the RCS or fuel clad barrier) and a General Emergency EAL (for the loss of the containment barrier in conjunction with the loss of the fuel clad and RCS barriers).
The SSES EAL scheme should include these EALs.
The SSES technical basis states that "Escalation to the Alert classification would be based on the loss of either the fuel clad barrier or the Reactor Coolant System."
Under the NUMARC scheme the loss of the containment barrier (as indicated by intentional venting) in conjunction with the loss of the fuel clad barrier or the reactor coolant barrier would be a Site Area Emer enc not an Alert.
Furthermore, under the NUMARC scheme, a General Emergency should be declared if the drywell was intentionally vented when the loss of the fuel clad and RCS barriers existed.
Please justify this discrepancy between the NUMARC and SSES EAL schemes.
NUMARC EAL 2c Unisolable primary system leakage outside drywell as indicated by area temperature or area radiation alarm This NUHARC EAL corresponds to the loss of the containment barrier and the potential loss of the RCS barrier.
This condition (absent indication of any other barrier loss or potential loss) would be classified as a Site Area Emergency.
The classification escalates upon indications of a loss of the fuel clad barrier.
The corresponding SSES EAL (4. 1.3) is; "An Unisolable Primary System Leak is discharging into Secondary Containment AND Secondary Containment Temperature exceeds Maximum Safe Temperature Limit in any area of Table 4. 1. 1."
The SSES EAL deviates from the NUHARC guidance by logically connecting with the word "and," the condition of the unisolable primary system leak into secondary containment with the condition of secondary containment temperature above a given setpoint.
The condition of an unisolable primary system leak into secondary containment is, by itself, indicative of a Site Area Emergency condition.
The condition of secondary containment temperature above a given setpoint is used in the NUMARC guidance as a readily observable indication of an unisolable primary system leak.
Please justify including both conditions in the SSES Site Area Emergency EAL.
This comment also applies to SSES EALs 4. 1.4, 4.2.3, 4.2.4, 5.4.3 and 5.4.4.
0(
I NUMARC EALs Cate prized under the Potential Loss Containment Barrier NUHARC EAL la.
(Site-specific) psig and increasing The site-specific pressure for this EAL corresponds to the containment design pressure.
This NUMARC EAL corresponds to the potential loss of the containm nt barrier.
The potential loss of the containment, barrier (by itself) is classified as an Unusual Event.
The corresponding SSES EAL is "Drywell Pressure or Suppression Chamber Pressure exceed Containment Haximum Internal Pressure
> 53 psig."
SSES did not include an Unusual Event EAL for this indication of the loss of Containment because this EAL is also an indication of the loss of RCS (which
'is also the case under the NUMARC scheme).
Under the NUMARC scheme the loss of the containment and RCS barriers is classified as a Site Area Emergency.
Therefore, it is acceptable for the SSES EAL scheme to not include an Unusual Event EAL based upon drywell pressure.
However,, the SSES scheme did not include Site Area Emergency EAL for this indication.
- Rather, the SSES scheme classifies drywell pressure greatt;r than design pressure as a General Emergency.
This deviation has not been justified.
.A General Emergency classification would be justified if there was indication of the loss of the fuel clad barrier in conjunction with the containment pressure above its design limit.
Please revise this EAL to be consistent with the NUMARC guidance or provide additional justification for this deviation.
NUMARC EAL l.b Explosive Mixture Exists This NUMARC EAL corresponds to the loss of the containment barrier.
The loss of the containment barrier (by itself) is classified as an Unusual Event.
The classification escalates upon indications of a loss or potential loss of additional fission product barriers.
The corresponding SSES EAL is "Containment Hydrogen Concentration
>4X" and is classified at the Unusual Event level.
This plant condition is not combined with indications of the loss or potential loss of any other, fission product barriers to escalate the event to the Site Area Emergency level.
r Please justify this deviation.
NUMARC EALs Cate prized under the Loss of Fuel Clad Barrier NUMARC EAL 1 Coolant Activity GREATER THAN (site-specific) value This NUMARC EAL corresponds to the loss of the fuel clad barrier.
The loss of the fuel clad barrier (by itself) is classified as an Alert. The classification escalates upon indications of a loss or potential loss of additional fission product barriers.
