ML20137H984
| ML20137H984 | |
| Person / Time | |
|---|---|
| Site: | Byron  |
| Issue date: | 03/31/1997 |
| From: | Kofron K COMMONWEALTH EDISON CO. |
| To: | NRC (Affiliation Not Assigned), NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| BYRON-97-0073, BYRON-97-73, NUDOCS 9704030182 | |
| Download: ML20137H984 (65) | |
Text
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Commonwcahh F4hson Q3mpany.
flyron Generating station
-4 450 North German Church Road b) ton, IL 610109794 Tel 441423454il March 31,1997 LTR:
BYRON 97-0073 FILE:
2.7.611 Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Attention: Document Control Desk
SUBJECT:
Byron Station Units 1 and 2 10 CFR 50.59 Annual Report NRC Docket Nos. 50-454 and 50-455 Pursuant to the requirements of 10 CFR 50.59 (b)(2), Byron Station is providing the required annuai report for Facility Operating License Nos. NPF-37 and NPF-66. This report is being provided for the 1996 calendar year and consists of descriptions and safety evaluation summaries for changes to the facility as described in the safety analysis report. No tests or experiments govemed by paragraph (a) of 10 CFR 50.59 were performed. Also included as part of this report are changes made to features of the fire protection program not previously presented to the NRC Staff.
Please direct any questions regarding this submittal to Laurie Lahti, Regulatory Assurance Department, at (815) 234-5441 extension 2852.
.f d w K. L. Kofr Station Manager Byron Nuclear Power Station KLK/LAUld Attachment cc:
S. D. Burgess, Senior Resident inspector - Byron i
G.F. Dick, Byron Project Manager - NRR
- L}] 3 U
A. B. Be ch, Regione! Administrator - Rlli 0000'G 0
M.T. Lesniak - Ni.A T. R. Munca - Byron SEC W. W. huk - Braidwood 9704030182 970331 ADOCK0500g4 IRI.Npsygggy DR A rniconi nimpany
Byron Nuclear Power Station 10 CFR 50.59 Summary Report 1996 NRC Docket Nos. 50-454 and 50-455 License Nos. NPF-37 and NPF-66 6
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DESIGN CHANGE PACKAGES (DCPs)
{
.i 1.
DCPs 8602952 and 8602953 2.
DCP 9100777 '
- 3.
DCPs 9202950 and 9202951 4.
DCPs 9301913 and 9301914
{
5.
DCPs 9302072 and 9302073 i
6.
DCP 9302414 7.
DCP 9302564 l
- 8.
DCPs 9400183 and 9400184 9.
DCP 9400205 l
- 10. DCP 9400404
{.j
'11. DCP 9500081 12.. DCP 9500108
- 13. DCP 9500109
- 14. DCPs 9500169 and 9500170
- 15. DCP 9500171
' 16. DCPs 9500182 and 9500183
- 17. DCP 9500185
- 18. DCPs 9500200 and 950020I l
- 19. DCP 9500264
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- 20. DCPs 9500265,9500266,9500329, and 9500330
- 21. DCPs 9500291 and 9500408 l
22.- DCP 950031I l
- 23. DCPs 9500334 and 95003'>5 1
- 24. DCP 9500350
- 25. DCP 9500352 -
]
- 26. DCP 9600179
- 27. DCP 9600225 l
3 i-SETPOINT/ SCALING CHANGES (SSCRs)
I 1.
SSCRs96-013 and 96-014 3-UFSAR CilANGES (Drafi Resisjon Packangs) l.
5.
8.
9.
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UFSAR CliANGES (Drafi Resision Pack _ ages)(Continued)
- 22. UFSA.R DRP 6-083
Eire Protection Report FDRPs (Fire Protectio.n Draft Revision Packaces) 1.
FPR FDRP 16-030 2.
FPR FDRP 17-012 3.
FPR FDRP 17 032 1
4.
FPR FDRP 17-037 Other Channes 1.
Administrative Technical Requirements Amendment 10 2.
Post-Weld Heat Treating Heater Stuck in Steam Generator Tube During Sleeving Process 3.
In Situ Pressure Testing of Steam Generator Tubes 4.
Steam Generator Operation With Sleeve Stabilizers Installed In Insenice Tubes j
5.
Steam Generator Operation with a Foreign Object l
3
pesien Chance Packaecs (DCPs) 8602952 and 8602953 DESCRIPTION:
DCPs 8602952 and 8602953. Wed the resistance temperature detector (RTD) bypass manifold piping on all four reactor coolant loops n,r Units 1 and 2. This allowed replacing the direct-immersion, single-clement RTDs with thermowell-mounted, dual-clement, fast-response RTDs. The hot-leg scoops were modified to accept new thermowells that are positioned to provide an average temperature reading for each scoop. The cold-leg RTD bypass penetration nonic were modified to accept the replacement RTD.
The replacement RTDs are placed in cach of three existing hot-leg scoops and in the cold-leg penetration of each loop. One element of each RTD is active; the other serves as an installed spare. The three hot-leg temperature signals arc electronically averaged in the reactor protection system (RPS) to produce a representative hot-leg temperature.
Replacing the RTD bypass piping / components with the thermowell-mounted RTDs eliminates a significant radiation source, as well as a source of reactor coolant system (RCS) leakage. Also, the design allows a faulty RTD to be replaced without breaching the RCS pressure boundary.
SAFETY EVALUATION
SUMMARY
1.
The probability of an occurrence or the consequence of an accident or malfunction of equipment important to safety as previously evaluated in the UFSAR is not increased. Temperature measurement inaccuracies caused by imbalances in the scoop sample flow are climinated because the hot-leg RTDs are mounted directly in the scoops. With the thermowells welded into the existing RCS hot & cold leg nonles, and the climination of the bypass piping, the number of pressure boundary welds is significantly reduced, resulting in a reduced probability of a small break LOCA A1:;c,, the probability of an accident is not increased because the total response time associated with the over-temperature delta-temperature (OTDT) and over power delta-temperature (OPDT) trip functions remains less than or equal to the 8-second response time previously modeled in the safety analysis.
The consequences of an applicable UFSAR Chapter 15 accident are not increased because the distribution of time responses for OTDT and OPDT does not result in a minimum departure from nucleate boiling (DNB) ratio lower than the safety analysis limit or a fuel centerline melt.
Superheated steam releases are unchanged. The probability of a malfunction of equipment important to safety is not increased because of the compatibility of the 7300 electronic hardware to the original equipment. The capability of the RPS to initiate a reactor trip is not affected. Since the thermowells are passive components, there is no failure mode associated with the thermowell. The consequences of a malfunction of equipment important to safety does not increase because an RTD failure does not result in a release of radioactive materials.
2.
The possibility of an accident or malfunction of a different type than any presiously evaluated in the UFSAR is not created because the design basis accident analyses remain bounding.
3.
The modification does not involve a significant reduction in margin of safety. The events that rely on OTDT and OPDT trips have been evaluated. The evaluation concludes that the safety analyses acceptance criteria continue to be met, since the total response time is consistent with the safety analyses. The OTDT and OPDT trips function in the same manner to terminate DNB-related transients. The reliability of the reactor protection is unaffected by this change.
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DCP 9100777 DESCRIPTIOB The modification installed permanent power supplies, condensate drain lines, duct supports, and panel attachments for the Unit 2 control rod drive (CRD) cabinet and instrument inverter cabinet spot coolers located in the Miscellaneous Electric Equipment Room (MEER). The modification was made to make the i
temporary installation of the spot coolers permanent.
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i SAFETY EVALUATION
SUMMARY
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'l.
The probability of an occurrence or the consequence of an accident or malfunction of equipment 1mportant to safety as previously evaluated in the UFSAR is not increased because the supplemental coolers prmide cool air for the CRD and instrument inverter cabinets to reduce i
internal cabinet temperatures and improve component reliability. The modification minimizes j
. component failures in the CRD and instrument inverter cabinets, which lowers the probability of dropped rods or other control rod misoperation accidents. The changes did not adversely affect the operation of any safety systems or equipment important to safety.
2.
The possibility for an accident or malfunction of a different type than any previously evaluated in
- l the UFSAR is not created because the modification did not alter the design basis of any system or i
adversely affect the function of any system or component. New accident scenarios were not I
credible.
3.
The margin of safety, as defined in the basis for any Technical Specification, is not reduced because the MEER toom ventilation design was evaluated and the modification did not affect the area temperature limit for the MEER listed in Technical Specifications. The new non-safety power distribution had no impact on the on-site power distribution systems discussed in the Technical Specifications.
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p_ cps 9202950 and 9202951 DESCRIPTION:
t
' DCPs 9202950 and 9202951 replaced the existing nonic covers on each unit (eight per unit) with lighter,
[
stainicss stect nonic covers constructed by CB&I. The new covers prmide better gasket seating surfaces than the presiously installed covers.
I SAFETY EVALUATION
SUMMARY
l.
The probability of an occurrence or the consequence of an accident or malfunction of equipment t
important to safety as previously evaluated in the UFSAR is not increased because the nonic cover replacement did not affect the fuel handling cranc, its operation, or the mm enent of fuel.
The nonle covers prmide an improved gasket seating surface over the replaced nonic covers and are more reliable against leakage in support of maintaining refueling cavity water level.
2.
The possibility for an accident or malfunction of a different type than any previously evaluated in the UFSAR is not created because the design basis accident analyses remain bounding.
j 3.
The margin of safety, as defined in the basis for any Technical Specification, is not reduced i
because the installation of the new nonic covers did not affect any parameters upon which Technical Specifications are based i
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d DCPs 9301913 and 9301914 DESCRilrl'lON:
These design change packages removed the abandoned in place exhaust fans 1&2VX07C from the lower cabic spreading rooms for easier access to the turbine building exhaust opening fire dampers for future fire damper surveillances. Fan housings and motors were separated from their supporting equipment beam bases Pressure differential switch 1PDS-VX498 and associated tubing and tube track were removed.
Additionally, fan and pressure differential switch electrical cables were cut back to the conduit.
S AFETY EVALUATION
SUMMARY
1.
The probability of an occurrence or the consequence of an accident or malfunction of equipment important to safety as presiously evaluated in the UFSAR is not increased because fans 1&2VX07C, in the lower cable spreading rooms, are not considered capable of causing any design basis accidents, as described in the UFSAR. Remming the fans did not increase the consequences of an accident because the fans were not relied upon to mitigate the consequences of a design basis accident. Remosing the fans did not contribute to increased off-site doses. The probability of a malfunction of equipment important to safety decreased because the potential for the fan to impact adjacent safety related equipment was climinated. The consequences of a malfunction of equipment important to safety do not increase because fans 1&2VX07C were not relied upon to mitigate the consequences of an equipment malfunction. The fans were previously abandoned in place.
2.
The possibility for an accident or malfunction of a different type than any previously evaluated in the UFSAR was not created because removing the fans has no impact on the engineered safety features switch gear room ventilation system. Once the fans were removed, they were not capable of causing any type of accident, presiously analyzed or not.
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3.
The margin of safety, as defined in the basis for any Technical Specification, is not reduced because the change did not affect any parameters upon uhich Technical Specifications are based.
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DCPs 9302072 and 9302073 DESCRIPTION:
The change rerouted seal leakoff from the chemical and volume control system (CV) charging pump to the auxiliary building equipment drain system (WE).
SAFETY EVAL UATION
SUMMARY
1.
The probability of an occurrence or the consequence of an accident or malfunction of equipment important to safety as previously evaluated in the UFSAR is not increased because this component has no effect on the operation of a CV pump or the performance of the pump seals.
The WE pipe directs seal leakoff flow from the pump seal drip pocket to the WE system instead ei the pump bedplate. The overflow hole acts as a backup for the new drain line. The splash shield is an attachment to the drip pocket and is scismically qualified. Based on the function of these new components, the probability of failure of a CV pump is not increased.
The new pipes are supported by new pipe supports and supported at the drip pocket. The seismic loads to the pump from these attached pipes are low and determined to b:: acceptable per the piping stress calculations. A failure of the WE line to drain properly would result in the leakoff water draining via the overflow hole to the pump bedplate.
2.
The possibility for an accident or malfunction of a different type than any previously evaluated in the UFSAR is not created because the design change is for housekeeping concerns and has no affect on the operation of the pump. Seal leakage occurs at pump startup and also afler the seals wear before they can be replaced. These lines drain directly to the equipment drain system instead of collecting in the pump bcdplate. The potential of a drip pocket filling to a level high enough to allow this water to leak into the oil is minimized by the installation of the overflow holes. Therefore no new failure modes are created.
