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#REDIRECT [[B17237, Submits Response to RAI Dtd 980224,relating to Summary Rept on Verification of Seismic Adequacy of Mechanical & Electrical Equipment in Attachment 1.Util Commitments,Encl]]
| number = ML20248C679
| issue date = 05/21/1998
| title = Submits Response to RAI Dtd 980224,relating to Summary Rept on Verification of Seismic Adequacy of Mechanical & Electrical Equipment in Attachment 1.Util Commitments,Encl
| author name = Bowling M
| author affiliation = NORTHEAST NUCLEAR ENERGY CO.
| addressee name =
| addressee affiliation = NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
| docket = 05000336
| license number =
| contact person =
| document report number = B17237, TAC-M69459, NUDOCS 9806020223
| document type = CORRESPONDENCE-LETTERS, INCOMING CORRESPONDENCE
| page count = 12
}}
 
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                    ' Nuclear Energy                                              win,too, Noaca, rmr sww                          i Northeast Nudear Energy Company' P.O. Box 128 Waterford, CT 06385-0128 (860) 447-1791 Fax (860) 444-4277 -
                                                                                  & Northeas' tUtilities System MAY 2.1 1998 Docket No. 50-336 B17237 U.S. Nuclear Regulatory Commission
              - Attention: Document Control Desk Washington, DC 20555 l
Millstone Nuclear Power Station, Unit No. 2 Response to The Request For Additional Information Relating to The Summary Report On Verification of The Seismic Adequacy of Mechanical and Electrical Equipment, (Tac No. M69459)
This letter provides Northeast Nuclear Energy Company's (NNECO) response to the request for additional information' relating to the summary report on the verification of seismic adequacy of mechanical and electrical equipment'.
The NRC letter requests that NNECO submit a written response to six questions regarding operator actions specified.in the summary report. Attachment 1
                .provides NNECO's response to these six questions.
NNECO's commitments associated with this letter are provided in Attachment 2.
              '      D. J.' Mcdonald Jr., NRC letter to M. L. Bowling, " Request For Additional Information Relating to The Summary Report On The Verification of The Seismic Adequacy of i                    . Mechanical and Electrical Equipment-. Millstone Nuclear Power Station, Unit No. 2, Tac No. M69459)," dated February 24,1998.-
                    -(E.' A. DeBarba, Letter to Nuclear Regulatory Commission, ." Mil! stone Nucl
    ,i              (Staten, Unit No. 2. USl A-46 Walkdown Summary Report and Proposed Expansion
%                    ' of Licensing Basis for Verification of Equipment Seismic Adequacy," dated January
                    '22,1996.
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: .- if.S. Nuclear Regulatory Commission B17237/Page 2 Should you have any questions regarding this submittal, please contact Mr.
Ravi G. Joshi at (860) 440-2080.
Very truly yours, .
NOR THEAST NUCLEAR ENERGY COMPANY M. L. Bowling, Jr. V Recovery Officer - Technical Services Attachments cc:    W. D. Travers, Ph.D, Director, Special Projects Office H. J. Miller, Region I Administrator D. G. Mcdonald, Jr., NRC Senior Project Manager, Millstone Unit No. 2 D. P. Beaulieu, Senior Resident inspector, Millstone Unit No. 2 P. F. McKee, Deputy Director of Licensing - Special Projects Office W. D. Lanning, Deputy Director of Inspections - Special Project Office t
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Docket No. 50-336 B17237-1 l
l Attachment 1 Millstone Nuclear Power Station, Unit No. 2 Response to The Request For Additional Information Relating to The Summary Report On Verification'of The Seismic Adequacy of Mechanical and Electrical Equipment May 1998 1
  +
 
