ML20151Q615
| ML20151Q615 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 04/19/1988 |
| From: | Hukill H GENERAL PUBLIC UTILITIES CORP. |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| C311-88-2043, NUDOCS 8804270089 | |
| Download: ML20151Q615 (17) | |
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GPU Nuclear Corporation G a Nuclear
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s Middletown, Pennsylvania 17057 0191 717 944 7621 TELEX 84 2086 Writer's Direct Dial Number:
April 19,1988 C311-88-2043 US Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555
Dear Sir:
Three Mile Island Nuclear Station, Unit 1 (TMI-1)
Operating License No. DPR-50 Docket No. 50-289 10 CFR 50.59 Report for 1987 In accordance with the requirements of 10 CFR 50.59, enclosed are summaries of the chainges to TMI-l systems and procedures as described in the Safety Anelytis Report.
Sincerely,
. D.
ukill Vice President & Direc;cr, TMI-l HDH/SM0/her:ll48A cc: W. Russell, USNRC R. Conte, USNRC R. Hernan, USNRC Enclosure 9$
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8 ffy9 n is a subsidiary of the General Public Utilities Corporation
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1 Procedure:
1009 - TMI Unit 1 Organization Description of Change:
c The Maintenance Department was replaced by the Plant Materiel Department, and some changes were made to personnel titles and responsibilities.
Safety Evaluation Summary No previously assigned functions or responsibilities have been deleted.
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organization will continue to perform the activities previously assigned to the Maintenance Department, and in addition will be responsible for assessment of the materiel condition of the plant, and developrent and implementation of programs to maintain the materiel condition necessary for safe and reliable operation, f
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' Prceedure:
1104-2 Makeup and Purification System Operating Procedure Description of. Change:
System operation was changed from one letdown cooler nornelly in service to both letdown coolers normally operating in parallel.
Safety Evaluation Summary The change was made in order to reduce thermal stresses on the letdown coolers i
as recommended by the manufacturer and Babcock & Wilcox.
This change does not affect the assumptions upon which the accident analyses are based. Provisions were included for maintaining a balanced flow to all components, and also to allow single cooler operation if needed.
Modification:
Backup Noble Gas Monitor and Flow Indication for Condenser Vacuum Effluent (B/A 412467)
Description of Modification:
This modification provided a noble gas radiation monitor redundant to RM-A5 and flow indication f or condenser vacucm effluent. A spare TMI-2 radiation monitor was refurbished and installed as RM-A15 in TMI-1.
A flow resistance probe was recalibrated and installed in condenser effluent piping. Two rate meters and a strip chart recorder were installed in the Control Room to provide the operators with remote indication.
Safety Evaluation Summary:
The backup noble gas monitor enhances the operator's ability to detect a tube rupture in the Once Through Steam Generator.
The flow indication satisfies a requirerent of Regulatory Guide 1.97 (Category 2, type F.).
This modification did not. increase the probability of occurrence or consequences of an accident or malfunction as previously described in the Safety Analysis Report, or reduce the margin of safety as described in the Technical Specifications.
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Modification: Replacenent of Snubbers with Rigid Struts Description of Modification:
This modification replaced the following list of snubbers with rigid struts to provide the necessary seismic restraint to TMI-1 piping:
Snubber Mark No.:
CF-6 DCH-68 EF-87,88 IPE-3,4,5,6,7,8 NSE-11,37 HS-247,288 MUE-6,7,40.,41 MUH-69,321,322 SPSE-12 Safety Evaluation Summary:
The system performance of the piping is not affected by replacement of snubbers with rigid struts since as seismic restraints, they perform identically as snubbers.
Replacement of the snabbers with rigid struts does not alter thernal analysis, because only snubbers on systers with mininal thermal growth were replaced.
No plant or system operational changes have been made and original design acceptance criteria safety margins are still satisfied, therefore, no unreviewed safety question exists.
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f Modification:
Installation of Isolation Valve for WDL-T-7A/B Vents (CMR
- 0660M)
Description of Modification:
This modification added an isolation valve in the combined vent line from the Reclaimed Boric Acid Tanks (WDL-T-7A&B) to the 12" diameter Vent Header prior to the Miscellaneous Waste Storage Tank (WDL-T-2). This will allow the Reclaimed Boric Acid Tank (RBAT) suction valves WDL-V-89, 90, 91 & 92 to be repaired without a vent header outage.
Safety Evaluation Sumary:
The purpose of the modification is to allow system maintenance. The selected valve is an ITT-Grinnell diaphragm valve which is typical of valves used throughout this system.
If the valve or welds leak, they can be repaired.
The diaphragm valve cannot inadvertently fail closed and isolate RBAT's vent path to the vent header; only inadvertent manual operation of this valve is possible, and relief protection for RBAT's is assured by loop seals.
This modification will not increase the probability of occurrence or the consequences of an accident previously evaluated in the Safety Analysis Report. The modification will not increase the probability of equipment malfunctions as it is expected to improve system maintainability.
