ML20093M749
| ML20093M749 | |
| Person / Time | |
|---|---|
| Site: | Fort Saint Vrain  |
| Issue date: | 01/22/1984 |
| From: | PUBLIC SERVICE CO. OF COLORADO |
| To: | |
| Shared Package | |
| ML20093M748 | List: |
| References | |
| TAC-55287, NUDOCS 8408010008 | |
| Download: ML20093M749 (22) | |
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-PUBLIC SERVICE COMPANY OF' COLORADO FORT ST. VRAIN NUCLEAR GENERATING STATION em REPORT OF CHANGES, TESTS, AND EXPERIMENTS NOT' REQUIRING PRIOR COMMISSION APPROVAL PURSUANT TO 10CFR50.59(a)
January 1,1984, through January 22, 1984 -
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r TABLE OF CONTENTS Section Title Page Introduction...................................................... 3 1.0 Public Service Company Change Notices (CN) . . . . . . . . . . . . . . . . . . 5 2.0 Public Service Company Tests (T-Tests) . . . . . . . . . . . . . . . . . . . . . . 14 3.0 General Atomic Technologies Requests fo r Te s t s ( RT-Te s t s ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 4.0 System Operating Procedures.................................. 16 5.0 Tabl e o f Abbr av i a t i o n s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 6.0 System Number Identification Table .......................... 20
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INTRODUCTION This report is submitted to comply with the requirements of-Part 50.59(b) of Title 10, Code of Federal Regulations as they-apply to Fort St. Vrain Nuclear Generating Station, Unit No. 1.
It includes the period of January 1, 1984, through January 22, 1984.
Some definitions of major terms used in this report which may be helpful:
t Change Notice - Modification work proposed and installed by Public Service Company of Colorado.
"T" Tests - Tests proposed and conducted by Public Service Company of Colorado.
"RT" Tests - Tests proposed by General Atomic Technologies and conducted by Public Service Company of Colorado.
In this report, the safety evaluation for the changes, tests, and experiments is surrmarized. The terminology used in these summaries is defined as follows:
Safety Related Items j Those plant systems, structures, equipment, and components which are identified in the FSAR, and as detailed and supplemented by applicable piping and instrument (P & I) diagrams, documents SR-6-2 and SR-6-8, to include the following:
a) Class 1 per the updated FSAR, Tables 1,4-1 and 1.4-3.
b) Safe shutdown components per the updated FSAR, Tables 1.4-2 and 1.4-3.
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_4 Safety Significant Change Changes to the facility, systems, components, or structures as described in the FSAR that may do any one of the following:
a) Affect their capability to prevent or mitigate the consequences of accidents described in the FSAR.
b) Could result in exposures to plant personnel in excess of occupational limits.
Changes in the safety related systems w'hich involve the addition, deletion, or repair of components, structures, equipment, or systems such that the original design intent is changed (i.e., changes in redundancy, performance characteristics, separation, circuitry logic, control, margins of safety, safe shutdown, accident analysis), or any change that would result in an unreviewed safety question or require a Technical Specification change.
Unreviewed Safety Question Any plant modification or aeth i ty that is deemed to involve an unreviewed safety question as defined in 10CFR50.59.
a) The probability of occurrence or the consequences ,
of an accident or malfunction of aquipment important to safety previously evaluated in the FSAR may be increased.
b) The possibility of an accident or malfunction of a different type than any evaluated previously in the FSAR may be created.
c) The margin of safety as defined in the basis for any Technical Specification is reduced.
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1.0 PUBLIC SERVICE COMPANY CHANGE NOTICES _
AllLCN's will be listed in the following order:
First - CN number.
Second - system / component numb'er.
Third - description of the-change.
Fourth - summary of safety evaluation.
CN-1255 System 92 This CN upgraded Instrument Power System 1A -and IB. The modification replaced instrument power inverters 1A and IB, added back-up power transformers to inverters IA and IB, installed additional instrument buses IA-1 and 1B-1 and a three phase static transfer switch in conjunction with Interruptible Instrument Power Bus 3. The new inverters are equipped with static transfer switches for automatic switching between preferred and alternate power systems.
The new inverters, back-up power transformers and power buses were installed in Building 10. The three phase static transfer switch was installed in the 480 Volt Switchgear Room.