3.
The margin of safety, as defined in the basis for any Technical Specification, is not reduced because the change did not affect any parameters upon u hich Technical Specifications are based.
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DCP 9302414
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DESCRWTION:
The modification replaced the Unit I main generator hydrogen seal oil CUNO filters with duplex cartridge filters. This allows filter changes with the seal oil system in senice. The new filters remove j
smaller particles. In addition, a filter differential pressure alarm was added. The fire protection deluge system was changed to prmide coverage of the larger area needed for the new equipment.
SAFETY EVALUATION
SUMMARY
4 ^
i 1.
The probability of an occurrence or the consequence of an accident or malfunction of equipment.
important to safety as presiously evaluated in the UFSAR is not increased because the seal oil e
system continues to operate as originally designed. Reliability is increased because a standby -
. filter was added that can be manually valved in when filter differential pressure increases to the i
alarm setpoint. The deluge system continues to prmide fire protection to the seal oil skid. The l
probability of a main generator / main turbine trip is unchanged. No safety-related systems are 3'
affected.
1
- 2.
The possibility for an accident or malfunction of a different type than any previously evaluated in l
the UFSAR is not created because seal oil system operation and performance remain unchanged.
l No safety systems or systems required to mitigate an accident are affected.
3.
The margin of safety, as defined in the basis for any Technical Specification, is not reduced because no systems or components addressed in Technical Specifications are affected.
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DCP 9302564 PESCRWTION:
DCP 9302564 added additional supports to existing fire protection system piping in the turbine building to conform with standard spacing criteria or approved analyzed conditions.
SAFETY EVALUATION
SUMMARY
1.
The probability of an occurrence or the consequence of an accident or malfunction of equipment important to safety as presiously evaluated in the UFSAR is not increased because the fire protection system continues to be operable for all arcas. Fire barricts are not be derated. The separation prosided by fire barriers and the fire extinguishing capabilities provided by the fire protection systems prevent the spread of the fire and protect plant equipment (including safe shutdown equipment) in other areas. The probability of a design basis fire in the affected areas of the turbine buildmg is unchanged because no new permanent fire loads or hazards are added.
For a design basis fire, the fire protection sprinkler and fire hose systems continue to function as designed to protect equipment and the affected areas. If a piece of equipment in the turbine building malfunctions that would require the need for fire protection, the sprinklers and hose stations would continue to operate as designed to assist in controlling and extinguishing the fire.
2.
The possibility for an accident or malfunction of a different type than any previously evaluated in the UFSAR is not created because the operation of the fire protection system is not affected and any additional loads to category I walls have been analyzed and approved for installation.
1 3.
The mcrgin of safety, as defined in the basis for any Technical Specification, is not reduced i
because the change did not affect any parameters upon w hich Technical Specifications are based.
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DCPs 9400183 and 9400184 '
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DESCRif' TION.
i local pressure indicating gauges were added to the chilled water tanks for the Unit I and 2 containment 7
chiller systems. Existing valves were used as the vent valves above the new pressure gauges, but were i
given new valve numbers. Existing vent valves located below the existing level gauges were also given i
new valve numbers. Installation of the pressure gauges allows pressures to be read locally without
'l installing temporary gauges. They are primarily used for reading local pressure when pressuring the j
chilled water tarik(s).
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SAFETY EVALUATION
SUMMARY
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J 1.
The probability of an occurrence or the consequence of an accident or malfunction of equipment important to safety as previously evaluated in the UFSAR is not increased because the pressure l
indicators provide local pressure indication only and are primarily used to provide local pressure j
indication when pressurizing chilled water tanks. The chilled water system remains intact and l
continues to provide chilled water to the reactor containment fan cooler chilled water coils during i
l normal plant operating conditions. The new piping and pressure indicators are seismically supported.
)
i 2.
The possibility for an accident or malfunction of a different type than any previously evaluated in the UFSAR is not created because the safety design basis analysis remains bounding.
I 3.
The margin of safety, as defined in the basis for any Technical Specification, is not reduced j
because the change did not affect any parameters upon which Technical Specifications are based.
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DCP 9400205 PESCRifmON:
DCP 9400205 replaced the Unit 2 2301 Woodward Governor System with a new 2301 A Woodward Governor System. The new system consists of a reverse acting engine speed 2301 A load sharing and speed control duel dynamics governor, digital reference unit, pulse unit, modified, reverse-acting, EGB-50-P engine-mounted actuator, magnetic pickup high signal selector, two magnetic pickup units used to sense engine speed, and a 125 volt to 24 volt DC/DC converter. It also replaced the existing General Electric HFA relays with Amerace EGP and Kilovac vacuum-scaled relays and added an additional Kilovac relay to perform functions required for the 2301 A.
In addition it added a fast / slow switch and circuitry, which provides the capability of" slow" or " idle" engine starts (slow two step starting) of the dicscl during surveillance testing.
SAFETY EVALUATION
SUMMARY
1.
The probability of an occurrence or the consequence of an accident or malfunction of equipment important to safety as presiously evaluated in the UFSAR is not increased because there is no effect on the capability of the emergency dicscl generators to perform their function of prosiding an independent emergency source of power in the event of a complete loss of ofTsite power. This modification only updates the governor control system with a newer model. The replaced dicsci governor hardware is enmpatible with the original hardware. All the new components have been qualified. The resised system is functionally equivalent to the existing one, although it is expected to be more reliable. No functions or operating characteristics are altered, and there is no effect on the capability of the system to respond to an accident or transient.
2.
The possibility for an accident or malfunction of a different type than any previously evaluated in the UFSAR is not created because the design basis accident analyses remain bounding.
3.
The margin of safety, as defined in the basis for any Technical Specification, is not reduced because the governor is not addressed in the basis for any Technical Specifications.
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DCP 9400404 DESCRIPTION:
4 DCP 9400404 supported installation of the vehicle barrier system. This design change was required to comply with the prmisions of 10CFR73 and NUREG/CR-6190 Volume 1, Revisioni and Volume 11, Revision I for protection against malevolent use of vehicles. Concretejersey barriers were installed around the periphery of an existing security fence for the main plant. Cable was used instead of thejersey barriers in locations that had the potential for underground electrical interferences or that affected the natural site drainage flowpaths. Rod barrier gates were installed at locations where access through the barrier was needed, such as at railroad gates.
SAFETY EVALUATION
SUMMARY
1.
The probability of an occurrence or the consequence of an accident or a malfunction of equipment important to safety as presiously evaluated in the UFSAR is not increased because the buildings and equipment are not affected by the change. The maximum water level near the safety-related buildings i
of power block due to the local Probable Maximum Precipitation (PMP) is 870.9 feet. The plant i
buildings have a floor elevation of 870.0 feet. The structural design of the buildings is such that one-
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foot high curbs are prmided at the openings to buildings housing the safety-related facilities.
Therefore, these buildings and equipment are not affected by local PMP, even after prmiding the concrete barriers along the outer security fence. The addition of the vehicle barrier system prmides the required increased protection against malevolent use of vehicles without impacting any equipment important to safety, directly or indirectly.
2.
The possibility for an accident or malfunction of a different type than any previously evaluated in the UFSAR is not created because this design change does not adversely impact UFSAR accident-related systems, structures, and components (SSCs). The addition of the vehicle barrier system does not introduce any adverse interactions between any SSCs.
3.
The margin of safety, as defined in the basis for any Technical Specification, is not reduced because the addition of the vehicle barrier system does not affect any parameters upon u hich Technical Specification are based.
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DCP 9500081 DESCRIPTION:
A general inspection opening was installed into the shcIl side of the Unit 2 C steam generator on the lower shell barrel near the blowdown line. The inspection opening was installed to remove a loose part in the steam generator.
i SAFETY EVALUATION
SUMMARY
1.
The probability of an occurrence or the consequence of an accident or malfunction of equipment important to safety as previously evaluated in the UFSAR is not increased because the shcIl opening pressure boundary cover and gasket fixture maintain the shell pressure boundary to the i
same degrec as the original configuration. Temporary changes that were made to facilitate installation were also restored to their original condition. A postulated feedwater system line break analysis remains bounding. The inspection opening and blowdown line were installed to ASME code requirements and they are inspected to ensure containment leakage limits are not exceeded.
2.
The possibihty for an accident or malfunction of a difTerent type than any previously evaluated in the UFSAR is not created because the inspection opening cover performs the same function as other inspection opening covers for the shcIl of the steam generators. Failure of the steam generator pressure vessel is not considered to be a plausible accident. The pressure boundary is maintained. The replaced pipinj was installed to meet the original configuration The wrapper plug assemblies are scismic category I and do not contact any steam generator tubes. The design and installation requirements of the wrapper plugs provide assurance that the plugs will remain intact through all operating conditions. The installation process ensured that no other parts of the steam generator, such as the tubes, were affected.
3.
The margin of safety, as defined in the basis for any Technical Specification, is not reduced because ASME Section 111, Class 2 pressure vessel boundaries are retained.
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4 DCP 9500108 pJSCRilrTION:
This change rerouted safe shutdown power cables IDC001, IDC002, and IDC003, for the 125-V engineered safety features (ESF) Battery t il out of fire zone 3.2A-1. These safe shutdown cables were previously protected with a 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> rated fire barrier in fire zone 3.2A 1. Rerouting these cables out of the zone climinated the need for the 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> fire barrier.
This change rerouted safe shutdown power cables !CC001, ICV 001, and ISX001, for the 1 A component cooling, I A chemical and volume co itrol, and 1 A essential service water pumps out of all fire zones where their redundant opposite train safe shutdown cables are located. These safe shutdown cables were previously protected with a 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> rated fire barriers. Rerouting these cables out of the zones climinated the need for the 3-hour fire barrier.
The change repowered motor control centers (MCCs) 131X5 and 132X5 from a different cubicle on their respective ESF buses and reassigned 480-volt compartments on MCCs 132X4 and 132X2. These changes were made to allow safe shutdown loads to be powered from the MCCs after the occurrence of a fire in selected fire zones.
SAFETY EVALUATION
SUMMARY
1.
The probability of an occurrence or the consequence of an accident or a malfunction of equipment important to safety as previously evaluated in the UFSAR is not increased because the passive electrical raceway installed under this change is scismically supported and physically and electrically separated from existing plant conduits, piping and equipment such that it does not affect the failure modes or mechanism of any existing plant systems, structures, and components (SSCs). Similarly, the repowering of MCCs does not affect the failure modes of the plant SSCs.
2.
The possibility for an accident or malfunction of a different type than any previously evaluated in the UFSAR is not created because the electrical raceway installed under this change was designed in accordance with the appropriate scismic and electrical design criteria and it does not impact the operation of any plant SSCs important to safety. Similarly, the repowering of MCCs does not impact the operation of any plant SSCs important to safety. Therefore, no new accidents are created as a result of this change.
3.
The margin of safety, as defined in the basis for any Technical Specification, is not reduced because the change did not affect any parameters upon which Technical Specifications are based.
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DCP 9500109 DESCRIPTION:
This exempt change addressed two issues associated with the Thermal Science incorporated Resolution (Thermolag) Project. The first was to reroute safe shutdown control cables IDOOO6, ID0007 (for pump ID00lPB) and IVX113, IVX114 (for fan IVX01C) out of all fire zones where their redundant opposite train safe shutdown cables are located. These safe shutdown cables were previously protected with a 3-hour rated fire barners. Rerouting these cables out of the zones eliminated the need for the 3-hour fire barrier. The second issue was to rewire the IB auxiliary feedwater (AF) pump control circuit to provide provisions to manually bypass the low-low suction pressure trip during emergency (fire) pump operation.
SAFETY EVALUATION
SUMMARY
1.
The probability of an occurrence or the consequence of an accident or a malfunction of equipment important to the safety as previously evaluated in the UFSAR is not increased because the passive electrical raceway installed under this from existing plant conduits, piping and equipment such that it does not affect change is scismically supported and physically and electrically separated the failure modes or mechanism of any existing plant systems, stmetures and components (SSCs).
Similarly, the rewiring of the IB AF control circuit does not affect the failure modes of the plant SSCs. This change does not influence any of the external events; i.e., tornado, responsible for a loss of nonemergency ac power event, or affect the initial conditions assumed in the accident analysis. The electrical raceways are seismically supported in the Category I areas and the appropriate electrical and physical separation is maintained through out the entire routing.
j Therefore, this change does not afTect the operation or a malfunction of any equipment important to j
safety.
2.