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a Modification:
Deletion of Alarm Input PS-671 A/B (CMR 0840M)
Description of Modification:
1 Main Annunciator Alarm D-3-5 "Nuc Plant H /N2 Sup Press Lo" was constantly 2
in an alarm condition because the plant operates with the hydrogen source bottles isolated and the primary hydrogen header depressurized. The hydrogen bottles are nornelly isolated to prevent hydrogen le3kage into unmonitored areas of the Auxiliary Building.
In order to make D-3-5 a meaningful alarm, 4
l this modification was initiated to delete hydrogen inputs PS-671 A/B and change the alarm window designation tn "Nuc Plant W2 Sup Press Lo".
,,a e y Evaluation Sumary:
Sft This modification provides useful eperator information by making Annunciator D-3-5 a meaningful alarm.
By operating the primary hydrogen sytter: with the hydrocen supply bottles isolated, the possibility of a hydrogen lear into unmonitored areas of the Auxiliary Building will be reduced, i
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Modification:
Extension of Fire Service Water System to the TMI-1 Operations Support Facility (8/A 412415)
Description of Modification:
This modification extends the Fire Service Water System to include the Operations Support Facility. A six-inch line and a new fire service valve (FS-Y479) were added to extend the system.
Safety Evaluation Summary:
A design calculation was performed to ensure that the Fire Service Water System is capable of supplying the Operations Support Facility (OSF) with the required flow and pressure of fire sertrice water.
Fire protection system design does not require that the OSF fire service water denand be considered concurrent with any other expected fire service water demand, therefore, the system performance requirements of the system are not affected.
Mod'fication:
125/250V.DC Station Battery "B" Replacement (B/A 412411) i Description of Modification:
This modification upgraded the 125/250V DC system by replacing the "B" station battery. The existing battery was nearing the end of its expected life due to capacity decline as a result of aging.
The replacerent battery has a greater load capacity (ampere-hours ) to accommodate present load, load growth, and capacity decline due to aging. The' load capacity has been increased from 1200 to 1500 ampere-hours.
Safety Evaluation Summary:
The new battery has a greater ampere-hour rating which will decrease the probability of failure due to age or overloading.
The DC Distribution System and its connections to the batteries have not been modified and are of sufficient size to handle the additional battery rating.
The longer recharge time necessary due to the larger battery has been determined to be acceptable.
Replacement of the battery did not increase the possibility of occurrence or consequences of an accident or malfunction, or reduce 6 safety margin.
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Modification: Letdown Reactor Building Isolation Valves Circuit Modifications (B/A 128965)
Description of Modification:
This modification modified the control circuits for MU-V2A and 28 to allow partial stroking of the valves during ESAS and RMS functional testing.
Partial stroking of the valves during testing will limit the thermal cycles to the Reactor Coolant letdown coolers.
The computer points for letdown cooler isolated were modified to indicate MU-V2A(B) greater than 10% closed. A Test Switch and 10% closed / closing indicating lights were installed on the "PCR" Panel for letdown Cooler Outlet Isolatico Valves MU-V2A and B.
Safety Evaluation Summary:
The safety functions for MU-Y2A and 28 are not altered by this modification.
During operations, the limit switch contact that stops valve travel at 10%
closed is bypassed by the Test Switch contacts. The Test Switch position is controlled by plant procedures.
During testing operations, the test signal 3
must be cleared to stop valve travel, otherwise, the valve will continue closing. With the Test Switch in its nornal position, the valves will complete their safety function.
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1 Modification: Addition of Debris Screens on Containment Isolation Valves
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(B/A 412456)
Description of Modificatio,n,:
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This modification was performed to ensure clasure of Containant Purge Isolation Valves AH-VlB and AH-V1C, which are used for Reactor Building l
purging and venting and required to maintain containment integrity, by i
preventing debris from being drawn into the valves.
Debris screens were installed in the containment purge system duct work adjacent to the 1
containment purge supply and purge exhaust isolation valves.
Safety Evaluation Summary:
This modification ensures that the performance of the Containment Purge and Vent System is not impaired due to loss of the operability of the Containment Purge Isolation Valves caused by debris which could potentially be drawn into the valves.
GPUN Letter 5211-84-2213 dated September 26, 1984 documented the commitment to install debris screens prior to the Cycle 6 startup.
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9 Modification:
Supply Header Safety Valve and Flow Indicator Installation N
(28/A 418664)
Description of Modification:
A flow meter was installed on the OTSG nitrogen supply header to monitor leakage. A safety valve was installed to provide overpressurization protection of the OTSGs during wet lay-up periods.
- Safety Evaluation Summary:
This modification is not safety-related and does not involve equipment important to safety. ' The system design basis and performance are uneffected.
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i Modification:
OTSG Auxiliary Feedwater Nozzle Thermal Sleeve Replacement (B/A 128018)
Description of Modification:
The Auxiliary Feedwater Nozzle Thernal Sleeves were replaced with an improved design utilizing a more suitable material after inspection revealed thermally induced cracks in collar-to-sleeve welds which could lead to failures.
Safety Evaluation Surnury:
The improved design of the thermal sleeve results in lower thermal stresses.
The lower thernal stresses plus the use of a more suitable material will result in improving the fatique life since the structural integrity is greatly enhanced under cycling conditions.