Since CN-1255 provided an independent instrument power transformer to provide back-up power for each inverter which provides power to the non-Interruptible buses and an associated automatic static transfer switch, the reliability of providing electrical power to vital equipment increased. The possibility of a new accident or malfunction was not created. Increasing the reliability and flexibility of the Non-Interruptible Instrument Power System increased the system's margin of safety.
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CN-1294
~ System 92/45 This modification' performed several' changes to the 480 Volt Essential Power System. .The main project associated with CN-1294 was the electrical' connection of the three new, higher capacity 480 Volt essential switchgear. This changeout also included removing the non-essential 4160-480 Volt transformers from within the 480 Volt switchgear room which were replaced with larger units at a location outside.of the plant under CN-1605, the electrical connection of current limiting reactors on the eight (8) 480 Volt Motor Control Centers (MCCs) fed from the essential buses, and new fire detection and protection equipment for the new 4160-480 Volt transformers.
Replacement of the switchgear and transformers with new larger capacity equipment will not affect the operation of the plant electrical system with the exception of being less likely to overload the system. Moving the transformers outside will reduce heat problems previously experienced. The probability of occurrence or the consequences of a previously evaluated accident or malfunction or equipment important to safety was not increased. Since the electrical system will not function differently, there has not been any new possible accidents or malfunctions created by this modification. No specific margin of safety is defined in the Technical Specifications or FSAR concerning the capacity of the 480 Volt essential switchgear or transformers. The overall plant margin of safety will be increased by eliminating the heat load within the 3-Room Control Complex and increasing the capacity of the 480 Volt essential switchgear. The current limiting reactors which were placed on the feed to each 480 Volt MCC fed from *.he 480 Volt essential switchgear were required due to the increase in available interruptible current requirements imposed by the new switchgear.
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CN-1332 System 92 This CN upgraded Instrument Power System IC and replaced the 10
" swing" battery charger. The modificattun included replacing the IC . battery charger / inverter, installing the old 10 " swing" battery charger as a power source for the new inverter, added a back-up power transformer and an additional Instrument Power Bus IC-1. .The new inverter is equipped with a static transfer switch for automatic switching between preferred and alternate power sources.
The new inverter, old 10 " swing" battery charger, back-up power transformer and power bus were installed in Building 10. The new 10 " swing" battery charger was installed in the 480 Volt Switchgear Room.
This modification increased the capacity and reliability of the Non-Interruptible Instrument Power System IC. Battery Charger 10 was upgraded and a back-up DC source was made available to the 1C battery charger and inverter. By adding the dedicated back-up power - sources and associated automatic switching mechanisms, the possibility of a new accident or malfunction of equipment has not been created. Increasing the reliability and capacity of the instrument power system increases its margin of safety as deft.aed in the Technical Specifications. The probability of occurrence or the consequences of an accident or malfunction of equipment important to safety previously '
evaluated in the FSAR as a result of a non-interruptible power supply failure has been definitely reduced by this modification. -
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CN-1391 92/DC Power Systems This CN upgraded Station Batteries IA, IB and 1C. The modification included the "in place" replacement of batteries IA C and 18 and the replacement and relocation, to Building 10, of the IC battery.
x The replacement and relocation of battery IC which is primarily s a power source for the non-interruptible instrument bus ,'
supplying power to the Plant Protective System did not increase , ,
the probability of occurrence of any accident or malfunction /.
evaluated in the FSAR. Since the only physical change to the DC
. system was replacement of the batteries with new, increased '
capacity batteries, no possibility of a new accident or malfunction has been created. No margin of safety concerning- 4 battery capacity is defined. Since this modification is in the conservative direction by increasing the battery capacities, the modification introduced greater protection from overload and therefore less chance of a DC system failure.
CN-1462 System 70/ Building 10 This CN installed the electrical facilities of a new building (Building 10) on site.
This change is not safety significant, and as the change did not increase the probability of an accident or malfunction previously discussed in the FSAR, the change does not involve an unreviewed safety question.
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Systems 21/ Circulator Buffer Helium Auxiliaries y
)/,. ,f This modification installed a vent line in the circulator buffer helium sy' stem from the discharge of the buffer helium dryer back c '- to the PCRV.