The possibility for an accident or malfunction of a different type than any previously evaluated in the UFSAR is not created because the electrical raceway installed under this change was designed in accordance with the appropriate scismic and electrical design criteria and it does not inmact the operation of any plant SSCs important to safety. Similarly, the rewiring of the IB AF cont ol circuit does not impact the operation of any plant SSCs important to safety. Therefore, no new accidents are created as a result of this change.
3.
The margin of safety, as defined in the basis for any Technical Specification, is not reduced because the change did not afTect any parameters upon w hich Technical Specifications are based.
13
DCPs 9500169 and 9500170 DESCRIPTION:
These changes rerouted safe shutdown power cables (2DC001,2DC002, and 2DC003) for the 125-V engineered safety features (ESP) Dattery 211 out of fire zone 3.2A 2. These safe shutdown cables were presiously protected with a 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> rated fire barrier in fire zone 3.2A-2. This change also rerouted safe shutdown control cables 2DG157,2DG175,2DG222, and 2DG223 out of all fire zones where their redundant opposite train safe shutdown cables are located. Rerouting these cables out of the zone eliminated the need for the 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> fire barrier.
This change rerouted safe shutdown power cables (2CC010,2CV001, and 2SX012) for the 2B component cooling,2 A chemical and volume control, and 2B cssentian senice water pumps out of all fire zones where their redundant opposite train saic shutdown cables are located. This change also rerouted safe shutdown control cables 2DOOO6, 2DOOO7 (for pump 2DO0lPB) and 2VXI 13, 2VX114 (for fan 2VX01C) out of all fire zones where their redundant opposite train safe shutdown cables are located. All of these safe shutdown cabk.i were previously protected with a 3-hour rated fire barriers. Rerouting these cables out of the zones climinated the need for the 3-hour fire barrier.
The change also repowered motor control centers (MCCs) 231X5 and 232X5 from a difTerent cubicle on their respective ESF buses and reassigned 480 volt compartments on MCCs 232XI and 232X2, These changes were made to allow safe shutdown loads to be powered from the MCCs after the occurrence of a fire in selected fire zones.
This change rewired the 2D auxiliary feedwater (AF) pump control circuit to proside provisions to manually bypass the low-low suction pressure trip during emergency (fire) pump operation. It also repowered three components (dicscl generator (DG) governor,86G relay and 20SD valve) for the 2A and 2D DG (2DGolKA and KB) from normal DC control power supply #2 to normal supply #1. This change climinated the reliance on DC control power supply #2 to achieve safe shutdown from the local DG control pancis. Consequently, the existing requirement to protect the cable associated with power supply
- 2 from fire is no longer required.
SAEETY EVALUATION
SUMMARY
1 1.
The probability of an occurrence or the consequence of an accident or malfunction of equipment important to safety as presiously evaluated in the UFSAR is not increased because the passive electrical raceway installed under this change is scismically supported and physically and electrically separated from existing plant conduits, piping and equipment such that it does not affect the failure modes or mechanism of any existing plant systems, structures, and components (SSCs). Similarly, the repowering of MCCs, rewiring the 2B AF pump control circuit, and repowering the components on the local DG pancis does not affect the failure modes of the plant SSCs.
2.
The possibihty for an accident or malfunction of a different type than any previously evaluated in the UFSAR is not created because the electrical raceway installed under this change was designed in accordance with the appropriate scismic and electrical design criteria and it does not impact the operation of any plant SSCs important to safety. Similarly,. the repowering of MCCs, rewiring the 2B AF pump control circuit, and repowering the components on the local DG pancis does not affect the failure modes of the plant SSCs Therefore, no new accidents are created as a result of this change.
3.
The margin of safety, as defined in the basis for any Technical Specification, is not reduced because the change did not affect any parameters upon which Technical Specifications are based.
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i DCP 9500171 t
t pESCRIPTION:
[
t The modification replaced Thermolag fire barrier material with an approved alternate material, Darmatt, i
on some cable conduits. The material was replaced because the NRC disqualified Thermolag. The
(
replacement material provides protection against thermal damage to the safe shutdown cables in the event i
of a fire.
i i
1 SAFETY EVALUATION
SUMMARY
1.
The probability of an occurrence or the consequence of an accident or malfunction of equipment 1
r important to safety as previously evaluated in the UFSAR is not increased because the disqualified fire barrier is replaced with an approved fire barrier. The analyses for the design also verified that j
sufficient margin exists for power cable ampacities and that structural support is adequate.
2.
The possibility for an accident or malfunction of a different type than any presiously evaluated in the l
UFSAR is not created because a fire barrier is used when redundant safe shutdown trains are present
'j in the same fire zone. This satisfies the requirements in 10 CFR 50, Appendix R, Section III, which
{
I allows redundant trains to be separated or protected via a fire barrier material.
i 3.
The margin of safety, as defined in the basis for any Technical Specification, is not reduced because f
i.
the fire barrier is not addressed in the bases for any Technical Specification.
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DCPs 9500182 and 9500183 PESCRIPTION:
The modification replaced some reactor vessel level indication system (RVLIS) probes with a new model probe because of connector failures in the old model probes. Future probe replacements will also be to the new model probe. The replacement probe uses a single 40-pin connector for easier connection and disconnection. The 40-pin connector replaced the existing eight 5-pin connectors at the probe. The bundle of eight 5-conductor cables that ran from the probe to the reactor head connector plate was I
replaced with one 40-cond ictor cable. The new cable transitions back to 8 cables at the reactor head connector plate. The new transition cable uses smaller diameter conductors, therefore, two load dropping resistors in the RVLIS heater control circuit were removed.
SAFETY EVALUATION
SUMMARY
1.
The probability of an occurrence or the consequence of an accident or malfunction of equipment important to safety as previously evaluated in the UFSAR is not increased because the replacement RVLIS probes utilize the same pressure boundary assembly (Graylock flange) as the existing probes, therefore, the change did not adversely afTect the reactor coolant system pressure boundary. The new RVLIS probes and cables have been emironmentally and seismically qualified for post-accident senice and perform the same function as the old components. No systems or components required to mitigate an accident were adversely affected. The new RVLIS probes were designed to be more reliable av3 are less likely to fail. The modification did not adversely affect any equipment important to safety.
2.
The possibility for an accident or malfunction of a different type than any previously evaluated in the UFSAR is not created because the changes did not alter the design basis of any system or adversely affect the function of any system or component. New accident scenarios or malfunctions are not credible.
3.
The margin of safety, as defined in the basis for any Technical Specification, is not reduced because the change did not affect any parameters upon which Technical Specifications are based.
16 I
DCP 9500185 DESCRliTION:
This exempt change addressed the following issues associated with the Thermal Science Incorporated (Thor.nolag) Resolution Project. The change repowered three components, diesel generator (DG) governor, 86G relay and 20SD valve, for the 1 A and IB DG (IDG0lKA and KB) from normal DC control power supply #2 to normal supply #1.
This change eliminated the reliance on DC control power supply #2 to achieve safe shutdown from the local DG control panels. Consequently, the existing requirement to protect the cable associated with power supply #2 from fire is no longer required.
t SAFETY EVALUATION
SUMMARY
1.
The probability of an occurrence or the conscquence of an accident or malfunction of equipment important to safety as previously evaluated in the UFSAR is not increased because this change does not add any flammable material or new ignition sources to the plant or adversely affect the safe shutdown of the plant as a result of a fire.
2.
The possibility of an accident or malfunction of a different type than any previously evaluated in I
the UFSAR is not created because this change does not impact the safe shutdown operation of the 1 A or IB diesel generators. Therefore, no new accidents are created by this change.
3.
The margin of safety, as defined in the basis for any Technical Specification, is not reduced because the change did not aficct any parameters upon which Technical Specifications are based.
1 1
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p_CP 9500200 and 9500201 DESCRIIrTION:
The purpose of this change was to climinate pressure locking concerns with valves 1/2SI8811 A/B as identified in NRC Information Notice 95-14 and Generic Letter 95-07. The scope included installing relieflines and relief valves from the bonnet of valves 1/2S!8811 A/B to the downstream piping. This enables relief of abnormally high pressure in the valves to ensure that they will open when required during switchover from the cold leg injection to the cold leg recirculation phase following a loss-of-coolant accident.
i SAFETY EVALUATION
SUMMARY
1.
The probability of an occurrence or the consequence of an accident or malfunction of equipment important to safety as previously evaluated in the UFSAR is not increased because there is no change to the function of valves 1/2S18811 A/B. The containment isolation function of the valves is not adversely affected. The reliability of the valves is improved by climinating pressure locking concerns.
2.
The possibility of an accident or malfunction of a different 13pc than any previously evaluated in the UFSAR is not created because the new reliefline and relief valve have been scismically qualified.
The reliefline piping is classified as high caergy; however, breaks are not postulated for piping i inch and under. Failure of the relief valve to open would result in a system design consistent with the existing design. Failure of the relief valve to close would have no adverse impact since containment isolation would continue to be prosided by the 1/2SI8811 A/B valve disc.
3.
The margin of safety, as defined in the basis for any Technical Specification, is not reduced because the function of valves 1/2S1881 t//B is not changed The valves are required for emergency core cooling system operability per Technical Specifications 3/4.5.2 and 3/4.5.3 and are listed as containment isolation valves in Technical Specification 3/4.6.3. By climinating pressure locking concerns, the reliability of the valves to perform their emergency core cooling system function is improved. In addition, the containment isolation function of valves 2S18811 A/B is not changed.
I 18
i DCP 9500264 DESCRIPTION; DCP 9500264 rerouted the steam generator blowdown sample drain line directly to the 300-gallon hotwell tank and installed a check valve and liquid drain trap in the line to prevent flow through the line in the event of hotwell tank pressurization or air inicakage into the hotwell. Connections were installed to allow a temporary crosstic to the Unit 2 hotwell tank. A Unit 2 check valve was removed, and a pipe was j
enlarged from 1-inch diameter to 2 inches. By routing the sample water to the hotwell tank, the water is
)
recycled instead of routed to the floor drains for eventual disposal as radwaste. This reduces the need for replacement demineralized water. This system was also be used to replace an existing pump system, which required frequent monitoring to operate and caused pump trips.
SAFETY EVALUATION
SUMMARY
1.
The probability of an occurrence or the consequence of an accident or malfunction of equipment imponant to safety as presiously evaluated in the UFSAR is not increased because the drain line is seismically supported and does not tie into any safety system or afTect safety system operation.
2.
The possibility for an accident or malfunction of a different type than any presiously evaluated in the UFSAR is not created because the drain line does not tie into any safety system and does not add to the possibility of an accident. Grab samples can be routed to the sample sink and to the floor drains, if needed, in the event of a loss of the drain line. The existing drain systems also remain installed to proside water removal. The new drain system is designed to operate with flow parameters of existing sample systems and will drain the sample flow to the blowdown condenser hotwell tank. The lines are scismically supported to prevent potential impact on auxiliary buildmg safety-related equipment.
3.
The margin of safety, as defined in the basis for any Technical Specification, is not reduced because the change did not affect any parameters upon which Technical Specifications are based.
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DCPs 9500265. 9500266. 9500329. and 9500330 DESCRIIrFION:
These DCPs installed an additional sample probe for the off gas sample system monitors IRE-PR027J and 2RE-PR027J. The probes are located on the steam jet air ejector (SJAE) exhaust line, and they sample SJAE cfiluent. The original probes located on the common SJAE/ hogger / gland steam condenser lines can be isolated with a manual valve and can be valved-in as necessary. The new sample probe is not isokinetic.
SAFETY EVAL _LJATION S.UMMARY:
1.
The probability of an occurrence or the consequence of an accident or malfunction of equipment important to safety as presiously evaluated in the UFSAR is not increased because these radiation monitors do not mitigate the conscquences of a stcam generator tube leak / rupture. The monitors continue to proside input to determine if there is a steam generator tube leak and to determine the location of a Icak. The monitor interlocks are not changed by this design change. The interlocks continue to pctform their function of swapping to the off gas filter trains on a high radiation signal.
Failure of the probes will not initiate a steam generator tube leak. The probability of a steam generator tube leak / rupture does not increase.
2.
The possibility for an accident or malfunction of a difTerent type than any presiously evaluated in the UFSAR is not created because the UFSAR accidents remain bounding. The new sample location measures activity in the secondary loop more accurately. This should allow quicker identification of steam generator tabe leaks and allow trending and action before a tube rupture occurs.
3.
The margin of safety, as defined in the basis for any Technical Specification, is not reduced because there is no clicct on the plant emuent monitors located at the plant vent stack or their capability to l
monitor station gaseous emuents.
