ML19350D049
| ML19350D049 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 03/31/1981 |
| From: | Trimble D ARKANSAS POWER & LIGHT CO. |
| To: | Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| References | |
| 1R-0481-02, 1R-481-2, 2R-0481-01, NUDOCS 8104130194 | |
| Download: ML19350D049 (9) | |
Text
e ARKANSAS POWER & LIGHT COMPANY POST OFFICE BOX 551 UTTLE ROCK, ARKANSAS.72203 (501)371-4000 March 31, 1981 p
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Mr. K. V. Seyfrit, Director
' DN S1 Office of Inspection & Enforcement U. S. Nuclear Regulatory Commission D ---
S Region IV 611 Ryan Plaza Drive, Suite 1000 Arlington, Texas 76011
Subject:
Arkansas Nuclear One-Units 1 & 2 Docket Nos. 50-313 and 50-368 License Nos. OPR-51 and NPF-6 10CFR50.59 Design Changes (File: 0520.2,2-0520.2)
Gentlemen:
In accordance with 10CFR50.59, attached is a report containing a brief description of our safety evaluation for design changes made to Arkansas Nuclear One-Units 1 and 2 ( ANO-1 and 2).
This report contains only those design changes which required a safety evaluation and were completed in 1980.
Very truly yours,
/
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/oDavid C. Trimble
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Manager, Licensing DCT:DET:tw cc: Mr. Victor Stello, Jr., Director Office of Inspection & Enforcement U. S. Nuclear Regulatory Commission Washington, D. C.
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ARKANSAS NUCLEAR ONE - UNITS 1 AND 2 DOCKET NOS. 50-313 AND 50-368 License Nos. DPR-51 and NPF-6 10 CFR 50.59 Design Changes in 1980 (File:
0520.2, 2-0520.2)
Design Change Number DESCRIPTIVE
SUMMARY
597 The o rpose of this change was to provide better temperature control of (ANO-1) tLe ICW coolers during the winter months by running an 8" bypass line from each inlet loop to the discharge header and supplying a 8" globe valve on each of the bypass lines.
As this change would reduce the possibility of failure of the system to perform its required function, the margin of safety for the health and safety of the public is not decreased.
This change creates no new accident possibilities, nor increases the probability of any accidents previously analyzed in the safety analysis.
79-1018 This change installed a double fire door in the Unit 1 Emergency Diesel.
'(ANO-1)
Generator Room on elevation 369'-0" and constructed a concrete unit masonry firewall above the door.
This change did not create the possibility of an unanalyzed accident, nor increase the probability or consequences of a previously analyzed accident.
The margin of safety as related to the health & safety of the public was not reduced.
l 79 D-1022 This change provided independent sources to each emergency feedwater (ANO-1) pump by dividing the single suction line into two lines.
Each line supplies service water to one emergency feedwater pump.
The purpose of separating the lines in this way was to provide independent and redundant service water supply to both or one of the emergency feedwater pumps. All control valves presently in the system will be maintained to provide a means of separating service water and condensate
'until such time as service water is required.
This change did not create the possibility of an unanalyzed accident, nor increase the probability or consequences of a previously analyzed accident.
The margin of safety as related to the health and safety of the public was not reduced.
79-1049A NUREG 0578 required initiation of emergency feedwater utilizing single (ANO-1) failure design criteria and control grade logic.
Accordingly, this required removal of the EFW initiation from ICS and adding it to the NNI-X and NNI-Y subsystems.
Since the possibility of an accident or malfunction of a different. type than any previously evaluated in the safety analysis report may have been created, NRC required that their review of this design change be completed prior to implementation.
(SEE LESSONS LEARNED TASK FORCE / BULLETINS AND ORDERS TASK FORCE)
Design Change Number
' Cont'd DESCRIPTIVE
SUMMARY
CONT'D 79-1059 This change modified the Engineered _ Safeguards System so that seventeen-(ANO-1). -(17) containment isolation valves would close diverse signals. The purpose of the design improvement was to allow for a backup initiating signal of-falling RCS pressure. Since a Technical Specification Change was involved, NRC approval was obtained prior to implementation.
79-1069 This change provided redundant seismic flow indication for the emergency (ANO-1)- -feedwater system.
Also, the electrical system was upgraded from control grade power to vital power.
The purpose of this change was to provide the operator with additional information during an abnormal event.
Refer to NUREG-0578.
This change did not create the possibility of any unanalyzed accident,~ nor increase the probability or consequences of any previously analyzed accident.