Previcus problems existed whenever a complete loop shutdown and isolation occurred and the PCRV pressure changed compared to the buffer helium system pressure of the shutdown loop. If the buffer helium pressure was high compared to the PRCV pressure, t upon " restart" of the loop the possibility of water ingress up the circulator shafts was high. Following the installation of this modification, the Reactor Operators have the capability to reduce the ~ouffer helium pressure prior to restart of the
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The modification did not create an accident of a different type than any evaluated previously in the FSAR. The. modification also did not reduce the margin of safety as evaluated in the Safety Related Design Analysis. The overall system modification
') does not affect the limiting conditions for plant operation and
, consequer.tly does not reduce the margin of safety.
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CN-1486 System 21/73 This modification installed new piping from the Turbine Water Drain Tank (TWDT) to the Reactor Building Ventilation System.
The. installation of the vent piping from the TWDT to the reactor i building ventilation system was requested for periods when the I circulator turbine water drains have potential primary coolant contamination. This vent line would prohibit the introduction of airborne contamination to the reactor building and redirect this contamination directly to the monitored, filtered reactor building exhaust system.
The redirection of the TWDT vents to the reactor building ventilation system, only during low pressure separator bypass operations or for short intervals when there is a potential for turbine water drain contamination, prevents possible-contamination of the reactor building atmosphere. The FSAR only considers the helium circulator return lines (main drain lines) to the TWDT and the turbine water removal pumps to be items whose failure could result in interference with adequate removal of decay heat or pelton cavity drainage, therefore, this modification did not create a different accident or malfunction from those previously analyzed in the FSAR. The ability to drain the pelton wheel cavities on the circulators will not be affected regardless of which vent path is used, therefore, the margin of safety has not been altered.
CN-1605 System 92/4160-480 Volt Transformers This modification installed the new 4160-480 Volt transformers and associated support systems, such as; the outside 480 Volt bus ducts, supports, fire deluge system and other protective functions.
The changeout of the 4160-480 Volt transformers to higher capacity transformers and the relocation of these units did not change the operation of the 480 Volt essential system. The removal of the transformers from the 3-Room Control Complex significantly reduced the heat load in the 480 Volt Switchgear Room.
-The overall system reliability was increased 6:e to the more reliable transformers and by decreasing the heat levels in the 3-Room Complex. Since the specific function of the transformers was not changed and tha system reliability was increased, the possibility of a new accident or malfunction was not created.
The margin of safety had been increased pertaining to the adequacy of a source of power to the 480 Volt essential buses.
There is no specific margin of safety defined for the 4160-480 Volt transformers.
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CN-1622 Systems 92/ Essential Power Undervoltage Protective Relaying This modification removed all Class IE functions from the 4160 Volt undervoltage system and installed new protective undervoltage relays on the 480 Volt essential buses.
CN-1622 installed a. total of twelve (12) undervoltage relays on each 480 Volt essential bus. These relays, depending on the length and severity of the degraded voltage condition, will initiate a corrective action ranging from . isolation and automatic transfer of an affected bus to initiating a reactor scram. Modifications and additions to the 480 Volt protective relaying system include two-out-of-three coincidence logic on all relay logic.
As described in the FSAR, all incidents concerning a loss of offsite power (with or without a loss of the unit generator and one emergency generator) were exami.ned by the NRC and PSCo. It was determined that an occurance of loss of offsite power will initiate identical results with the new relaying modifications as with the previous undervoltage system. The probability of consequences resulting from an accident or malfunction, described in the FSAR, have not been increased. As- defined in the basis for a Technical Specification or in the FSAR, no margin of safety exists which describe the design for protective relaying for the auxiliary power system. The modification was found not to involve an unreviewed safety question.
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~CN-1629 System 92/ Current Limiting Reactors This CN physically installed the current limiting reactors on the power feed of each of the eight (8) 480 Volt Motor Control Centers (MCCs) powered by a 480 Volt essential bus.
This change was necessary due to the increased capacity of the new 480 Volt essential switchgear. The electrical connection was performed undar CN-1294, as previously discussed.
The instal ation of the current limiting reactors did not create any new accidents or malfunctions that were not previously analyzed in the FSAR. As the upgrade of the 480 Volt essential buses and subsequent installation of the current limiting reactors increased the reliability of the 480 Volt essential power system, the modification did not reduce any margin of safety, nor involve an unreviewed safety question.
CN-1703 Systems 46/63 This modification installed a vent line from the PCRV cooling water system surge tanks to the gas waste system. The change notice also analyzed the change to a nitrogen gas blanket from a hydrogen gas blanket on these surge tanks.