      . U.S. Nucirr R:guintory Commission B17237/ Attachment 1/Page 1 Millstone Nuclear Power Station, Unit No. 2 Response to The Request For Additional Information Relating to The Summary Report On Verification of The Seismic Adequacy of Mechanical and Electrical Equipment This attachment provides response to the request for additional information' relating to the summary report on verification of seismic adequacy of mechanical and electrical equipment *. The NRC request includes six questions (a) through (f).
Response to NRC Staff Question 'a.'
Question
: 1) Describe what reviews were performed to determine if any local operator actions required to safely shut down the reactor, such as implementing the Safe Shutdown Equipment List (SSEL), could be affected by the potentially adverse environmental conditions (such as loss of lighting, excessive heat or humidity, or in-plant barriers) resulting from the seismic event. 2) Describe how staffing was evaluated and 3) describe the reviews that were conducted to ensure operators had adequate time and resources to respond to such events.
Millstone Unit 2 Response This question is composed of three sub-questions, identified above as 1),2) and 3) and is considered to be fully associated with local operator actions outside the control room. Each is eddressed separately below.                                                      )
I 5
: 1) As described in Generic implementation Procedure , (GlP-2), Part II, Section 3.2.5,          l the only potential events which must be considered in the USl ~A-46 program are a            J '
design basis safe shutdown earthquake (SSE) and a loss of offsite power (LOOP).
Plant operating procedures used to shut down the reactor, which also address a LOOP, were reviewed and validated during the determination of the safe shutdown path and
* D. J. Mcdonald Jr., NRC letter to M. L. Bowling, " Request For Additional Information Relating to The Summary Report On The Verification of The Seismic Adequacy of Mechanical and Eled-ical Equipment- Millstone Nuclear Power Station, Unit No. 2, (Tac No. M69459)", dated February 24,1998.
d E. A. DeBarba, Letter to Nuclear Regulatory Commission, " Millstone Nuclear Power Station, Unit No. 2, USI A-46 Walkdown Summary Report and Proposed Expansion of Licensing Basis for Verification of Equipment Seismic Adequacy.", dated January 22,1996.
5
            " Generic implementation Procedure (GIP) for Seismic Verification of Nuclear Fiant Equipment," Revision 2, corrected 2/14/92, Seismic Qualification Utility Group, February  i J
1992.
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            . U.S.'Nucl=r R:gulatory Commission B17237/ Attachment 1/Page 2 equipment list for the USl A-46 program'.              This includes potentially adverse envirorvoental conditions such as loss of lighting and excessive heat and humidity.
Note that the USI A-46 accident scenario (SSE+ LOOP) explicitly excludes loss of coolant accidents (LOCA) and high energy line breaks (HELB). Therefore, the heat and humidity conditions in the plant are postulated to be equivalent to those in a LOOP scenario.
As indicated in our " Preferred Safe Shutdown Paths for Millstone Unit 2" report', no other extraordinary events are postulated (i.e., LOCA, fire, HELB, etc.) simultaneous with the seismic event. However, in response to the question:
* Appendix R lighting was seismically installed to prevent any seismic II over I interaction, in plant design change records 2-062-86 and 2-073-86, and would provide the necessary supplementary lighting, in addition to the heavy duty flashlights which are always carried by operators, to the areas where local operator actions are required.
              . Since no LOCA or HELB is postulated simultaneously with the seismic event, no excessive heat or humidity is anticipated in any of the areas in the routes to where local operator actions will be required.
              . Since the structures housing the equipment on the Safe Shutdown Equipment List (SSEL) have all been seismically analyzed for the SSE (Millstone Unit No. 2 FSAR, Chapter 5), and seismic II over I reviews have been conducted in the local vicinity of the SSEL equipment, no major insurmountable in-plant barriers would be expected in the areas or in the routes to where local operator actions will be required. The potential for failure of plant structures and equipment is not considered credible at eastern US earthquake levels. Earthquake experience has shown that typical industrial structures are able to withstand earthquakes larger than the SSEs for eastern U.S. nuclear plants without collapse or failure.
Furthermore, the potential for local failure of architectural features and the potential for adverse seismic spatial interactions in the vicinity of the safe shutdown equipment, where local operator actions may be required, was explicitly evaluated as required in GIP-2, Part II, Section 4.5 and Appendix D. For example, this review included a check that the masonry walls near safe shutdown equipment are seismically adequate.
: 2) The systems and equipment selected for seismic review in the USl A-46 program are those for which Normal, Abnormal, and Emergency Operating Procedures are available to bring the plant from a normal operating mode to a hot shutdown condition.
As required by GlP-2, Part II, Sections 3.2.8 and 3.7, the SSEL was reviewed by the plant Operations Department to confirm that it is compatible with these plant procedures. As indicated in our " Preferred Safe Shutdown Paths for Millstone Urit 2" Generic Letter 87-02. " Verification of Seismic Adequacy of Mechanical and Electrical Equipment in Operating Reactors, Unresolved Safety issue (USI) A-46," U.S. Nuclear Regulatory Commission, February 19,1987.
 