The corresponding SSES EAL, "Reactor Coolant Activity Determined by Sample
(>
300 pCi/gm )" is also classified at the Alert level.
However, the event does not escalate to Site Area Emergency based on the following conditions:
Loss of RCS (as indicated by containment pressure greater than the alarm setpoint) or Loss of containment (e.g.
as indicated by failure of both isolation valves)
Furthermore, the event does not escalate to a General Emergency based on the indications of the loss of the RCS and containment barriers.
In addition, a related General Emergency level EAL (SSES EAL l. 1.4),
"Reactor Coolant Activity Determined by Sample
(> 2000 pCi/gm )
AND Primary Containment Integrity Cannot be Maintained," is deficient in that the EAL does not specify indications for the condition "Primary Containment Integrity Cannot be Maintained."
Please revise this EAL to be consistent with the NUMARC guidance or provide additional justification for this deviation.
NUMARC EAL 2 Reactor Vessel Level Less Than (site-specific) value This NUMARC EAL corresponds to the loss of the fuel clad barrier.
The loss of the fuel clad barrier (by itself) is classified as an Alert.
The classification escalates upon indications of a loss or potential loss of additional fission product barriers.
The corresponding SSES EAL, "Reactor Pressure Vessel Mater level Below the Top of Active Fuel (TAF)" is classified as a Site Area Emergency due to the condition of water level below TAF (top active fuel) being indicative of a loss of the fuel clad barrier and a loss of the RCS barrier.
This is acceptable.
However, this EAL is not combined with indications of the loss or potential loss of the Containment barrier for escalation to a General Emergency.
Please revise this EAL to be consistent with the NUMARC guidance or provide additional justification for this deviation.
NUMARC EAL 3 Drywell Radiation Monitor Reading, GREATER THAN (site-specific)
R/hr This NUMARC EAL corresponds to the loss of the fuel clad barrier.
The loss of the fuel clad barrier (by itself) is classified as an Alert. The classification escalates upon indications of a loss or potential loss of additional fission product barriers.
The corresponding SSES EAL, "Valid Containment High Radiation Monitor (> 60 R/hr)" is classified at the Alert level.
The classification appropriately escalates upon indication of a loss or potential loss of additional fission product barriers with the following exception.
The EAL does not escalate to a Site Area Emergency based upon an indication of a loss of RCS as i'ndicated by containment pressure greater than the alarm setpoint.
In addition, a related General Emergency level EAL (SSES EAL 1.2.3),
"Valid Containment High Radiation Monitor (> 60 R/hr)
AND Primary Containment Integrity Cannot be Maintained," is deficient in that the EAL does not specify indications for the condition "Primary Containment Integrity Cannot be Maintained."
This may result in delayed or erroneous classifications.
Please revise this EAL to be consistent with the NUHARC guidance or provide additional justification for this deviation.
NUMARC EALs Cate prized under the Loss of RCS Barrier NUMARC EAL 2 Drywell Pressure Greater THAN (site-specific). PSIG The NUMARC EAL is classified as Alert if there is no indication of a loss of the fuel clad or containment barriers.
The classification escalates upon indications of a loss or potential loss of additional fission product barriers.
The corresponding SSES EAL, "Drywell Pressure
> 3.0 psig" is also classified at the Alert level.
However, the event does not escalate to Site Area Emergency based on the following indications:
Loss or potential loss of primary containment as indicated by failure of both isolation valves, or intentional venting per
- EOPs, or explosive mixture exists.
Loss of. fuel clad barrier as indicated by elevated coolant activity or high drywell radiation monitor readings In addition, the event does not escalate to a General Emergency based on the loss of the RCS (as indicated by the high drywell pressure) in conjunction with the loss of fuel clad (by elevated coolant activity or high drywell radiation monitor readings) and the loss or potential loss of containment.
Please revise this EAL to be consistent with the NUMARC guidance or provide additional justification for this deviation.
NUMARC EAL Emergency Director Judgement The NUMARC EAL scheme includes EALs for the loss or potential loss of a fission product barrier based upon; "any condition in the judgement of the Emergency Director that indicate Loss or Potential Loss of the FUEL CLAD (RCS, CONTAINMENT) barrier."
The SSES EAL scheme does not include an equivalent EAL.
Please revise this EAL to be consistent with the NUMARC guidance or provide additional justification for this deviation.