ML19340D167
| ML19340D167 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 12/19/1980 |
| From: | Mills L TENNESSEE VALLEY AUTHORITY |
| To: | Schwencer A Office of Nuclear Reactor Regulation |
| References | |
| RTR-NUREG-0737, RTR-NUREG-737 NUDOCS 8012290238 | |
| Download: ML19340D167 (28) | |
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TENNESSEE VALLEY AU i nORITY l
CH ATT ANOOGA, TENNESSEE 37401 400 Chestnut Street Tower II December 19, 1980 Director of Nuclear Reactor Regulation Attention:
Mr. A. Schwencer, Chier Licensing Branch No. 2 Division of Licensing U.S. Nuclear Regulatory Cosmaission t;ashington, DC 20555
Dear Mr. Schwencer:
In the Matter of
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Docket No. 50-327 Tennessee Valley Authority
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D. G. Eisenhut's letter dated October 31, 1980, which transmitted NUREG-0737, Cla, 'fication of TMI Action Plan Requirements, requires licensees to fbtish, pursuant to 10 CFR 50.54(f), confirmation that the requirements of NUREG-0737 will be met. Enclosed is a discussion of each item in NUREG-0737 which TVA considers te remain open on Sequoyah Nuclear Plant unit 1.
The items excluded from the enclosure have been resolved by TVA as documented in earlier correspondence. The Sequoyah Nuclear Plant report entitled "TVA's Response to NUREG-0578 Short Term Lessons Learned Requirements" will be revised to reflect the enclosed information.
Proposed license amendments are forthcoming that address the items listed in the enclosure cm which TVA is requesting relief with respect to instal-lation schedule.
Very truly yours, TENNESSEE VALLEY AUTHORITY
.Y L. M. Mills, er Nuclera Regulation and Safety Sworn,to d subscribed before me this / / f day of U S 8 -
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- An Equat Opportunity Employer
I.A.I.3 - Shift Manning TVA Response - TVA r.eets the requirements for shift manning for one unit operation at Sequoyah Nuclear Plant.
Sequoyah unit 1 Technical.Specifi-cation 6.2.2, " Unit Staff," lists the minimum shift crew for single unit operation'. Edn unit 7 is licensed, TVA wilI imend the unit 1 technical specifications to include minimum shift crew requirements for two unit operation with a single control room.
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I.B.l.2 - Independent Safety Engineering Group TVA Response - No change in the original Sequoyah licensing submittal on the ISEG is seen at this time.
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I.C.1 - Guidance for the Evaluation and Development of Procedures for Transients and Accidents TVA Response - The Westinghouse owners' group will submit by January 1, 1981, a detailed description of the program to comply with the requirements for this item. The program will identify owners' group previous sub-mittals to the NRC, which we believe will comprise the bulk of the response.
Additional effort required to obtain full compliance with this item (with proposed schedules for completion) will also be identified as discussed in the meeting with the NRC on November 12, 1980.
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I.C A - Verify Co rrec t Perfornance of Operating Activities TVA Respnysi - Curren plant administ rat Ive procedures require-(.)
All eseential safets t-yst ems and cemponent alignren t be verified prior to unit startup.
(b)
Changes la the alignnent of any safety system component he recorded on a system status sheet.
(c) Shift personnel being relicved cenn.unicate information on any abnormal plant conditian includina temporary conditions.
(d) System operability be denonstrated before a system is returned to service, and (e) Approval by the shift supervisor or his representative prior to the performance of any activity on safety-related plant ecuipment, or any activity that ma:. affect cafety-related plant equipment.
The shift suparvisor or his representative is notified when an activity authorized to be per formed on safety-related plant equipment is c mpleted or a chance occurs in the scope of the activity.
Plant operating instructious require con.plction of a startup checklist prior to unit startup.
fhir, checklist is used to verify cerrect alignment of all safety systems.
In addition, allenment of critical systems is reviewel each shift.
Anvtine a critical component is changed from its normal pnsition or conditi.in, a system status sheet is conpleted and placed in a system status folder.
Panel checklists are revietsed each shift t' verif y proper panel alinnment exists for all 4a fety nystems.
Seceay h is continuing their revleu of plant instructions to incorporate a exd verification of system alignment where needed.
It is TVA's opinian that this verification function can be perfor-ed adequately by an astiltant uait cperatar (AUO) and that the use of licensed unit operaters is not necessary.