                                            , U.S.'Nuclecr Regulatory Commission B17237/ Attachment 1/Page 3 report", tne safe shutdown paths selected for the GL 87-02/USl A-46 evaluations are similar to those used to shutdown the plant in the event of a fire. During the development of the shutdown path for this program, existing procedures were reviewed and found adequate to address the shutdown requirements for this program. Since no major procedural changes were anticipated as a result of. the USl A-46 program, staffing requirements associated with those procedures were anticipated to be adequate to address the requirements for this program and it was not necessary to re-validate the procedures for the USI A-46 program.
The only additional operator actions, which were found to be required as a result of the A-46 program, are those described in our response to question 'd' associated with resetting nine (9) relays. As described in our response to question 'd', this operator
                                            - action is anticipated to be performed from the control room and will not require any additional staffing or resources.
: 3) As indicated in item 2 above, existing procedures were relied upon in developing the shutdown path for this program. Since the shutdown path is similar to that for Appendix R, manpower resources and response time were anticipated to be enveloped by those for Appendix R.
Response to NRC Staff Question 'b.'
Question As part of the review, were any control room structures, which could impact the operator's ability to respond to the seismic event, identified? Such items might include but are not limited to ceiling tiles, non-bolted cabinets, and non-restrained pieces of equipment (i.e., computer keyboards, monitors, stands, printers, etc.). Describe how each of these potential sources of interactions has been evaluated and describe the schedule for implementation of the final resolutions.
Millstone Unit 2 Response An A-46 walk'down of the control room was performed as part of the GL 87-02 project.
Control Room structures and components which could impact the operator's ability to respond to a safe shutdown earthquake were identified and reviewed during the walk down. Items reviewed included, but were not limited to, equipment cabinets, filing cabinets, printers, copiers, ceiling tiles, computer equipment, desks, tables, and other miscellaneous items in the' control room. The method used for evaluating these
                                            , potential sources.of seismic spatial interaction is described in GIP-2, Part II, Section
                                            ' 4.5 and Appendix D. Several corrective actions were identified associated with anchoring some equipment cabinets,. filing cabinets, and lockers. All - of these
                                            - corrective actions have been fully implemented.
 
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                              . U.S.'Nucirr Regulatory Commission
                              - B17237/ Attachment 1/Page 4 Response to NRC Staff Question 'c.'
                              - Question Demribe what reviews were performed to determine if any local operator actions were required to reposition " bad actor relays". For any such activities describe how adverse environmental conditions (such as loss of lighting, excessive heat or humidity, or in-plant barriers) resulting from the seismic event were analyzed and dispositioned.
Describe how staffing was evaluated and describe the reviews which were conducted to ensure operators had adequate time and resources to respond to such events.
Millstone Unit 2 Response The term " bad actor" relays is an expression which refers to the list of relays in Appendix E of EPRI Report NP-7148. These relays have Ic seismic ruggedness or demonstrated sensitivity to high frequency vibration. The term used in EPRI NP-7148 characterizes these relays as " low ruggedness" relays.
The A-46 walkdowns identified six (6) essential relays of the same make and model that could potentially be " low ruggedness" relays. However, a subsequent evaluation confirmed these relays to possess characteristics which do not classify them as " low ruggedness" type. Furthermore, since the respective relay GERS do not envelop the seismic demand for these relays at present, a modification is in progress to move the relays to a location of lower seismic demand which is enveloped by the relay capacities. This change will be completed before entering MODE 4.
Therefore, since after implementation of the modification, we will not have any " low ruggedness" relays which will require resetting after a seismic event, no local operator actions will be required.
Resaonse to NRC Staff Question 'd.'
Question Describe which of the operator actions associated with resetting SSEL equipment affected by postulated relay chatter are considered to be routine and consistent with the skill of the craft. If not considered skill of the craft, what training and operational aids were developed to ensure the operators will perform the actions required to reset affected equipment.
Millstone Unit 2 Response Resetting of relays which may have actuated as a result of a safe shutdown earthquake is consistent with the skill of the craft of our operators. Resetting these relays is an r
 
,s    l  . U.S.Nucimr Regulatory Commission                                                              a B17237/ Attachment 1/Page 5                                                                  l activity which is included within the scope of expected operator actions contained in our Normal, Abnormal, and Emergency Operating Procedures.
Nine (9) relays were identified for which resetting 4.16 KV breakers affected by postulated relay chatter may be required. If required, these relays will be reset from the '
control room by means of local handswitches on the control boards which will reset the affected breakers. Subsequently as time allows, resetting of the local alarm flags will be implemented by an operator at each of the affected switchgear using routine action which is considered skill of the craft knowledge.
Response to NRC Staff Question 'e.'
Question
            ' Assume the alarms associated with " bad actor relays" are expected to annunciate during the seismic event. Do the operators have to respond to those annunciators and review the annunciator response procedures associated with them for potential
          - actions? How would those additional actions impact the operators' ability to implement the Normal, Abnormal, and Emergency Operating Procedures required to place the reactor in a safe shutdown?
Mi.llstone Unit 2 Response As discussed in our response to NRC question 'c' above, the term " bad actor" relays is an expression which refers to the list of relays in Appendix E of EPRI Report NP-7148.
These relays are called " low ruggedness" relays.
As described in EPRI Report NP-7148, Section 3.5.3, following an earthquake which causes the turbine to trip and the reactor to scram, numerous alarms are expected to annunciate. In addition to these alarms, there may_ be several earthquake-induced, spurious alarms resulting from such events as water sloshing in tanks, oil sloshing in transformers, actuation of vibration protective instrumentation on rotating equipment, and contact chatter of relays. These alarms will alert the operator that the plant has
          . tripped. Plant procedures and operator training require that operators respond to the
            . turbine trip and reactor scram by confirming the scram and trip and checking important levels,- temperatures, pressures, flows, and electrical switching resulting from
: associated power transfers. These confirmatory checks will take longer than the
          . postulated duration of the earthquake motion and thus the operator will not be
          . responding to the alarms resulting from the earthquake vibration. The operators will be responding to the plant trip after the earthquake has terminated and the causes of the earthquake-induced alarms has stopped.~
__=__:__-__-___-          _ _ = _ _ _ _ _ _ -
 