The modification changed the gas blanket on the 46-system surge tanks from hydrogen to nitrogen. The modification also installed a vent line from these surge tanks to the gas waste system. The vent line would be used to vent off the surge tanks whenever there is a possibility of contamination within the PCRV cooling water system.
A chemical deoxygenator will remove oxygen from the cooling water system more effectively than did the hydrogen cover gas, thus reducing the probability of corrosion of the system.
Periodic venting of the surge tanks to the gas waste systcr. ';ill not increase the probability of an accident or malfunction. Use of the chemical deoxygenctor and the nitrogen cover gas are compatible with system 46 materials and operation. The design, function and installation of the vent line was adequate to ensure safe operation. A margin of safety was increased with
.the replacement with a less reactive cover gas (nitrogen). )
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2.0 PUBLIC SERVICE COMPANY TESTS (T-TESTS)
There were no T-Tests performed during this report period.
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3.0 PUBLIC SERVICE COMPANY REQUESTS FOR TESTS (RT-TESTS)
There were no RT-Tests performed during this report period.
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" 4.0 SYSTEM OPERATING PROCEDURES r
There were no majorSystemOperatingProced'urechanges,other than those required by the modifications listed, submitted during this report period.
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5.0 TABLE OF ABBREVIATIONS ACM Alternate Cooling Method ANSI American National Standards Institute ASCO Automatic Switch Company ASTM American Society for Testing and Materials C Compressor -
CFM Cubic Feet / Minute CN Change Notice (Public Service Company)
CO 2 Carbon Dioxide CRDM Control Rod Drive Mechanism CSF Core Support Floor E Exchange (Heat)
F Filter FCN Field Change Notice (Non-Public Service Company Initiated Change)
FE Flow Element FES Final Environmental Statement FIS Flow Irdicator/ Switch FSAR Final Safety Analysis Report GAC General Atomic Company HSV Hand Solenoid Valve HV Hand ',alve
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HVAC Heating, Ventilating, and Air Conditioning.
K Engine (Diesel or Gasoline)
L Line LCV Level Control Valve N Nitrogen (Gas)
NRC Nuclear Regulatory Commission P Pump
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PCRV Prestressed Concrete Reactor Vessel PDIS Pressure Differential Indicating Switch PDT~ Pressure Differential Transmitter PDV Pressure Differential Valve PPS Plant Prctective System PS Pressure Switch PSCo Public Service Company of Colorado PSI Pounds / Square Inch PV Pressure Valve R Refueling Region (When Followed By a Number)
RERP Radiological Emergency Response Plan
, RIS Radiation Indicator / Switch RT Request for Test (General Atomic Technologies)
S&L Sargent and Lundy l
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5 SOP'- 1 System Operating Procedure-T Tank' Special Test (Public Service Company) .
- TIG Tungsten Inert Gas-I TT Temperature Transmitter
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6.0 SYSTEM NUMBER IDENTIFICATION TABLE 2' Plant Site 11- Reactor Vessel and Internal Components 12 Control Rods and Drives 13 Fuel Handling Equipment 14~ Fuel Storage- -
15 Fuel Shipping Equipment 16 Auxiliary - Equipment 17 Reflector-18 Fuel 21 Primary Coolant System (Helium Circulators and Auxiliaries) 22 Secondary Cooling System (Steam Generators) 1 23 Helium Purification System 24 Helium Storage System 25 Liquid Nitrogen System 29 Gas Charging Facility 31 Feedwater and Condensate 32 Feedwater Heater Vents and Drains l
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33 Water Treatment 41 Circulating Water System 42 Service Water System 44 Domestic Water System 45 Fire Protection System 46 Reactor Plant Cooling Water System 47 Purification Cooling Water System 48 Alternate Cooling Method 51 Turbine Generator and Auxiliaries 52 Turbine Steam 53 Extraction Steam 54 Turbine Lube Oil Purification 55 Turbine Vents and Drains 61 Decontamination System 62 Radioactive Liquid Waste System 63 Radioactive Gas Waste System 70 Structures - General 72 Reactor Building (Vents and Drains) 73 Reactor Plant Ventilation System 75 Turbine Building (Vents and Drains, HVAC) 78 Security System 79 Technical Support Building J
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83 Communication System 84- Auxiliary Boiler and Heating System 90- -Computer Systems 91 Hydraulic Power 92 Electrical Power 93 Controls and Instrumentation 98 Hydraulic Piping Snubbers '
- i 99 Miscellaneous f
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