The AUO has sufficient training and familiarity with olant systems to ensura correct system alignment, and this policy l
'n 11 11'on the licensed operator to remain in the control roon.
T'.T w i l l complet e the review of plant instructions and make any necessary chaanes by February 15, 1981.
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I.D.1 - Control Room Design Reviews TVA Response - TVA has conducted a preliminary design review of the Sequoyah control room. TVA also participated in a control room review with the NRC and its consultant, Essex Corporation.
Several immediate modifi-cations were made to the control room to improve communication capabilities, lighting, and noise levels. Changes were made to the control panels to pro-tect controls from inadvertent activation, highlighting was added to provide easy recognition of system controls and indicators, and alarm panel lighting contrast was improved. The details of the control room modifications have been transmitted to the NRC.
TVA is required to complete a long-term control room design review prior to restart afte'r the first refueling outage by license DPR-77 condition 2.C.22.C.
TVA will use NRC guidelines (NUREG-0700), when issued, in the long-term control room design review.
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I.D.2 - Plant Safety Parameter Display Console TVA Response - TVA will supply the NRC with the required information when additional clarifi:ation is provided (NURTG-0696).
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- !;c.ictor Coolant '/4t(m Vents TVA 1:a,ponFe 1.
Jent Desi;;n - The deci.;n it: formation on the Sequoyah vessel head vent
. tem will be submit ted on or before the scheduled July 1,1981, date.
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V. n t Instillation - TVA preposes to install the head vent system at the first refueline, outage instead of the scheduled date of July 1, l 'G 2.
Current projections have the first refueling out; ige occurring late as August 1992.
The date.lepends on the plant capacity u:
f.u: tor during the first cycle and can nove forward or backward as t he cycle develops.
The reascns and justifications fcr rescheduling t he conplet ion d.i t e for t his nod i fica t ion have been t ranamitted to
' '<C i n TVA 's response to NUREG-06% f r Sequoyah.
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pra edures - The head vent tuidelines being developed by the Westinghouse owners' group will be incorporatett into the Scquevah Ercrgency Operating Instructions.
This tuideline wil L be forwarded for your review by the owners' grcup on or before July 1, 1981.
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II.B.2 - Plant Shielding TVA Response - TVA has completed the design evaluations and nodifications required by this item and has submitted the required information.
It is our opinion that we have satisfied all portions of this requirement.
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II.B.3 - Post-Accident Sampling TVA Response - TVA expects to have available for review the final design details of the post-accident sampling facility for Sequoyah by January 1, 1981. Any deviations from the NRC position will be presented with our submittal.
The implementation date of January 1, 1982, for all modifications cannot be assured. TVA proposes to complete all modifications by first refueling outage. Current projections have the first refueling outage occurring as late as August 1982. The date depends on the plant capacity factor during the first cycle and can move forward or backward as the cycle develops. The reasons and justifications for rescheduling the completion date for this modification have been transmitted to NRC in TVA's response to NUREC-0694 for Sequoyah. The interim post-accident sampling system is installed.
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II.B.4 Training for Mitigating Core Damage TVA Response TVA has completed initial development of the training program for the shift technical advisors and operations personnel from the operations supervisor to the licensed operators to comply with Enclosure 3 of H. R.
Denton's durch 28, 1980, letter.
An abbreviated program of the operator training will be presented to managers and technicians in the llealth Physics, Plant Chemistry, and Instrumentation and Controls Sections commensurate with their responsibilities in the event of a core damaging accident.
Portions of this training are currently being implemented and full implementation is expected by April 1,1981.
Training for STA's will be performed during the requalification training program. We expect completion of the initial training program by January 1, 1982.
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II.D.1 - Relief and Safety Valve Test Requirements TVA Response - TVA vill reference the EPRI PWR Relief and Safety Valve Test Program as our response to this requirement.
Submittal dates will be updated by EPRI as the test program progresses.
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II.E.1.2 - Auxiliary Feedwater System Initiation and Flow TVA Response - TVA has submitted to the NRC information documenting the existing auxiliary feedwater system at Sequoyah.
It is our opinion that the existing system complies with the requirements set out in NUREC-0737.