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    . U.S/Nucl=r Regul tory Commission B17237/ Attachment 1/Page 6 The NRC staff and Seismic Qualification Utility Group (SQUG) representatives discussed this topic in detail, including discussions held at a meeting on August 3, 1988, where this was a primary topic of discussion. The results of that eva!uation and review are summarized in EPRI NP-7148, Section 3.5.3 where the following conclusion is reached.
              "Accordingly, there appear to be no reasonable bases or evidence which would suggest that spurious alarms resulting from an earthquake may lead to abnormal operator responses. Therefore, special operating procedures or relay evaluation actions to address potential spurious alarms are not considered warranted and relays affecting alarms need not be seismically adequate."
The NRC staff accepted the relay functionality review procedure summarized in GIP-2 and described in detail in EPRI NP-7148 (including the above conclusion) in Suppismental Safety Evaluation Report No. 2 on GIP-2. Therefore, we do not consider it necessary to perform additional reviews of the effect spurious alarms caused by " low ruggedness" relays or other causes as a result of a seismic event.
Response to NRC Staff Question 'f.'
Question To the extent that Normal, Abnormal, and Emergency Operating Procedures were modified to provide plant staff with additional guidance in mitigating the Unresolved Safety issue A-46 seismic event, describe what training was required and provided to the licensed operators, non-licensed operators, and other plant staff required to respond to such events.
Millstone Unit 2 Response Section l1.3.2.8 of GlP-2 states that existing Normal and Emergency Operating Procedures (EOPs) are expected to be sufficient to lead operators to use appropriate operational equipment and systems following the SSE, and operators are expected to be trained in their use. As stated in the SQUG (Neil Smith) letter to the NRC (James Partlow) dated August 21,1992, SQUG's understanding of the NRC staff's position on operator training (as described in SSER No. 2 on GIP-2, Section ll.3, Evaluation and Conclusion, item 2) is that appropriate training on plant procedures is required only when it becomes necessary to change these plant procedures to achieve compatibility with the SSEL. Training need be provided only to the extent necessary to familiarize operators with changes to these procedures as a result of the A-46 program.
The only change in plant procedures, identified to date, that has been necessitated by the A-46 program pertain to the potential of resetting of 4.10 KV breakers due to relay chatter. The associated operator action needed is a result of the potential chatter of
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                    .a      &
                              . U.S. Nuclear R:gulatory Commission B17237/ Attachment 1/Page 7 nine (9) relays discussed in response to NRC question 'd' and will be incorporated into AOP 2562 " Earthquake." This potential relay chatter may cause a trip of the associated breaker which will provide indication in the control room. Revision to the procedure wili highlight the need to reset the relays, and thus the breakers, from the control room should they trip due to the seismic event. This procedural change is considered a minor change and will simply require familiarization of the change by operators and other appropriate plant personnel. The procedure change and operator familiarization .
will be completed before entering MODE 4.
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Docket No. 50-336
                                            ^
B17237 Attachment 2 Millstone Nuclear Power Station, Unit No. 2 Commitments Associated With Response to The Request For Additional Information Relating to The Summary Report On Verification of The Seismic Adequacy of Mechanical and Electrical Equipment May 1998.
U.N.-- - _ _ . _ _ _ .      . _ - - . _ _ .        -    _ - . _                                                          .
 
    , c.  ,,
U.S. Nucl=r Regulatory Commission D17237/ Attachment 2/Page 1 List of Regulatory Commitments                        !
The following table identifies those actions committed to by Northeast Nuclear Energy  a Company (NNECO)in this document.
COMMITMENT DATE OR REGULATORY COMMITMENT                              OUTAGE B17237 91    NNECO will        move six relays Before entering MODE 4.
(differential relays RA 069, RA 070, RA 071 & RA 081, RA 062, RA 083 presently located in DG 'A' Feeder Breaker Cubicle A312 and DG 'B' Feeder breaker Cubicle A401) to a location of lower seismic demand which is enveloped by the relay capacity.
B17237-02    NNECO will modify procedure AOP Before entering MODE 4.
2502 to incorporate additional operator actions needed to mitigate potential relay chatter of nine (9) relays which may affect resetting the 4.16 KV breakers and complete operator familiarization.
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