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DCP 9500291 and 9500408 QEjCRiirTION:
The purpose of DCPs 9500291 and 9500408 was to install permanent Westinghouse in-mast sipping hardware to the refueling machine for both units to enable the machine to detect failed fuel assemblies.
The scope of the change included the installation of permanent mechanical components to the mast. The in-mast sipping system permits the injection of air into the bottom of the refueling machine mast, collection of the air at the top of the mast, and passage of the air through a radiation monitoring system.
This system prmides a more accurate method for detecting leaking fuel rods.
SAFETY EVAI.UATION
SUMMARY
1.
The probability of an occurrence or the consequences of an accident or a malfunction of equipment important to safety, as previously evaluated in the UFSAR is not increased because there is no change in the function of the refueling machine. The in-mast sipping components are structurally adequate to withstand deadweight and scismic loads. The probability of a fuel handling accident is not increased. In addition, the tubing and tube supports can withstand the hydraulic drag forces resulting from the rnotion of the mast through the refueling canal water. The ability of the refueling machine to perform fuel handling operations is not changed.
2.
The possibility for an accident or malfunction of a ditTerent type than any previously evaluated in the UFSAR is not created because the in-mast sipping components have been qualified to withstand required loads. Any mast modification hardware that is submerged in the refueling cavity water during operation is constructed of 300 series stainless steel or another approved material. Though the actual in-mast sipping testing process is outside the scope of this change, engineering evaluation determined that there will be no boiling in the fuel assembly as it is suspended in the enclosed refueling mast during the test. Fuct assembly integrity is maintained during and after the in-mast sipping process. In addition, the in-mast sipping system does not present a criticality safety issue 3.
The margin of safety, as defined in the basis for any Technical Specification, is not reduced because this function of the refueling machine is not changed. The scope has no impact on Technical Specification 3/4.9.6, which prmides the operability and capacity and load limit requirements for the refueling machine 21
DCP 9500311 DESCRIPTION:
DCP 950031I replaced the inflatable Presray reactor cavity boot seal with a non-inflatable seal manufactured by NES. The NES scal requires less time to install, and it does not require nitrogen pressure to inflate and provide a seal.
SAFETY EVALUATION
SUMMARY
1.
The probability of an occurrence or the conscauence of an accident or malfunction of equipment important to safety as previously evaluated in the UFSAR is not increased. The NES reactor cavity scal provides a good scal of the reactor cavity through compression of the rubber material.
The J-bolts are analyzed for strength and attach firmly to the reactor vessel flange. Thi.
possibility of a loss of scaling due to deflation of the boot is climinated because the NES seal is not inflated. In the event of a fuel assembly drop on the scal, only localized damage could occur if the assembly fell on thejoint area of two compression plates or damaged a J-bolt.
The reactor cavity seal does not affect the fuel handling crane, its operation, or the movement of fuel, and it has no direct or indirect interface with the fuct handling equipment. The probability of a fuel handling accident is unchanged. Following a fuel handling accident in the reactor core or spent fuct pool area, all radiation monitors, exhaust inlets and ventilation systems, and other required systems continue to function as designed to mitigate the potential radioactive release.
The cavity seal is evaluated for the applicable loading conditions to maintain refueling cavity water level. The NES scal is designed to remain in place during refueling processes and is analyzed for strength and seismic movement. The loss oflevel in the refueling cavity due to reactor cavity scal leakage presents no new consequences, than aircady analyzed, regardless of which seal is used.
2.
The possibility for an accident or malfunction of a different type than any previously evaluated in the UFSAR is not created. The NES cavity seal provides a seal for the reactor cavity. The NES scal, however, is not inflated and removes the possibility of scal Icakage due to loss of nitrogen or leak in the boot inflation system. A calculation has determined the reactor cavity seal will not experience catastrophic failure if a fuel assembly were dropped on the scal. Some localized failure and leakage could result at the impact site if adjacent edges of the metal plates were impacted and none of the impact of the force was absorbed by the fuel assembly, howcrer, the i
remainder of the seal will remain intact. This is an improvement over the original seal, w hich would deflate if punctured, causing a loss of the entire seal instead ofjust at the local failure site.
3.
The margin of safety, as defined in the basis for any Technical Specification, is not reduced because the change did not affect any parameters upon which Technical Specifications are based.
4
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DCPs 9500334 and 9500335 plS.C_Rif' TION, This design change rerouted the jacket water cooling supply and return lines to each diesel engine governor oil cooler by connecting the lines to the left bank inlet and outlet cooling water headers, utilizing Cooper Bessemer's recommended tube routing. Old governor cooling lines were removed and pipe taps at existing water supply and return line connections were plugged. The design permits the governor to operate at the temperatures recommended by Woodward Governor, independent of the operating condition of the engine.
On April 21.1995 Cooper-Bessemer issued a 10 CFR Part 21 notification related to an emergency diesel generator (EDG) event at Nine Mile Point. The event involved Division 1 EDG governor failure as a result of overheating due to restrictive cooling water supply tubing to the governor. ' Byron's governors operated with a small cooling design margin. In addition to the Part 21 issue, Byron's governor cooling system was susceptible to air binding. The cooler was located at the high point in the flow circuit with no means to vent the system, such as a vent valve.
SAFETY EVALUATICN
SUMMARY
1.
The probability of an occurrence or the consequence of an accident or malfunction of equipment important to safety as previously evaluated in the UFSAR is not increased because diesel engine reliability was improved by ensuring adequate cooling and venting of the governor oil cooler. As i
a result, the EDG was not adversely affected by this design change. Accident consequences were not increased because improved governor operation and the resulting improved diesel engine reliability does not ad' escly impact oft-site dose. The probability of a diesel engine governor malfunction was reduced by reducing the possibility for governor overheating or air binding.
The rerouted lines were scismically qualified to ensure the dicscl generator was not adversely afTected by this design change and remains operable. This design change did not impact the consequences of an emergency dicscl generator failure, because the diesel generators were designed to meet the single failure cri.erion. The single failure of a governor cooling line on one dicsci engine does not impact the operation of the other emergency dicscl generators.
2.
The possibihty for an accident or malfunction of a different type than any previously evaluated in the UFS AR was not created because the dicsci generators are house ! in individual rooms to prevent the failure of a single dicscl generator from impacting other diesel generators or other safety-related equipment. Improved governor cooling reduced the potential for governor failure from high temperature or air binding. Therefore, the low energy cooling line reroute did not create the possibility of a new type of accident.
3.
The margin of safety, as defined in the basis for any Technical Specification, is not reduced because the change did not affect any parameters upon which Techrical Specifications are based.
23
DCP 9500350 DESCftIIrrION:
The chemical feed (CF) system for the nonessential senice water (WS) system was modified to preside continuous feed of chemicals. Smaller pumps were installed for the WS chemical feed; abandoned circulating water (CW) system chemical feed pumps were removed. Wiring changes were made in the pump control circuits to proside interlocks for manual operations.
SAFETY EVALUATION
SUMMARY
1.
The probability of an occurrence or the consequence of an accident or malfunction of equipment important to safety as previously evaluated in the UFSAR is not increased because the chemical feed system is not an accident initiator and is not required to mitigate an accident. With this change, proper system chemistry is maintained. Continuous feed of biocide at lowcr rates prmides better contro' for biofouling over batch feed. The change has no impact on operation of the senice water systems served by the chemical feed system - CW, WS, or essential senice water (SX). Alternate chemical feed systems have been in place for CW and SX that were evaluated separately prior to their use.
2.
The possibility for an accident or malfunction of a ditTerent type than any previously evaluated in the UFS AR is not created because the CF system is not important to safety and chemical additions to CW, WS, or SX do not affect the operation of these systems or their failure modes.
The interlocks for starting the pumps and automatically tripping the pumps inre no affect on any of the senice water systems that CF serves. Regulating the chemical feed provides improved control over the manual chemical additions.
i 3.
The margin of safety, as defined in the basis for any Technical Specification, is not reduced because the change did not affect any parameters upon which Technical Specifications are based.
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DCP 9500352
_ ESCRIirTION:
D This change allows either main steam or hot reheat steam to be used as the primary steam supply for the main turbine driven feedwater pumps (MFWP). Use of an alternate steam source required changing the calibration of the MFWP governor valves' lift points. Jumpers in the MFWPs speed control cabinet were repositioned to perform the calibration of the governor valve lift points. This change enhances plant secondary performance under abnormal conditions.
S._AJEETY EVALUATION
SUMMARY
A 1.
The probability of an occurrence or the consequence of an accident or malfunction of equipment important to safety as previously evaluated in the UFSAR is not increased because loss of main feedwater supply remains the bounding accident. The change has no impact on any analyzed accident.
2.
The possibility for an accident or malfunction of a different type than any previously evaluated in the UFSAR is not created because loss of main feedwater supply has already been analyzed, and i
it remains the bounding accident. Neither steam source is assumed to function in any accident.
This design change does not adversely impact any UFSAR accident-related systems, structures, and components (SSCs). The addition of an alternate steam supply system does not introduce any adverse interactions between any SSCs.
3.
The margin of safety, as defined in the basis for any Technical Specification, is not reduced because the cluinge did not affect any parameters upon u hich Technical Specifications are based.
25
DCP 9600179 DESCRIPTION:
DCP 9600179 installed an end cap to line IPR 23B 2 and upgraded the line and newly installed end cap to a class IB piping configuration. Containment isolation check valve IPR 002G would not fully isolate and was found to leak by during testing. Dual isolation is required for this containment / airlock penetration.
Dual isolation was met using manual valve IPR 002E (in the closed position) and the newly installed end cap and piping.
SAFETY EVALUATION
SUMMARY
1.
The probability of an occurrence or the consequence of an accident or malfunction of equipment important to safety as previously evaluated in the UFSAR is not increased because the end cap provides an isolation seal that is superior to that of a check valve and dual containment class IB isolation is maintained. The probability of an accident is not changed because the containment penetration seals do not have an impact on the accidents themselves.
2.
The possibility for an accident or malfunction of a different type than any previously evaluated in the UFSAR is not created because the existing manual isolation valve and the newly installed end cap provide dual isolation for the containment / airlock penetration. The end cap and associa:cd j
pipe are installed to and meet class IB requirements and provide superior isolation propertics to j
the installed check valve, which has been determined to have been leaking by.
3.
The margin of safety, as defined in the basis for any Technical Specification, is not reduced because the added end cap and pipe ensure that containment isolation is maintained with no leakage (for check valve IPR 002G), w hich is below the allowable leakage limit.
26
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i DCP 9600225 i
DESCRIPTION:
DCP 9600225 installed an opening in the containment incore (ICI) tunnel hatch. The opening allows water to flow into the tunnel during containment flooding events. The incore tunnel volume may then be taken credit for in the containment maximum flood level analysis.
SAFETY EVALUATION
SUMMARY
}
r I;
The probability of an occurrence or the consequence of an accident or malfunction of equipment '
important to safety as previously evaluated in the UFSAR is not increased. A loss-of-coolant accident (LOCA) results in the most severe containment flooding condition. The ICI hatch -
{
opening has no impact on the probability of any accident because it is not part of the pressure boundary of the reactor coolant system. Its presence mitigates the consequences of the accident.
2.
The possibility for an accident or malfunction of a different type than any previously evaluated in 4
the UFSAR is not created because the exempt change does not alter the function of any safety.
'j system. The effects of filling the incore tunnel on the containment structure, water chemistry and.
emergency core cooling system function have been evaluated. The design basis analyses remain bounding.
l 3.
The margin of safety, as defined in the basis for any Technical Specification, is not reduced. A i
calculation was performed to ensure that flooding the ICI tunnel is not detrimental to the j
containment structure. The effect of a large quantity of water going into the ICI tunnel was.
cvaluated for effect on containment sump pH. Also, with a large mlume of water entering the ICI tunnel, it was necessary to verify that adequate water would be available for the recirculation j
- sump. Calculation S190-01 previously determined that adequate water would exist in the containment sump with the ICI tunnel filled to allow for operators to switchover to recirculation mode during a LOCA. The location and the design of the opening are such that it will not become blocked.