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II.E.4.2 - Containmant Isolation Dependability TVA Response - TVA has met or will meet the scheduled dates for all items of this requirement. Discussion with the NRC on part 6 of this requirement will continue until a satisfactory resolution has been reached. Attached is our submittal for the containment pressure setpoint study.
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ATTACHMENT Containment Pressure Setpoint The Sequoyah containment pressure high setpoint is required to be less than or equal to 1.54 psig by Technical Specification 3.3.2.1, " Engineering Safety Feature Actuation System Instrumentation." It is more than 1 psig above the highest primary containment internal pressure allowed by Technical Specification 3.6.1.4, " Containment Internal Pressure," however, TVA believes that the present containment pressure high setpoint is adequate. The reasons are stated below.
The containment pressure high channel actuates safety injection, turbine trip, and feedwater isolation.
Phase "A" containment isolation is actuated fron the safety injection logic. Reducing the containment pressure high setpoint increases the potential not only for inadvertent containment isolation but also inadvertent safety injection and feedwater isolation.
Adequate protection is already provided to prevent the release of radio-active materials following an accident. Phase "A" isolation, which includes containment ventilation isolation, is initiated by diverse signals, including all safety injection actuation cha mels including low pressurizer pressure, high gaseous or particulate activity in containment, and high activity in the purge air exhaust.
The containment pressure high and high-high setpoints and low pressurizer pressure setpoints are reached almost immediately in large loss of coolant accidents (LOCA).
Lowering the containment pressure high setpoint will not provide any additional safety margin to the accident analyses because of the speed at which the containment pressure rises for large LOCA's.
Two cases for small LOCA's are considered:
those for which the charging system can maintain reactor coolant system inventory and those that cannot.
In the first case, core uncovery will not occur and the radioactivity released is limited to the material contained in the coolant.
Containment vent isolation will occur.
The setpoint for the ventilation isolation signals are set to prevent releases exceeding 10 CFR Part 20 limits (normal release limits).
Lowering the containment pressure high setpoint will not provide any significant additional safety margin.
In the second case, safety injection will always occur much sooner than core uncovery.
Since phase "A" isolation occurs on safety injection, radioactivity releases prior to isolation are limited to material contained in the coolant.
Containment vent isolation will occur.
Lowering the containment pressure high setpoint will not provide any significant additional safety margina.
TVA believes that the present containment pressure high setpoint of 1.54 psig is adequate.
Reduction of this setpoint would provide no significant additional safety margin.
Instead, it would increase the potential for inadvertent containment isolation and safety injection.
II.F.1 - Accident Monitoring TVA Response - TVA has completed a preliminary evaluation of this require-ment and should meet the submittal dates presently scheduled except for item 2.
Further investigation into item 2 is proceeding to determine our ability to procure the equipment necessary to perform the intended function.
This problem will be outlined further in the January 1, 1981, submittal.
As noted in TVA's response to NUREG-0694 for Sequoyah, TVA is having difficulty in procuring equipment that meets the requirements for accident monitoring instruments.
In that response TVA committed to install the qualified instruments during the first refueling outage or the first outage of suf ficient duratica af ter the equipment is available.
This is still TVA's position on installation schedules, i
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II.F.2.3 - Instrumentation for Detection of I.C.C.
TVA Response - TVA will meet the January 1, 1981, date for the reactor vessel level design submittal. We propose, however, to delay the imple-mentation schedule until the first refueling outage to prevent an unnecessary shutdown of the unit during the first fuel cycle.
Since the procedures being developed by the Westinghouse owners' group utilizing the vessel level instrumentation are not required to be impicmented until the first refueling outage af ter January 1982, we feel that delaying completion of the instrumentation until the same time can have no effect on the safe operation of the plant.
The reasons and justifications for rescheduling the completion date for this modification have been transmitted to KRC in TVA's response to NUREG-0694 for Sequoyah.
The Westinghouse vessel level design is still in the development and test stage and TVA will continue reviewing the system for acceptability prior to proceeding with the installation.
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II.K.2.13 - Thermal Mechanical Report TVA Response - TVA has satisfied the requirements of this item for Sequoyah unit 1 as outlined in Sequoyah Safety Evaluation Report, Supplement 1, 15.3.3.