The following design criteria were met:
1.
The radial stiffness of the collar will be lowered to reduce the imposed thermal stresses at the sleeve to collar weld.
I 2.
The materials used in renufacturing the therrel sleeve will be changed to improve the life of the AFW nozzle.
3.
The redesigned thermal sleeve must if mit changes to existing hardware so that no modification in AFW nozzle fastening and fitting is required for the replacement of the AFW nozzle sleeves.
The replacement of the nozzle thermal sleeve with the improved design does not change the operation or the function of the Auxiliary Feedwater Systenc.
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t Modification: AH-E-15A/B Electrical Control and Damper Air Circuit Modification (B/A 123215)-
Description of Modification:
The control circuits of ventilation fans AH-E-15A and AH-E-158 were modified to eliminate the possibility of spurious control circuit signals resulting i*
from a fire in FH-FZ-1 which could cause a loss of ventilation in AB-FZ-7.
The firestat detector and the air discharge damper solenoid were disconnected. The air discharge dampers of both fans were modified so that they are held in the permanent open position.
Safety Evaluation Summary:
System performance is not affected by this modification.
Sufficient air flow is produced by the units with the air dampers in the open position.
The fans will still start and run as the result of an ES signal. Alarm functions have been maintained.
GPUN committed to perform this modification to resolve an Appendix R Modification in GPUN Letter No. 5211-87-2145 dated July 27, 1987.
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Modification:
Upgrade of EFW System to Safety-Grade Completion (B/A 412024)
Description of Modification:
Modifications have been completec' to upgrade the Emergency Feedwater (EFW)
System to safety grade system, in order to provide increased reliability in its capability to mitigate the effects of design basis accidents when the Main Feedwater System (MFW) is not available.
The following modifications incorporated the Heat Sink Protection System (HSPS) into the Emergency Feedwater System Long Term Upgrade Modification Program:
1.
Provide safety grade EFW initiation on 4 psig high containment pressure isolation signal, 2.
Provid? safety grade OTSG 1evel instrumentation and signals for MFW i
OTSG high water level isolation and 0TSG low water level initiation of the EFW System.
3.
Provide a safety grade automatic control system independent of the ICS that permits the EFW system to control OTSG 1evel.
4 Upgrade the controls for the main steam line rupture detection system to safety grade.
5.
Add cafety grade low-low level alarm and safety grade level indication in the control room for each condensate storage tank.
Safety Evaluation Summary:
This modification does not introduce any accident or malfunction not previously evaluated, nor does it increase the likelihood of occurrence or consequences of any accident as analyzed in the THI-1 FSAR.
As a result of installing redundant EFW control and block valves, providing redundant and diverse initiation / actuation signals, and utilizing a two out of four logic, the EFW system is capable of withstanding a single active component failure without loss of function, as well as prevent both spurious EFW flow to the OTSG's and MFW isolation.
Therefore, the margin of safety has not been decreased.
The upgrade of the EFW system to saft.ty-grade was completed in 1987 as documented in the NRC SER dated 2/18/87.
Portions of the modification were reported in previous 10 CFR 50.59 reports.
Final NRC action was documented in the NRC SER date 3/18/88, 1
Modification: Waste Gas H /02 On-Line Monitor (B/A 412399) 2 Description of Modification:
The purpose of this modification was to install a new eleven point on-line H /02 Analyzer System to replace the Hays System.
The Hays ten point 2
H /02 Gaseous Waste Disposal Analyzer System, which served as backup to 2the existing Beckman Analyzer System, had both operational reliability and maintenance problems.
The new analyzer system is also a Beckman System and it has the manual selection capability of continuously analyzing the H2 and 02 concentration of any one of the eleven sample streams monitored by the existing Beckman Unit.
The new Beckman unit is a complete backup for the existing Beckman Unit.
The eleven sample points to be monitored by the new unit include the ten points previously served by the Hays System.
Safety Evaluation Summary:
This modification improves the sampling capability of the system and the availability of the gas analyzers by supplying a new sanpling system for which spare parts are readily available. The sample stream selection control system is manual. With the previous Hays system, sample point sequencing was accomplished automatically with electronechancial prograrrers and solenoids.
The measurement accuracy of data produced by the Hays system (and the existing Beckman system) depended upon periodic manual recalibration of zero and span.
The new analyzers also have the capability for manual recalibration.
This change will not increase the probability of occurrence or the consequence of an accident since it adds a new manual, more reliable system but does not renove any of the capabilities that were provided by the Hays System, with exception of automatic sequencing of sample points.
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Modification: Temporary Jumper on Pressurizer Level / Heater Interlock Description of Modification:
A temporary jumper was installed to allow pressurizer heater group 1 and 2 operation with power to the level / heater interlock deenergized due to 1C ESV MCC outage. The junger was removed upon return to service of 1C ESV MCC.
Safety Evaluation Summary:
i TMI-1 was in a shutdown condition.
No safety - related systems or components were affected by the jumper being installed.
Compensatory measures for jumpering out the level / heater interlock included setting the pressurizer low l
1evel alarm at 85" to alert the operator to manually deenergize the heaters.
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