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Setooint/Scaline Chance Recuests (SSCRs)96-013 and 96-014 pESCRIPTION:
These setpoint/ scaling change requests revised Unit land Unit 2 refueling water storage tank (RWST) level high alarm and RWST empty alarms based on engineering review of the RWST level setpoint calculation and emergency procedure for switchover to recirculation. The RWST cmpty alarm was renamed RWST Level LO-3 to provide an initiating alarm for containment spray (CS) pump switchover to the recirculation sump following a loss-of-coolant accident (LOCA). The RWST Level LO-3 alarm was set at 12% level to provide operators time to complete CS pump switchover before reaching the RWST empty level, which requires stopping the CS pumps. Due to recalculation of RWST vortexing and level instrument uncertainty, the RWST empty level was conservatively increased from 5.8% to 7% to pro ide operators indication that the RWST is no longer a reliable suction source for the emergency core cooling system (ECCS) and CS pumps. The RWST level high alarm setpoint was conscrsatively reduced from 97.1% to 96% to preclude overflowing the RWST and to provide additional margin in the maximum containment flooding analysis.
4 SAFETY EVALUATION
SUMMARY
1.
The probability of an occurrence or the consequence of an accident or malfunction of equipment important to safety as presiously evaluated in the UFS AR is not increased because this change provides more time for operators to complete the containment spray switchover to the recirculation sump without necessitating pump shutoff due to reaching the RWST empty level.
The increased RWST empty level setpoint provided more margin against vortexing in the RWST.
The reduced RWST high level alarm setpoint reduced the RWST volume that could contribute to containment flooding following a LOCA. Since these alarms cannot initiate an accident and arc only required following an accident, the probability of an accident is unchanged.
2.
The possibility for an accident or malfunction of a different type than any presiously evaluated in the UFSAR is not created because the changes will ensure that the containment spray pumps will continue to operate during the time they are being transferred from the RWST to the containment recirculation sump. In the event of multiple equipment failures during switchm'er to recirculation, operators will secure pumps still taking a suction from the RWST upon reaching the RWST empty setpoint, which is now at a higher level. This will preclude ECCS and CS pump damage from occurring due to RWST vortexing.
3.
The margin of safety, as defined in the basis for any Technical Specification, is not reduced j
because there are no Technical Specification limits for the RWST level high and RWST empty l
alarms. The Technical Specifications place requirements on the RWST level low and RWST level LO-2 alarms, which were not changed.
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UFSAR Draft Revision Packace 6-002 DESCRIPTION:
The maximum flood level for the essential service water (SX) rooms was revised to correspond to the calculated flood level for the auxiliary building of 19 inches SAFETY EVALUATION
SUMMARY
1.
The probability of an occurrence or the consequence of an accident or malfunction of equipment important to safety as presiously evaluated in the UFSAR is not increased because the capability of the SX system to perform its function is unchanged. The flood water is assumed to come from a crack in the SX piping. The initiators of the crack are unchanged, more conservative leak rates were assumed. Increasing the flood level in the SX pump rooms does not impact the operator's ability to isolate the pump to stop the leak, or the time required to do so. The impact on plant equipment is the same for the 12-inch flood level as the 19-inch flood level. The redundant SX train is unaffected, since the pumps are separated by water tight rooms, consistent with Branch Technical Position (BTP) Section B.3.b.3. Leak detection sumps continue to be available in the SX pump rooms. These leak detection sumps annunciate a high level alarm in the control room, w hich alerts the operators to excessive leakage in a given area. All required responses are the same, regardless of flood level.
l 2.
The possibility for an accident or malfunction of a different type than any presiously evaluated in the UFSAR is not created because the design basis accident analyses remain unchanged. Per j
calculation HELB-8 (Confirmation of Safe Shutdown Capability After Auxiliary Building Flooding), the SX system is a dual-purpose, rnoderate-energy system and, therefore, per BTP 3-1, a single failure in the SX system need not be postulated along with any pipe cracks or breaks.
3.
The margin of safety, as defined in the basis for any Technical Specification, is not reduced because SX system operation is unchanged. There is no impact on the operability of the SX system.
l 29 i
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UFSAR Draft Resision Package 6 008 DESCRIPTION:
This UFSAR resision changed incorrect references to compressed gases stored in containment and deleted reference to hydrogen bottles that are not installed in the auxiliary building.
SAFETY EVALUATION
SUMMARY
1.
The probability of an occurrence or the consequence of an accident or malfunction of equipment important to safety as previously evaluated in the UFSAR is not increased because the use of air instead of nitrogen to supply the power-operated relief valves (PORVs) has been previously evaluated in the UFSAR as being acceptable. Also, operation of the volume control tank (VCT) with hydrogen from the gaseous waste system has been evaluated in the UFSAR and was found to be acceptable.
2.
The possibility for an accident or malfunction of a difTerent type than any presiously evaluated in the UFSAR is not created because the resisions to UFSAR Table 3.5 10 do not adversely affect any systems, structures, and components. Use of air for operation of the PORVs has been evaluated presiously in the UFSAR and Subsection 3.9.3 of the SER as being adequate to ensure that the PORVs are capable of performing their design functions during accident conditions.
Operation of the VCT with hydrogen from the gaseous waste system instead of the hydrogen source from the 1850 standard cubic feet bottles stored in the auxiliary building has been evaluated in the UFSAR and was found to be acceptable.
3.
The margin of safety, as defined in the basis for any Technical Specification, is not reduced because the change did not affect any parameters upon which Technical Specifications are based.
i 30
UFSAR Draft Resision Packace 6-013 DESCRIIrTION:
r This UFSAR revision reflects the results of a reanalysis of the inadvertent emergency core cooling system (ECCS) actuation at power accident.
SAFETY EVALUATION
SUMMARY
1.
The probability of an occurrence or the consequence of an accident or malfunction of equipment important to safety as previously evaluated in the UFSAR is not increased because the changes in assumptions for the reanalysis provide for a conservative analysis of the pressurizer overfill scenario. The results of the reanalysis show that the reactor coolant system pressure boundary remains isolable once the source of the ECCS flow is terminated. For the pressurizer overfill scenario, the pressurizer power +perated relief valves (PORVs) allow relief of system pressure i
and prevent the pressurizer from filling with water. These ensure that operators can control system pressure and maintain it within the design pressure of the reactor coolant system piping.
One PORV is adequate to control pressure following the transient. In addition, the departure from nucleate boiling scenario maintains reactor coolant system temperatures such that fuel cladding integrity is not affected.
2.
The possibility for an accident or malfunction of a different type than any previously evaluated in l
the UFSAR is not created because the event is already evaluated in the UFSAR. Only new assumptions are being used to assure that a pressurizer overfill scenario has been analyzed conservatively.
l 3.
The margin of safety, as defined in the basis for any Technical Specification, is not reduced i
because the departure from nucleate boiling ratio limits are met and the water relief through pressurizer safety valves is precluded by relief through the pressurizer PORVs.
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UFSAR Draft Revision Packane 6-014 i
s l'
DESCRifrrlON:
This revision deletes the description of calibration whadalogy for reactor containment fan cooler
' (RCFC) inlet and outlet dew point monitor loops.
SAFETY EVALUATION
SUMMARY
i 7
l 1
i' i 1.
The probability of an occurrence or the consequence of an accident or malfunction of equipment i
important to safety as proiously evaluated in the UFSAR is not increased because there is no cffect on equipment failure and no effect on plant operations with the deletion of the methodology as described in the UFSAR for the calibration of RCFC dew point temperature instrumentation.
l 2.
The possibility for an accident or malfunction of a different type than any previously evaluated in the UFSAR is not created because there are no accidents impacted by the calibration methodology l
used for the dew point indicating loop since the accuracy of dew point is not needed to fulfill the intended function of the dew point indicating loop.
4 3.
The margin of safety, as defined in the basis for any Technical Specification, is not reduced because the change did not affect any parameters upon whici. Technical Specifications are based.
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UFSAR Draft Rnision Packane 6-036 r
DESCRIPTION:
This UFSAR revision reflects the as-built configuration of thejacket water cooling system standpipe for I
the emergency diesel generators.
l SF TY EVALUATION
SUMMARY
l l
1.
The probability of an occurrence or the consequence of an accident or malfunction of equipment.
i important to safety as presiously evaluated in the UFSAR is not increased because the change j
does not represent physical changes to the plant or changes to the way the plant operc.s. The r
changes are editorial in nature and have no impact on plant operations.
2.
The possibility for an accident or malfunction of a different type than any previously evaluated in the UFSAR is not created because the change is to clarify the design basis description for the jacket water standpipe. Supporting information for the changes were retrieved from previous
. design files or recreated from calculations and other design information transmittal.
j i
3.
The margin of safety, as defir~! in the basis for any Technical Specification, is not reduced because the change did not afTect any parameters upon which Technical Specifications are based.
I 33
I i
'. UFSAR Draft Resision Package 6-038 1
pfF,SCRIIrrlON:
This UFSAR resision deletes references to the standby hydrogen tanks since the tanks are not used. The j
. changes allow the regulators to receive pressure but to be isolated on the downstream side to prevent -
t; excessive operation of valve.
S AFETY EVALUATION
SUMMARY
1.
The probability of an occurrence or the consequence of an accident or malfunction of equipment important to safety as presiously evaluated in the UFSAR is not increased because the reserve standby tanks are not used. liydrogen supplied from vendor tanker trucks provides the capacity needed for plant operations. Isolation of the reserve header has no impact on plant operations.
6 j
2.
The possibility for an accident or malfunction of a different type than any previously evaluated in the UFSAR is not created because the hydrogen remains available to perform required functions.
Removal of the reserve hydrogen bottics reduces leaks on the system. The reliability of the regulators is improved.
i 3.
The margin of safety, as defined in the basis for any Tech. ical Specification, is not reduced '
because the hydrogen supply source is not addressed in the basis for any Technical Specification.
l i
4 34
UFSAR Draft Revision Packanc 6-04)
DESCRiirTION:-
This UFSAR revision deletes the discussion of response time for the containment sump level transmitters, containment level transmitters, and the containment pressure transmitters. The response time information.
in the UFSAR is based on vendor specifications and it is not required per Regulatory Guide 1.97.
SAFETY EVALUATION
SUMMARY
1.
The probability of an occurrence or the consequence of an accident or malfunction of equipment important to safety as presiously evaluated in the UFSAR is not increased because the removal of discussion has no bearing on the function, operation or testing of the loops. The probability of a line break inside containment is not increased. The function or operation of the instrument loops to provide adequate and timely information to the operators is not adversely impacted, and no other safety equipment is affected.
2.
The possibility for an accident or malfunction of a different type than any previously evaluated in the UFSAR is not created because the function, operation or testing of the affected instrument loops is not affected and plant operation is unaffected.
3.
The margin of safety, as defined in the basis for any Technical Specification, is not reduced because the manner in which the function or operation of the instrument loops to provide adequate and timely information to the operators is not impacted and no other safety equipment is affected.
35
UFSAR Draf) Revision Packace 6-042 PESCRJI* TION:
This UFSAR revision deletes text in the UFSAR regarding applicability of Regulatory Guide 1.140 to the gaseous waste (OW) system. GW is not a plant atmospheric cicanup or HVAC system and does not contain any filtration units, such as high efliciency particulate air filters or charcoal adsorbers; therefore the GW system is not subject to the requirements under Regulatory Guide 1.140.
SAFETY EVALUATION
SUMMARY
1.
The probability of an occurrence or the consequence of an accident, or malfunction of equipment important to safety as previously evaluated in the UFSAR is not increased because the gaseous waste processing system, as discussed in Chapter i1, continues to perform its designed function of remosing fission product gases from the reactor coolant. Since the change dm not alter the functional requirements of the GW system nor its subsystems or components, the probability of the decay tank or associated piping failure is unaffected. The UFSAR resision removes inaccurate description of the GW design in reference to Regulatory Guide 1.140. This text resision clarifies the applicable Regulatory Guide for GW and has no impact to the function and operations of any equipment important to safety.
2.
The possibility for an accident or malfnaction of a different type than any previously evaluated in the UFSAR is not created because this text resision does not alter the functional requirement of the GW system or any other subsystems. Regulatory Guide 1.140 does not apply for the GW system. Additionally, there is, no impact tu the function and operations of any other equipment important to safety.
3.
The margin of safety, as defined in the basis for any Technical Specification, is not reduced because the change did not affect any parameters upon which Technical Specifications are based.
l 36
UFSAR Dra_f] Revision Package 6-046 DESCRIPTION:
This UFSAR revision adds information for ZlRLO fuel cladding Westinghouse VANTAGE + and Performance + fuel features, peak linear power, improved integral fuel burnable assembly patterns, and removes the powcr spike factor def;cription.
SAFETY EVALUATION
SUMMARY
1.