The margin of safety as related to the health & safety of the public was not reduced.
79-1075)
Per NUREG-0578 Requirements, this change provided for qualified, (ANO-1) redundant-ir ;trumentation to ascertain containment' conditions (containment pressure, hydrogen concentration and containment water level) during the course of an accident.
Specifically, this change installed Auxiliary Equipment Control Panels C 486-1 through C 486-4 in a four-bay configuration inside the control room.
All materials and work procedures complied with approved Q-List spec-ifications.
This change did not create the possibility of any unanalyzed accident, nor increase the probability or consequences of any previously analyzed accident. The margin of safety as re-lated to the health and safety of the public was not reduced.
79-1078 This change provided emergency power to 42 KW of pressurizer heaters
't (ANO-1) to supplement existing emergency bus powered proportional heater (84 KW rated) to bring the total to-126 KW worth of pressurizer heaters on each of the two diesel generator buses.
This modifi' cation will ensure the capability of natural circulation (i.e., establish and maintain) by providing an assured power supply to the minimum number of pressurizer heaters (126 KW).
Refer to NUREG-0578 (item 2.1.1) for natural circulation. This change is a TMI modification requiring post-implemen-tation review by NRC.
79-1081 This change provided for pressure regulation for the reactor building (ANO-1) vent header to prevent overpressurization of the waste gas surge tank.
This change did not increase the possibility of any accident as analyzed in the FSAR, nor did it increase the probability or consequences of any accident unanalyzed.
The margir of safety as related to the public health and safety was not decrease.d as this change did not increase the frequency of release of gaseous discharges.
Design Change Number Cont'd DESCRIPTIVE
SUMMARY
CONT'O 80-1041 This change was a modification of the Penetration Room Isolation Valve (ANO-1)
Auxiliary Control Relay per I.E.Bulletin 80-06.
The two new pushbutton handswitches added in the C-26 control panel met the same specifications as the original handswitches provided with the panel.
Also, the mdunting of those switches did not change the seismic qualification of the panel.
With the addition of the handswitches and seal-in contacts for the auxiliary control relays, this design is more conservative than the previous design in that the penetration valves will remain in their emergency position upon removal of E.S. actuation until operator control is initiated.
80-1042 This change was a modification of CV-2214 letdown cooler isolation valve (ANO-1) and CV-6203 Reactor Building _ Chilled Water Isolation Valve per I.E.Bulletin 80-06.
This change provided a seal in to the control relay upon receipt of E.S. actuation signal and will ensure that the valves remain in their emergency mode upon removal of the actuating signal and/or manual re-setting of the various isolation or actuation signals. The normal mode of control by handswitch will be automatically reinstated upon removal of the E.S. Signal.
This modification did not increase the probability of occurrence or the consequences of an accident or malfunction of equip-ment important to safety previously evaluated in the SAR, nor did it cause.a possibility for an accident or malfunction of a different type than any evaluated previously in the FSAR.
This modification did not reduce the margin of safety as defined in the Unit One Tech Specs.
In summary, this modification was entirely a control wiring change that was more conservative than the previous design in that it will ensure that the valve will remain in the emergency mode upon removal of the E.S.
until operator control is established.
2-77 This change assured that chiller units 2 VCH-3A and 2VCH-3B will have (ANO-1) sufficient cooling water for the condenser half with the higher pressure, that is, the greater requirement for cooling water.
This was accomplished by adding pressure contr611ers to each condenser half of each chiller.
The output from the controllers serves as input to an analog controller l
that will choose the higher input and send it on to the control valve to modulate the flow of water out of the chiller.
In effect this change ensured that water will always be supplied in accordance with requirements of the section having the higher head pressure.
This change did not create the possibility of an unanalyzed accident, nor did it increase the probability or consequences of a previously analyzed accident. The margin of safety as related to the health and safety of the public was i
not reduced.
2-79-498 This change automatically resets relays CR-2, CR-3, CR-4 & CR-5 in the (ANO-2) event of a momentary power. loss to the instrument air control.
The
Design Change Number Cont'd DESCRIPTIVE
SUMMARY
CONT'D reason for this change is that in the initial modification, if coil TR-3 failed during operation of the instrument air compressor, the above four relays would close.
This would disable the low oil pressure switch, high water temperature switch, and the motor oil switch.
This modifica-tion corrected this problem and automatically reset the circuit as initially desired after a momentary power loss.
This change did not create the possibility of an unanalyzed accident, nor increase the probability or consequences of a previously analyzed accident. The margin of safety as related to the health and safety of the public was not reduced.