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II.K.2.17 - Potential for Voiding in the RCS i
TVA Response _ - The Westinghouse owners' group is addressing the potential for void formation in the reactor coolant system (RCS) during natur.:1 circulation conditions as described in Westinghouse letter NS-TMA-2298 (T. M. Anderson, Westinghouse, to P. S. Check, NRC). We believe the results of this effort will fully address the NRC requirement for analysis to determine the potential for voiding in the RCS during anticipated transients. A report describing the results of this effort will be providad to the NRC before January 1, 1982.
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II.K.3.1 and II.K.3.2 - Auto PORV Isolation and Failure Report TVA Response - The Westinghouse owners' group is in the process of developing a report (including historical valve failure rate data and documentation of actions taken since the TMI-2 event to decrease the probability of a stuck-open PORV) to address the NRC concerns on this item. However, due to the time consuming process of data gathering, breakdown, and evaluation, this report is scheduled for submittal to the NRC on March 1, 1981.
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I II.K.2.19 - Sequential Auxiliary Fee / water Flow Analysis TVA Response - The Westinghouse transient analysis code, LOFTRAN, and the present small break evaluations analysis code. VFLASH, have both undergone benchmarking against plant information or experi:nental test facilities. These codes under appropriate conditions have also been compared to each other. The Westinghouse owners' group will provide by January 1,1982, a report addressing the benchmarking of these codes.
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II.K.3.5 - Auto Reactor Coolant Pump Trip TVA Response - The Westinghouse proposed design modification for the automatic RCP trip has already been submitted to the NRC for review.
If it is required, TVA would install the modification prior to startup after the first refueling outage.
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II.K.3.17 - ECC System Outages Summary - Sequoyah unit 1 has approximately four months of operating experience and cannot add any meaningful information to the data base the NRC is seeking, but TVA will submit their plan for ECCS outage data collection by March 1, 1981.
TVA Response - Sequoyah unit 1 completed fuel loading March 1, 1980.
Since that time, approximately four months of operating experience have been gained.
No systematic plan of tracking cumulative outage times for ECC equipment was required at the time Sequoyah unit 1 was licensed. There fore, information on outages due to testing and maintenance is not readily available nor would it add any meaningful information to the data base the NRC is seeking with so little operating experience. However, TVA will implement a plan for gathering cumulative outage times for ECC equipment and transmit it to the NRC by March 1, 1981.
The plan for gathering cumulative outage times will include (1) outage dates and duration of outage, (2) cause of the outage, (3) ECC systems or components involved in the outage, and (4) corrective action taken.
In addition, proposed changes to improve the availability of ECC equipment will be made, if needed.
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1 II.K.3.25 - Effe i. cf Loss of Alternating Current Power on Pump Seals TVA Response - Sequoyah presently supplies emergency power to the com-ponent cooling water pumps through automatic sequencing onto the diesel generators after a loss of offsite power.
In light of this, regardless of the result of the pump seal analysis, it is our opinion that Sequoyah is presently in compliance with this requirement.
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II.K.3.30 and II.K.3.31 - Compliance with 10 CFR Part 50 TVA Response - The Westinghouse owners' group has responded to this require-ment in letter WOG 80-145.
The present approach has been to justify the acceptability of the existing small break LOCA models. The owners' group will submit additional information for model justification by January 1, 1982. Based on the January 1,1982, information, the need for plant specific analysis will be determined and would be expected to be completed in the required time frame.
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III.A.l.2 - Upgrade Emergency Support Facilities TVA Response - TVA will supply the NRC with the required information when additional clarification is provided (NUREG-0696).
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III.A.2 - Emergency Preparedness TVA Response - The radiological emergency plan (REP) and implementing procedures have been submitted to the NRC.
The REP is scheduled for revision and reformatting by January 2, 1981.
TVA will comply with the schedule date of March 1, 1981, for implementation of milestone 3.
Details of the implementation of milestone 3 will be provided at that time.
TVA will provide comments on the schedules and scope of milestones 4 through 8 following issuance and our review of the revised NUREG-0654.
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III.D.3.4 - Control Room Habitability TVA Response - TVA has evaluated poten* 11 hazards affecting the Sequoyah control room as reported in the Sequo;an Final Safety Analysis Report, section 2.2, 6.4, and 15.5.
As stated in TVA's letter dated July 24, 1980, TVA will provide a detailed review of the Sequoyah control room design by January 1, 1981, using the applicable Regulatory Guides and Standard Review Plan sections as guidance.
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