The probability of an occurrence or the consequence of an accident or malfunction of equipment important to safety as previously evaluated in the UFSAR is not increased because the use of ZlRLO cladding and VANTAGE + and Performance + fuel features has been shown to meet all licensing and design basis acceptance criteria. The peak linear power density revision reflects a change n; the referenced parameter used in the Westinghouse analysis. The climination of the power spke factor due to fuel densification reficcts a resised Westinghouse reload analysis methodology that has been approved by the NRC. Since all the design criteria and standards continue to be met for the fuel-related changes, the consequences of an accident is not increased.
2.
The possibility for an accident or malfunction of a different ty[x: than any presiously evaluated in the UFSAR is not created because the changes are consistent with NRC-approved methodology.
The peak linear power density resised reference corrects a change in the referenced parameter as used in the Westinghouse analysis. No new failure mechanism has been created nor will these changes cause the fuel or any other systems, structures, and components (SSCs) to exceed any licensed limit.
3.
The margin of safety, as defined in the basis for any Technical Specification, is not reduced because the current fuel design recognized in the Technical Specification is the VANTAGE-5 design. VANTAGE + or Performance + fuel meets the design criteria of the VANTAGE-5 fuel design and, thus, are in agreement with the Technical Specification. Each reload core is evaluated using NRC-approved methodologies and fuel rod design models and methods. These methodologies also include evaluation of the core peaking factors and core average linear heat effects.
37
r UFSAR Draft Revision Packane 6-047 j
r i
DESCRIPTION; This UFSAR change reflects the reactor cavity ventilation subsystem design bases, which limits the i
normal maximum exhaust air temperature from the reactor cavity and annulus areas to 124.7 'F.
SAFETY EVALUATION
SUMMARY
l r
1.
The probability of an occurrence or the consequence of an accident or malfunction of equipment important to safety as previously evaluated in the UFSAR is not increased because the change:
revises the UFSAR to reflect the equipment qualification (EQ) design temperature for the reactor l
cavity ventilation system. The change does not affect the operation of any plant systems. The -
(
equipment imponant to safety in the reactor cavity areas has been qualified for the maximum
{
normal temperature of 124.7 *F.
i 2.
The possibility for an accident or malfunction of a different type than any previously evaluated in l
the UFSAR is not created because the change does not adversely affect the function of any l
systems or components. Reference to the EQ design temperature for the reactor cavity ventilation system does not create any new accident scenarios.
j 3.
The margin of safety, as defined in the basis for any Technical Specification, is not reduced because the reactor cavity ventilation system design basis is not addressed in the Technical Specifications.
38 i
)
c i
UFSAR DraA Roision Packanc 64)50 DESCRWTION:
l i
This UFSAR revision reflects the routine practice during of full core omoads during refueling to facilitate fuel shuming and reactivity management concerns. Full core omonds were discussed in the UFSAR, but
~ it was determined that clarifications should be made in response to NRC Information Notice 95-54 and other related information.
j SAFETY EVALUATION
SUMMARY
j 1.
- The probability of an occurrence or the consequence of an accident or m6 function of equipment j
important to safety as presiously evaluated in the UFSAR is not increased because the i
clarifications to the description in the UFSAR regarding core omoad practice do not affect any equipment operations or any accident analysis assumptions. This clarification does not represent a change to the basis of what has been previously analyzed, resicwed, and approved.
l 2.
The possibility for an h... dent or malfunction of a different type than any previously evaluated in the UFSAR is not created because the change is only a clarification for the routine practice of full i
core omoads during refueling outages. This mode of omoad during refueling has been -
previously reported to the NRC in the Byron high density rerack license amendment request, and the NRC has approved the installation of the high density storage racks in the spent fuel pool.
However, the routinc offload practice was not clearly identified and described in the UFSAR.
3.
The margin of safety, as defined in the basis for any Technical Specification, is not reduced l
because this change does not affect any operating or safety limits stated in the Technical Specifications or its Bases.
P i
3.
a e
39
l UFSAR Draft Resision Packane 6-054 DESCRIPTION:
This UFSAR resision to Appendix A states compliance with Resision 3 of Regulatory Guide 1.118 with exceptions to the regulatory position on the use of circuit alterations during safety system testing.
SAEETY EVALUATION
SUMMARY
1.
The probability of an occurrence or the consequence of an accident or malfunction of equipment important to safety as presiously evaluated in the UFSAR is not increased because the UFSAR revision has no impact on plant operations during all operating modes and no accidents are affected by the exceptions taken to the regulatory guide for the safety system testing.
2.
The possibility for an accident or malfunction of a different type than any presiously evaluated in the UFSAR is not created because there are no new administrative, procedural, or operational controls necessary to implement the requirements and exceptions taken to this resision. The exception taken reflects the current station testing practices and/or methodology. These alterations are independently verified during both installation and restoration. These practices permit complete functional verification of circuit operation while ensuring the original circuit configuration is maintained.
3.
The margin of safety, as defined in the basis for any Technical Specification, is not reduced because compliance to Resision 3 of Regulatory Guide 1.118 with the exceptions taken does not change the parameters upon which any Technical Specifications are based.
i i
1 40
i UFSAR Draft Resision Packace 64)59 DESCRII'flON:
This UFSAR resision incorporates changes resulting from the two most recent steam generator tube plugging (SGTP) analyses The first SGTP also incorporated positive moderator temperature coefficient (MTC) and reduced thermal design flow (TDF) into the analysis of record.
S AFETY EVALUATION
SUMMARY
1.
The probability of an occurrence or the consequence of an accident or malfunction of equipment important to safety as presiously evaluated in the UFSAR is not increased because all accident analysis consequences results fall within the range of criteria previously evaluated as being acceptable. There is no impact on the NRC issued Safety Evaluation Report supporting the positive MTC/ reduced TDF. No increase in accident probabilities or dose consequences are realized due to the increased steam generator tube plugging analyses. Increasing the steam generator tube plugging percentage does not increase the probability of any analyzed accidents.
2.
The possibility for an accident or malfunction of a different type than any presiously evahiated in the UFSAR is not created because the positive MTC and reduced TDF analyses supporting the technical specification submittal were found acceptable by the NRC in an SER. The impact of each part of the change has been evaluated and was determined to be acceptable with respect to not initiating a new accident. In addition, increasing the steam generator tube plugging percentage does not create a new accidents or malfunction of equipment from what has presiously been evaluated in the UFSAR.
3.
The margin of safety, as defined in the basis for any Technical Specification, is not reduced because the impact of the revised analyses due to increased SGTP, positive MTC and reduced TDF does not change the parameters upon which Technical Specifications are based. As discussed above, all accident probabilities and dose consequences fall within acceptable bounds, and therefore, the margin of safety is not reduced by this UFSAR update.
41 i
i UFSAR Drafi Revision Package 6-060 i
i QESCRIPTION:
1his UFSAR revision reflects the addition of a new section in Appendix A to show compliance with Regulatory Guide 1.160 pertaining to the implementation of the Maintenance Rule.
SArETY EVALUATION
SUMMARY
J 1.
The probability of an oxurrence or the consequence of an accident or malfunction of equipment important to safety as previously evaluated in the UFSAR is not increased because the Maintenance Rule does not affect plant operations and there are no systems, structures, and components being added, removed, or modified.
2.
The possibility for an accident or malfunction of a different type than any previously evaluated in the UFSAR is not created because the Maintenance Rule is a monitoring program that does not affect plant operations or create any new or different failure modes.
3.
The margin of safety, as defined in the basis for any Technical Specification, is not reduced because the Maintenance Rule function does not change the parameters upon which Technical Specifications are based.
42 m.
v
UFSAR Draf1Bnision Packace 6 061 i
I DESCRIPTION:
This UFSAR rnision reflects changes the description for cation and mixed bed chemical and volume control system (CVCS) dcmineralizers.
SAFETY EVALUATION
SUMMARY
1.
The probability of an occurrence or the consequence Of s.n accident or malfunction of equipment important to safety as previously evaluated in the UFSAk is not increased because there are procedural controls in place that ensure a reactivity excursion is not created. In the event of an accident, the CVCS is isolated to contain radioactive materials. The demineralizer vessels and their redns do not affect offsite dose. Since the dcmineralizer beds are not available as a flow path into the reactor coolant system, no safety equipment is affected.
2.
The possibility for an accident or malfunction of a difTerent type than any previously evaluated in the UFSAR is not created because the overall function of the CVCS system is maintained. Resin is selected so that there is no impact on reactivity management; any other accidents are bound by those previously analyzed.
3.
The margin of safety, as defincd in the basis for any Technical Specification, is not reduced because there are no operating limit: affected by the use of difTerent resins in the CVCS dcmineralizer vessels and there is no effect on any parameters upon which Technical Specifications are based.
43
UFSAR Drafi Rnision Packaec 6-065 DESCRIPTION:
This UFSAR revision removes references to specific cable vendors and allows other vendors to be selected.
SAFETY EVALUATION
SUMMARY
c 1.
The probability of an occurrence or the consequence of an accident or malfunction of equipment imponiant to safety as presiously evaluated in the UFSAR is not increased because the changes do not affect plant operations or functions of any equipment used to mitigate the consequence of an accident. The new cables are procured to the equivalent electrical requirements of the construction cable. New cable meets the requirements of Comed standard N-EM-0035.
2.
The possibility for an accident or malfunction of a difTerent type than any presiously evaluated in the UFSAR is not created because the new cables are procured to the equivalent electrical and emironmental requirements as the construction cable.
3.
The margin of safety, as defined in the bat" for any Technical Specification, is not reduced
)
because the change did not affect any paran.eters upon which Technical Specifications are based.
44
UFSAR Draft Resision Packane 6-067 7
L DESCRIPTION:
This change updated the description of compliance Regulatory Guide 1.99, revision 2, to reficct analyses of the material and stress characteristics of the reactor vessel over time. The change also added ASME code cases and heat numbers.
SAFETY EVALUATION
SUMMARY
t 1.
The probability of an occurrence or the consequence of an accident or malfunction of equipment important to safety as presiously evaluated in the UFSAR is not increased because the current analysis is bounded by the NRC's safety evaluation report (SER) for Amendment 37 (NPF-37 and 66) and Generic Letter 8811, The applicability of Regulatory Guide 1,99, resision 2 has been evaluated in the SER. Using the guidance from Regulatory Guide 1.99, the effect of neutron irradiation of the reactor vessel material was calculated to be reasonably conservative and acceptable by the NRC within the above SER. Information was updated to reflect current analysis results.
2.
The possibility for an accident or malfunction of a different type than any previously evaluated in the UFS AR is not created because the calculated effect of neutron irradiation of the reactor vessel material using guidance from Regulatory Guide 1.99, Resision 2, was verified by the NRC within the above SER.
The margin o safety, as defined in the basis for any Technical Specification, is not reduced because r
3.
the change is consistent with Amendment 37. The SER cxplicitly states that the pressure / temperature j
limits were based on Section I of Regulatory Guide 1.99, Revision 2. The additional changes to the UFSAR have no effect on the margin of safety as defined in the basis for any Technical Specification.
45
UFSAR Draft Resision Packace 6-069 DESCRIPTION:
This UFSAR change revises the least negative Doppler power coefficient and the Doppler-only power defect values used in the reload safety evaluation.
SAFETY EVALUATION
SUMMARY
1.
The probability of an occurrence or the consequence of an accident or malfunction of equipment important to safety as presiously evaluated in the UFSAR is not increased because the reload safety evaluation has considered the effects due to revised values of the least negative power coefficient and the Doppler-only power defect, and all fuel mechanical, thermal-hydraulic and transient analysis design criteria continue to be met.
2.
The possibility for an accident or malfunction of a different type than any previously evaluated in the UFSAR is not created because the resised values of the least negative power coefficient and the Doppler only power defect have been considered in each reload safety evaluation. No new single-failure mechanism has been introduced nor will the core operate in excess of design basis operating limits for the safety parameters.
i 3.
The margin of safety, as defined in the basis for any Technical Specification, is not reduced 1
because the change did not affect any parameters upon which Technical Specifications are based.
The reload design has been shown to meet all licensing basis acceptance criteria.
46
l!fSAR Draft RevilpAPgqlsace 6-070 i
DESCRIPTION:
UFS AR Appendix E.21 for Postaccident Sampling (PAS) system is icvised to climinate commitments that were excessive based on the review of regulatory documents requiring a postaccident sampling program.
SAFETY EVALUATION
SUMMARY
1.