2-79-119 This change installed a new, additional auxiliary building ventilation (A40-2) exhaust stack radiation monitor for either unit.
The installation consisted of an isokinetic probe installed in the exhaust stack (one per unit), necessary piping (3/4") to the scmpling station, valving, charcoal and carticulate filters, a radiation monitor, pump, and flow indicator.
The radiation monitor was mounted external to the pipe and consisted of a radiation detector, preamplifier and a remote power supply / readout device.
This new system was added to provide additional r
l stack monitoring capability per NUREG-0578, item 2.1.8.b.
This change did not create the possibility of an unanalyzed accident, nor increase the probability or consequences of a previously analyzed accident. The margin of safety as related to the health and safety of the public was not reduced.
79-2006 This change added a tee and isolation valve to 2HBD-120-6" which allowed (ANO-2) for future tie-ins of the ANO Maintenance Facility Building to the ex-traction steam supply.
This change did not create the possibility of an unanalyzed accident, nor incrase the probability or consequences of a previously analyzed accident.
The margin of safety as related to the t
health and safety of the public was not reduced.
79-2030 Per NRC's request, this change replaced the non-UL/FM fire & smoke (ANO-2) detectors in the containment, the electrical penetration rooms, and the diesel generator rooms with UL/FM approved detectors.
Specifically, the 40 non-UL/FM photoelectric detectors in the containment and penetration l
rooms were replaced with UL listed ionization detectors, and the 6 non-UL photoelectric detectors in the diesel generator rooms were replaced with UL listed infrared flame detectors.
This change did not create the pos-sibility of any previously analyzed accident.
The margin of safety as related to the health and safety of the public was not reduced.
70-2056 This change added steam pump and bypass system control to the remote (ANO-2) shutdown panel for the purpose of enabling the operators to prevent
b Design Change Number Cont'd DESCRIPTIVE
SUMMARY
CONT'O excessive cooldown under certain conditions coincident with cor. trol room uninhabitability.
This change did not create the possibility of any un-analyzed accident, nor increase the possibility or consequences of any
'previously analyzed accident.
The margin of safety as related to the health and safety of the public was not reduced.
79-2068 This change allowed plant personnel to analyze sodium levels in the (ANO-2) ' condenser hotwell to determine leakage between circulation water and the secondary side coolant. This did not create the possibility of an unanalyzed accident, nor increase the probability or consequences of any previously analyzed accident.
The margin of safety as related to the health and safety of the public was not reduced.
79-2160 This change replaced the limitorque electric operators with pneumatic (ANO-2) operators on the heater drain pump recirculation valves 2CV-0719 and 2CV-0725.
The purpose of this change was to reduce the valve suscept-ability to vibration damage and possible subsequent failure without affecting the system function. This did not create the possibility of an unanalyzed accident, nor increase the probability or consequences of any previously analyzed accident.
The margin of safety as related to the health and safety of the public was not reduced.
79-2160B The change replaced the limitorque electric operators with pneumatic (ANO-2) operators on the condensate pump recirculation valves 2CV-0662 and 2CV-0663.
This modification also changed the failed position of the valves from " FAIL AS IS" to " FAIL CLOSED".
This was to assure that the valves keep a minimum flow through the pumps to avoid pump damage, and to protect the discharge piping from overpressure. This change did not create the possibility of an unanalyzed accident, nor increase the probability or consequences of any previously analyzed accident.
The margin of safety as related to the health and safety of the public was not reduced.
79-2162 This change added a pressure regulator to the seal water supply line for l
(ANO-2) the heater drain pumps.
The purpose of this change was to eliminate valve cavitation and poor pressure control.
This change did not create the possibility of any unanalyzed accident, nor increase the probability or consequences of any previously analyzed accident.
The margin of safety as related to the health and safety of the public was not reduced.
i l
79-2164 This change installed an acoustical valve monitoring system to provide l
(ANO-2) the operator with an indication of valve open/ closed position on annun-ciator panel 2K10.
NRC required this position indication of the pres-surizer safety valves per NUREG-0578, item 2.1.3a.
This additic 1al l
l
6 Design Change Number Cont'd DESCRIPTIVE
SUMMARY
CONT'D instrumentation will enhance operator performance during a pressure transient and will have no effect on safety systems or their functions.
This did not create the possibility of an unanalyzed accident, nor increase the probability or consequences of any previously analzyid accident.
The margin of safety as related to the health and safety of the public was not reduced.