The probability of an occurrence or the consequence of an accident or malfunction of equipment important to cafety as previously evaluated in the UFSAR is not increased because the assumptions and conditions evaluated in the accident analysis are not changed. In addition, the responses to an accident as defined in the site's Generating Station Emergency Plan (GSEP) and Emergency Response Procedures (ERP) are not affected by these changes. The changes made to the PAS program affect a limited number of sampling and analytical capabilities that were identified as unnecessary in the course of mitigating an accident and for providing information to the decision process for the protection of the public during an accident.
2.
The possibility for an accident or malfunction of a different type than any previously evaluated in the UFS AR is not created because the sampling and analysis capabilitics that were removed from the program provided only a monitoring function, which was initiated after the accident started. The data generated from these sampling and analysis capabilitics were not being used by the site's GSEP or by the ERPs. The accident analysis described in the UFSAR does not take credit for these capabilitics. The information that could be generated by these capabilities would not be used during j
the mitigation of an accident.
j 3.
The margin of safety, as defined in the basis for any Technical Specification, is not reduced because the changes do not afTect any Technical Specification parameters or their bases. The PAS program is initialized after an accident has occurred and there are no chemistry specification parameters defined or bases described for chemistry parameters under an accident condition.
47
UFSAR Draft Revision Packace 6-081 DESCRIPTION:
This UFSAR change reflects replacement of secondary source assemblics. Each replacement secondary source assembly contains a symmetrical grouping of six secondary source rods.
i SAFETY EVALUATION SUMM ARY:
1.
The probability of an occurrence or the consequence of an accident or malfunction of equipment important to safety as previously evaluated in the UFSAR is not increased because the use of the encapsulated secondary source design (ESSD) does not impose any new performance requirements on the reactor coolant system, therefore, the integrity of the pressure boundary will be maintained. This modification does not affect the initiator of any accident, therefore, the probability of such accidents remains unaffected and the accident analysis contained in the l
UFSAR remains bounding.
The use of the ESSD does not result in a challenge to the fission product boundaries, i.e., fuel cladding, pressure vessel, and containment. The limits imposed by the technical specifications continue to be met. Therefore, the conclusions presented in the UFSAR remain valid such that the radiological consequeaces of an accident are not increased.
2.
The possibility for an accident or malfunction of a difTerent type than any previously evaluated in the UFSAR is not created because plant equipment and performance is not adversely affected by the use of the ESSD. No new failure modes were identified for any system or component important to safety nor has any new limiting failure been identified. Therefore, the possibility of an accident different than any already evaluated in the UFSAR is not created.
i 1
Equipment and system design criteria continue to be met and component and system performance are not adversely affected by the use of the ESSD. There are no direct or indirect effects on safety related equipment. Installation and use of the ESSD does not affect the probability of safety-related equipment malfunctions evaluated in the UFSAR.
The consequences of a malfunction of equipment are bounded by the analyses in the UFSAR.
Onsite and ofTsite exposures are not expected to be increased as a result of the modification and j
no additional radiological consequences are anticipated as a result of any of the accidents analyzed in the UFSAR.
Use of the ESSD does not introduce any new failure modes for any equipment u hich are credible and have not been presiously considered in the UFSAR. No new performance requirements are imposed on any system or component such that any design criterion is exceeded.
3.
The margin of safety, as defined in the basis for any Technical Specification, is not reduced j
because use of the ESSD does not adversely affect any physical parameters or conditions that are addressed in the plant Technical Specifications.
1 J
48 i
UFSAR Draft Revision Packaec 6-082 DESCRIPTION:
This UFSAR change describes operating procedures that are available to ensure boron injection flowpaths are available.
SAFETY EVALUATION
SUMMARY
1.
The probability of an occurrence or the consequence of an accident or malfunction of equipment important to safety as previously evaluated in the UFSAR is not increased because the change does not impact the capability to inject borated water to the reactor coolant system from the boric acid storage tank or refueling water storage tank. All accidents remain bounding.
2.
The possibility for an accident or malfunction of a different type than any previously evaluated in the UFSAR is not created because there is no change ofintent on boration. Several controls are in place to verify adequate boron injection flowpaths are available. Thus, no new accident or malfunction scenarios are introduced.
3.
The margin of safety, as defined in the basis for any Technical Specification, is not reduced because boron injection flowpaths are verified by operating procedures. The capability to inject borated water is not affected.
i i
i 1
44
v
.j i
l UFSAR DraA Revision Packane 6-083 l
DESCRIPTIQN; This UFSAR revision deletes the specific hydrogen gas tempcrature of 108 'F in the main generator.
1 S.AFETY EVALUATION
SUMMARY
-(
i
'i 1.
The probability of an occurrence or the consequence of an accident or malfunction of equipment -
?
imponant to safety as previously evaluated in the UFSAR is not increased because the.
l temperature of the main generator hydrogen will still be operated within the manufacturer's
]
recommended limits. The main generator is not a safety-related system, structure, or component.
j (SSC) and does not affect any safety-related SSC's ability to perform its design functions.
j i
2.
The possibility for an accident or malfunction of a different type than any previously evaluated in the UFSAR is not created because the change only removes the reference to the operating -
l temperature of the hydrogen gas inside the main generator; all alarm limits and trip setpoints remain unchanged.
3.
The margin of safety, as defined in the basis foi any Technical Specification, is not reduced because the change did not affect any parameters upon which Technical Specifications are based.
'I 50
. 2,. _
l
UFSAR Draft Revision Packaec 6-088 DESCRWTION:
This UFSAR was revised to reflect the current configuration and operation of the radwaste systems.
S AFETY EVALUATION
SUMMARY
1.
The probability of an occurrence or the consequence of an accident or maliunction of equipment important to safety as previously evaluated in the UFSAR is not increased because the operation of the waste gas decay tanks or associated piping that are involved with the initiation of waste gas system leak or failure is unchanged. The changes to the waste gas system involve changing the operation of the backup waste gas compressor from automatic to manual. This does not affect the system activity or any other accident assumption. There are no changes to the amounts or types of radionuclides present and no specific operator actions are required to mitigate consequences of this accident. Since the accident analysis assumptions are not impacted by the compressor operation, the other equipment operations remain unaffected. The waste gas decay tanks remain isolated so that only one tank may be released. Therefore, the consequences are not changed.
]
The changes have no efTect on the radioactive liquid waste system leak or failure that could cause a release of the radioactive inventory of the spent resin storage tank or boron recycle holdup tanks. The initiators for these releases are operator error and small cracks that propagate.
Ilowever, operator actions are not credited in the accident. Additionally, the changes do not j
affect the '
ce terms for the radwaste systems so the dose consequences remain bounding.
Since the, age delete references to equipment neither used not required to process waste, the remaining equipment will not be operated in a ditTerent manner. As such, there are no changes to equipment malfunctions or to the activity in the radwaste system, so the consequences are not changed.
2.
The possibility for an accident or malfunction of a difTerent type than any previously evaluated in the UFSAR is not created because none of the changes affects the ability of a system or process to meet ellluent limits. Alternate processing methods are desirable to have the flexibility to best handle cach waste stream so that the activity limits and waste form requirements are met. There are no changes to the source terms, and all effluent limits continue to be met. Operation of the radwaste systems is not an accident initiator.
3.
The Jaargin of safety, as defined in the basis for any Technical Specification, is not reduced because the because none of the changes affects the ability of a system or process to meet efiluent limits arid the changes do not change the parameters upon which Technical Specifications are based.
51
~ UFSAR DraA Raision Packane 6-090 DESCRIPTION:
This UFS AR revision reflects an exception taken to the transient emergency diesel generator (EDG) loading requirements for emergency load scquencing in Regulatory Guide 1.9, Revision 3.
SAFETY EVALUATION SUMAMRl; '
l-
. The probability of an occurrence or the consequence of an accident or malfunction of equipment important to safety as presiously evaluated in the UFSAR is not increased because the increase of the underfrequency EDG time delay does not affect the reliability of the switchyard, SATs or other auxiliary power equipment. The frequency response for a starting sequence does not affect the ability of the EDG to perform safety functions. Increasing the underfrequency EDG time delay and taking exception to Regulatory Guide 1.9 was found acceptab!c because the underfrequency trip is unchanged and there is no effect any of the plant safety equipment.
2.
The possibility for an accident or malfunction of a different type than any presiously evaluated in the UFSAR is not created because the slight frequency transient has no impact on the licensing
. basis accidents. The emergency core cooling system flow rates continue to meet the required design flows during all accident conditions. All other required equipment is expected to operate N mally during the underfrequency transient due to the short duration of the transient and its inconsequential impact on flow rates and current.
3.
The margin of safety, as defined in the baris for any Technical Specification, is not reduced because the change does not adversely impet any of the systems operations or their mitigating functions during accident conditions and doci sot change the parameters upon which Technical Specifications and their bases are based.
\\
i 4
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4
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1 i.
I i
UFSAR Draft Rnision Packame 6-092 i
DESCRIPTION:
This UFSAR revision indicates that the pressurizer backup heaters are energized during normal
- operations.
2 SAFETY EVALUATION
SUMMARY
1.
The probability of an occurrence or the consequence of an accident or malfunction of equipment important to safety as previously evaluated in the UFSAR is not increased because leasing the j
backup heaters energized during plant transients is already addressed in UFSAR Subsection 15.2.8.2. The effects are negligible.
l 2.
The possibility for an accident or malfunction of a different type than any pretiously evaluated in I
the UFSAR is not created because the change is bounded by the safety analysis presented in Subsection 15.2.8.2 that discusses the effects ofleaving the backup pressurizer heaters on during l
plant transients.
t 3.
The margin of safety, as defined in the basis for any Technical Specification, is not reduced
' l' because the change does not adversely impact the assumed mitigating functions et any safety-related systems during accident conditions and does not affect any parameters upon which Technical Specifications are based.
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T i
UFSAR DraA Revision Packame 6-093 l
4
' i DESCRil' TION.
i This UFSAR revision reficcts the instalia' ion of an equipment staging structure adjacent to the errergency t
hatch.
i t
3 SAFETY EVALUATION
SUMMARY
' I 4
~
1.
The probability of an occurroce or the consequence of an accident or malfunction of equipment important to safety as previously evaluated in the UFSAR is not increased because this structure -
i j
does not affect any system's, structure's, and component's (SSC) functions required during l
accident conditions. In addition, the rr.quirements on containment building penetration ::losure and operability ensures that radioactive release resulting from an accident and, therefore, dose.
(
consequence are not increased. The staging structure does not contain any safety-related.
l equipment, nor does it serve as a barrier for offsite dose. Also, this building does not adversely l
affect the personnel hatch.
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2.
The possibility for an accident or malfunction of a different type than any previously evsjuated in i
the UFSAR is not created because this structure does not affect any SSC's functions required l
l during accident conditions or during normal plant operations. The effects of this structure have l
{
no impact on the fuel drop accident in the containment and they do not introduce any differen' i
accident scenarios.
3.
The margin of safety, as defined in the basis for any Technical Specification, is not reduced F
because the change does not adversely impact the assumed mitigating functions of any safety-related systems during accident conditions and does not affect the parameters upon which p
Technical Specifications are based.
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UFSAR Draft Revision Packace 6 099 DESCRIPTION:
This UFSAR change corrects the description of some emergency diesel generator (EDG) alarms and revises mesh size of starting air filters and lubrication oil sampling frequency.
SAFETY EVALUATION
SUMMARY
1.
The probability of an occurrence or the consequence of an accident or malfunction of equipment important to safety as previously evaluated in the UFSAR is not increased because these changes do not have any effects on the initiaiingsenis lea ~ ding t' the listed accidents or the reliability
~
o and availability of the EDG. The EDG is only required to provide emergency power under certain accident conditions and these changes have inconsequential effects on the EDG design functions during accident.
2.
The possibility for an accident or malfunction of a different type than any previously evaluated in the UFSAR is not created because the change regard ng the EDG alarm was a correction c.f the of the order of description about the local alarms. The ;hange to the stated size of the starting air system filters reficcts changes made and results of evaluations which was found acceptable.
Frequency change in the lubrication oil sampling and analysis reficcts vendor recommendation.
None of these changes will create new failure modes or a different type of accident.
3.
The margin of safety, as defined in the basis for any Technical Specification, is not reduced because the change will not adversely impact the design function of the EDG and any ruumed mitigating functions of any safety-related systems during accident conditions and dm. sot affect any parameters upon w hich Technical Specifications are based.
55
Fire Protection Report Channe FDRP 16-0J0 DESCRIPTION:
~his change took exception to Regulatory Guide 1.120, Quality Assurance Requirements for Fire
- Protection, as documented in Chapter 3 of the Byron /Braidwood Fire Protection Report. In particular, control of purchased material as described on Page 3.4 2, item C, of the Report. This change allowed i
purchase of carbon dioxide (CO ) under one stored item number as not safety related, as opposed to 2
regulatory related.