79-2167 This change removed a trip signal from the proportional heater circuit (ANO-2) breaker to enable the operator to re-energize the proportional heaters if offsite power is lost.
The heaters will provide additional RCS pressura control following a small break LOCA, and are required by NUREG-0578. The capability for the operator to manually load 150 KW of pressurizer heaters on each D.G. following a loss of off-site power and an SIAS signal was originally available.
Operating procedures require that the operator monitor and maintain the D.G. within its load limits. The seven day rating will not be exceeded with the heaters actuated, thus giving ample time to determine loads that can be shed for. continuous operation.
This did not create the possibility of any unanalyzed accident, nor increase the probability or consequences of any previously analyzed accident.
The margin of safety as related to the health and safety of the public was not reduced.
79-2222 This change added to SIAS to CIAS' actuation logic for 31 valves for the (ANO-2) purpose of providing diverse containment isolation.
This change did not create the possibility of any unanalzyed accident, nor increase the probability or consequences of any previously analyzed accident.
The margin of safety as related to the health and safety of the public was not reduced.
80-0-2017 The purpose of this change was to improve the reliability of the pressurizer (ANO-2) spray valve control.
Specifically, this change repl, aced Borg-Warner operations on 2CV4651 and 2CV4652 with limitorque electric operators; four new handswitches were installed on 2C04 and four handswitches on panel 2C80 for control of opening and closing 2CV4651 and 2CV4652; four bistables were installed on 2C21 to supply instrumentation in 2C21 to supply instrumentation signals to the operators (limitorque) when operating in the " automatic" mode.
This change did not create the possibility of an unanalyzed accident, nor did it increase the probability or consequences of any previously analyzed accident.
The e.:rgin of safety as related to the health and safety of the public was not reduced.
80-2021 This change relocated the wide range s 9 am generator level recorder (ANO-2) 2LR-1079 from the mainfeedwater panel 2C02 to the ESF panel 2C17.
The
~
Design Change Number Cont'd DESCRIPTIVE
SUMMARY
CONT'D purpose of this change was to provide S/G 1evels during startups, cooldowns, and following reactor trips.
Before this change, two operators were re-quired to control S/G level during transient conditions, one to read the level recorder and one to operate the valves.
After this change, one operator can safely control the S/G 1evels.
This change did not create the possibility of an upanalyzed accident, nor increase the probability or consequences of a previously analyzed accident.
The margin of safety as related to the health and safety of the public was not reduced.
80 0-2132 This change rerouted the sodium hydroxide add line and fill line to avoid (ANO-2) the Post Accident Sampling System Building construction.
The new location for the two lines to be moved, and the new orientation for the two valves to be rotated will neither increase the-likelihood or consequences of an ac-cident, nor will it decrease the plant's ability to mitigate the consequences L
of an accident.
80-2138 This change involved the addition of heat tracing and insulation of the (ANO-2) 18" vent on the RWT (2T-3).
No system was affected or degraded in any way.
This change was required to prevent the possibility of the RWT vent freezing in winter and to meet the requirements of I.E.Bulletin 80-05.
80-2139 This change involved the addition.of heat tracing and insulation of the (ANO-2) two 2"x 2" vents on top of the Unit 2 sodium hydroxide tank.
No system was affected or degraded in any way.
This change was required to prevent the possibility of the sodium hydroxide vents from freezing in winter and to meet the requirements of I.E.Bulletin 80-05.
80 0-2141 To enhance serviceability, the 1-1/2" ACW copper-steel supply and return (ANO-2) lines to 2VUC-21 were removed and replaced with 1-1/2" copper pipe.
This modification in no way affected a fire system or a fire systems loading, nor did this modification increase the amount or change the type of effluents discharged from the plant relative to limits contained in the Environmental Technical Specifications.
i l
80-2182 This change provided rated fire barriers between redundant cables in the l
(ANO-2)
MCC room, electrical equipment room and switch gear room at elevation 372.
This change did not create the possibility of an unanalyzed accident, nor increase the probability or consequences of any previously analyzed accident.
The margin of safety as related to the health and safety of the public was not reduced.
1 l
Design Change Number Cont'd DESCRIPTIVE
SUMMARY
CONT'D 80-2191 This change added three valves to the gas collection header (Line 2H80-50)
(ANO-2) for the purpose of venting the charging pump 2P36 suction dampers. This change will not create the possibility of an accident that has not already been analyzed, nor will it change the basis for any technical specification.
This change will not create any additional types or quantities of effluents from the plant.
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