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q SAFETY EVALUATION
SUMMARY
1.
The probability of an occurrence, or the consequence of an accident or a malfunction of equipment important to safety as previously evaluated in the UFSAR is not increased because the quality of CO2 is expected to remain the same, and there is no change to the CO system which is still expected to be 2
_ operabic to protect safety-related, safe shutdown equipment as required.
2.
The possibility for an accident or malfunction of a different type than any previously evaluated in the UFS AR is not created because this change does r.ot affect plant operation; it only deleted the requirement for purchase order certification on each bulk shipment. The purchase order still requires National Fire Protection Association (NFPA) code-12 to be met.
a-i' 3.
The margin of safety, as defined in the basis for any Technical Specification, is not reduced because j
the change did not affect any parameters upon which Technical Specifications are based.
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$6
Fire Protection Report Channe FDRP 17-012 DESCRII' TION:.
An operability evaluation was performed to assess emergency diesel generator (EDG) operability following a turbine building fire. The fire would cause short circuits in the carbon dioxide (CO ) Panels 2
for the diesel generator (DG) rooms and isolate ventilation for both EDG rooms on either Unit 1 or Unit 2.
The evaluation concluded that sufficient time is available for manual actions to be performed to restore ventilation, and ensure continued DG operation. The Fire Protection Report was resised to include the results of the evaluation. -
i
'i S AFETY EVALUATION
SUMMARY
r 1.
The probability of an occurrence or the consequence of an accident or malfunction of equipment important to safety as previously evaluated in the UFSAR is not increased because the evaluation indicates that manual actions can be taken to restore EDG room ventilation if EDG room ventilation i
were lost due to a turbine building fire causing a spurious CO actuation.
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l 2.
The possibility for an accident or malfunction of a different type than any previously evaluated in the.
UFSAR is not created because the evaluation determines that sufficient time is available to perform manual actions to restore EDG room ventilation before EDG damage would occur, i
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' 3.
The margin of safety, as defined in the basis for any Technical Specification, is not reduced because j
the change did not affect any parameters upon which Technical Specifications are based.
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9 57
Fire Protection Report Chance FDRP 17-032 DESCRIPTION:
The Fire Protection Report was revised to indicate that there is unprotected (not fireproof) structural steel, which forms part of several fire-rated assemblies in the auxiliary building elevator equipment room walls, dumbwaiter walls, and HVAC control panel room walls, in fire zone 11.7-0.
SAFETY EVALUATION
SUMMARY
1.
The probability of an occurrence or the consequence of an accident or malfunction of equipment important to safety as previously evaluated in the UFSAR is not increased because there is no physical addition or alteration to the plant configuration as a result of this change, and no new fire hazards or ignition sources were created or introduced.
Based on the plant configuration, the existence of the unprotected steel in the fire-rated assemblics does not adversely affect the ability to achieve and maintain safe shutdown as required per Appendix R to 10 CFR 50. The " defense-in-depth" concept and its associated fire protection systems and equipment remain effective and are not adversely affected.
2.
The possibility for an accident or melfunction of a different t)pe than any previously evaluated in the UFSAR is not created because the presence of the unprotected steel does not create the potential for fire to spread between fire zones, and the level of fire protection remains unchanged.
3.
The margin of s'siety, as defined in the basis for any Technical Specification, is not reduced because this change doet not affect any parameters upon which Technical Specifications are based.
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Fire Protection ReporLChance FDRP 17-037 PESCRWTION:
The Fire Protection Report was updated to incorporate the batteries associated with the diesel-driven fire pump and Units I and 2 auxiliary feedwater pumps. The fire load associated with the batteries was not in the Fire Protection Report.
SAFETY EVALUATI.QN
SUMMARY
1.
The probability of an occurrence or the consequence of an accident or a malfunction of equipment important to safety as presiously evaluated in the UFSAR is not increased because fire hazards associated with the batteries do not exceed the capabilitics of the existing fire protection features in each room, and do not alTect equipment important to safety. The probability of a design basis fire in the affected rooms will not be measurably increased.
2.
The possibility for an accident or rnalfunction of a different type than any previously evaluated in the UFSAR is not created because the fire hazards associated with the batteries are within the protection capabilitics of the existing fire protection features in cach room. Therefore, adequate fire protection is pro ided and the existing safe shutdown analysis remains valid. This change does not adversely affect the ability to achieve and maintain safe shutdown in the event of a fire in any of the atTected arcas.
3.
The margin of safety, as defined in the basis for any Technical Specification, is not reduced because the change did not affect any parameters upon w hich Technical Specifications are based.
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59
Administrative Technical Reauirements Amendment 10 -
DESCRililON:
This amendment to the Administrative Technical Requirements resised the Radiological Effluents section to be consistent with Revision 1,3 of the Offsite Dose Calculation Manual.
SAFETY EVALUATION
SUMMARY
1.
The probability of an occurrence or the consequence of an accident or malfunction of equipment important to safety as proiously evaluated in the UFSAR is not increased because there is no impact on plant operation or equipment. The change affects routine radiological sampling only and does not affect any analyzed accident or malfunction.
2.
The possibility for an accident or malfunction of a different t3pc than any proiously evaluated in -
the UFSAR is not created because plant equipment and operation are not affected.
3.
The margin of safety, as defined in the basis for any Technical Specification, is not reduced because the chang: did not affect any parameters upon which Technical Specifications are based.
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60
Eo**-Weld Heat Treatine Heater Stuck in Steam Generator Tube Durine Slemine Proces.s DESCRIPTION:
During the Post-Weld Heat Treating (PWHT) process on the upperjoint of an ABB Combustion Enginectmg tungsten inert gas (TIG) wclded sleeve, the heater became lodged in the sleeve and was unable to be removed. The upper welded joint was complete and the lowerjoint had been hydraulically expanded. The heater was left in the sleeve and the tube was removed from senice by plugging both the hot leg and cold leg tube ends SAFETY EVALUATION
SUMMARY
t 1.
The probability of an occurrence or the consequence of an accident or malfunction of equipment important to safety as previously evaluated in the UFSAR is not increased because the tube was removed from senice by plugging both ends with an approved mechanical plug. The as-left sleeve configuration was determined through analysis to be fully capable of performing the function of a tube stabilizer in the unlikely event that the parent tube should sever due to propagation of existing flaws in the tube. The as-left heater in the sleeve / tube configuration does not affect the function of the sleeve to perform its function of a stabilizer. The weight of the heater on the tube plug is within the qualification of the plug design. The presence of the heater does not affect the function of the plug to function as the primary system boundary. The operation of the steam generator is not afTected by this configuration,
)
2.
The possibility for an accident or malfunction of a different type than any previously evaluated in I
the UFSAR is not created because system operation and performance remain unchanged. No new equipment failure modes or interactions have been created. Operation of the steam generator is not affected by the sleevc/ heater configuration. The tube had been removed from senice and is adequately stabilized. The primary pressure boundary formed by the tube plugs is maintained during all modes of operation and accident conditions, and is within the qualification and design requirements. The presence of the heater in the tubc/slecyc configuration is bounded by the plug qualification and does not affect the sleeve to act as a tube stabilizer.
3.
The margin of safety, as defined in the basis for any Technical Specification, is not reduced t cause the operation, function and integrity of the steam generator and tubes are not afTected by le presence of a heater in the plugged and stabilized tube. The steam generator plugging limit is not exceeded by the plugging of this tube and station procedure exist to ensure the plugging limit is not exceeded.
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In Situ Pressure Testing of Steam Generator Tubes DESCRIPTION:
Localized in situ pressure testing was performed on selected steam generator tubes that contained flaws at the top of the tubesheet. Individual tubes were pressurized at the top of the tubesheet with water up to 5000 pounds per square inch. The intent of the testing is to verify that the flawed satisfy the structural requirements of Regulatory Guide 1.121. The tubes were stabilized and removed from senice following the in situ pressure test.
SAFETY EVALUATION
SUMMARY
1.
The probability of an occurrence or the consequence of an accident or malfunction of equipment important to safety as previously evaluated in the UFSAR is not increased because the in situ pressure testing was performed during plant shutdown when the steam generators are drained 1
and out-of-senice. The tested tubes are monitored for burst or deformation, and contingencies were in place to repair surrounding tubes if extreme tube deformation occurred. All tubes tested were stabilized and removed from senice by tube plugging.
2.
The possibility of an accident or malfunction of a different type than any presiously evaluated in the UFSAR is not created because system operation and performance remain unchanged. No new equipment failure modes or interactions have been created. The tested tubes are stabilized and removed from senice through installation of approved tube plugs.
3.
The margin of safety, as defined in the basis for any Technical Specification, is not reduced because the tested tubes are stabilized and removed from senice through installation of approved tube plugs.
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r Steam Generator Occration With Sleeve Stabilizers Installed in in>cnice Tubes DESCRIPTIONL During the End-of-Cycle 7 Unit I steam generator cddy current inspection, it was discovered that two inservice tubes contained sleeve stabilizers at the top of tubesheet. These stabilizers were installed in the wrong tubes during the Cycle 7 mid-cycle steam generator inspection outage. The correct tubes were plugged in the Cycle 7 mid-cycle outage without the sleeve stabilizers installed. The tubes with the mis-located sleeve stabilizers were removed from senice during the End-of Cycle 7 refueling outage. A safety evaluation was performed to address steam generator operation that operated with the sleeve stabilizers installed and for the plugged tubes that are not stabilized.
SAFETY EVALUATION
SUMMARY
1.
The probability of an occurrence or the consequence of an accident or malfunction of equipment important to safety as presiously evaluated in the UFSAR is not increased. The mid-cycle eddy
)
i current results of the tubes with the mis-located stabilizers indicated no detectable degradation, therefore, no rapid corrosion mechanism occurred. The structural integrity characteristics of the sleeve stabilizer far exceed the applied fluid drag loads, therefore, the sleeve stabilizers did not represent a potential to become.: foreign object within the reactor coolant system. The unstabilized plugged tubes do not represent a potential to separate at the top of the tubcsheet prior to steam generator replacement, as determined by a flow vibration analysis. These tubes do not i
i represent a potential to interact with adjacent active tubes. Postulated tube leakage from this event would be bounded by the existing tube rupture analysis assumptions 2.
The possibility for an accident or malfunction of a difTerent type than any presiously evaluated in the UFSAR is not created because system operation and performance remain unchanged. No new equipment failure modes or interactions have been created Steam generator tube bundle integrity is expected to be maintained. The conditions of resulting from this event does not i
interact with other components of the reactor coolant system. No mechanism exists that would postulate an accident different from the current liccumg basis.
]
3.
The margin of safety, as defined in the basis for any Technical Specification, is not reduced because primary to secondary pressure boundary integrity is presided, in part, by the safety factors included in the ASME Code, and is not reduced. Safety margins would not be expected to be reduced since the potential for active tube wear is considered negligible, l
i 63 i
Steam Generator Operation with a Forcian Obiect DESCRIPTION:
During the End-of-Cycle 7 steam generator eddy current inspection, a foreign object was found on the secondary face of the IB steam generator. The object was identified as a stone grinding bit left in the steam generator from initial fabrication. The object was not able to be retrieved due to the bit head being larger than the gap between the tubes. No tube degradation was identified in adjacent tubes. As a precautionary measure, tungsten inert gas (TIG) welded sleeves that span above the top of the tubesheet were installed in all adjacent tubes.
SAFETY EVALUATION
SUMMARY
1.
The probability of an occurrence or the consequence of an accident or malfunction of equipment important to safety as presiously evaluated in the UFSAk is not increased because wear and impact evaluations conservatively demonstrate that the tubes will not experience wall degradation in excess of the plugging limit over the next cycle of operation through steam generator replacement. A postulated tube leak is bounded by the existing steam generator tube rupture analysis.
2.
The possibility for an accident or malfunction of a different type than any previously evaluated in the UFSAR is not created because system operation and performance remain unchanged. No new equipment failure modes or interactions have been created. Evaluations indicate degradation to be insignificant over the next cycle of operation. Eddy current inspections show no esidence of aggressive tube wear.
3.
The margin of safety, as defined in the basis for any Technical Specification, is not reduced because primary to secondary boundary will be maintained with the presence of the foreign object. Based on the slow or non-existent wear rate due to the object, cddy current inspections the surrounding tubes will provide suflicient lead time to enact preventatise action prior to impacting tube structural integrity.
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