ML20054F639
| ML20054F639 | |
| Person / Time | |
|---|---|
| Site: | Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png |
| Issue date: | 06/07/1982 |
| From: | Crutchfield D Office of Nuclear Reactor Regulation |
| To: | Counsil W CONNECTICUT YANKEE ATOMIC POWER CO. |
| References | |
| TASK-09-03, TASK-9-3, TASK-RR LSO5-82-06-011, LSO5-82-6-11, NUDOCS 8206170179 | |
| Download: ML20054F639 (13) | |
Text
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t LE June 07, 1982 Docket NgS gI213 LS05 Hr. W. G. Counsil Vice President Nuclear Engineering and Operations Connecticut Yankee Atomic Power Company Post Office Box 270 Hartford, Connecticut 06101
Dear Mr. Counsil:
SUBJECT:
FORWARDIfXi EVALUATION REPORT OF SEP TOPIC IX-3, STATION SERVICE AND COOLING WATER SYSTEMS FOR Tile HADDAM NECK PLANT Enclosed is a copy of our Systematic Evaluation Program Topic IX-3,
" Station Service and Cooling Water Systems", evaluation, which is based on your safety assessment of this topic.
The evaluation compares your facility, as described in Docket No.
50-213, with the criteria currently used by the regulatory staff for licensing new facilities.
He have found the design of the systems reviewed acceptable with a few exceptions. These exceptions and our recommendations are as follows:
Cocoonent Cooling Water System The need for system rodification to eliminate potential passive single Ny failures will be evaluated during the integrated assessment.
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Service Water System psu The 1icensee should verify that those motor-operated valves relied on A DD'-
for system isolation in the event of a loss of offsite AC power receive s.32n d emergency power, have a fail closed design, or that sufficient time is available for operator action to close the valves.
The licensee should demonstrate by test or analysis that adequate proce-dures exist to balance system flow requirements and maintain system components below design thermal limits for a single active failure.
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I h The licensee should demonstrate the ability to provide power to a second SWS pump with one pump out of service.
(Assuming that the active failure was a diesel generator.)
The licensee should demonstrate that single passive failures (pipe break in containment fan cooler supply header) would not compromise containment integrity or core cooling in the event of a LOCA.
This evaluation will be a basic input to the integrated safety assessment for your facility. This topic assessment may be revised in the future if your facility design is changed or if NRC criteria relating to this topic are modified before the integrated assessment is completed.
Sincerely, Dennis !i. Crutchfield, Chief Operating Reactors Branch No. 5 Division of Licensing
Enclosure:
Draft SEP Topic IX-3 cc w/ enclosure:
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s Mr. W. G. Counsil cc Day, Berry & Howard Counselors at Law One Constitution Plaza Hartford, Connecticut 06103 Superintendent
. Haddam Neck Plant RFD #1-Post Office Box 127E East Hampton, Connecticut 06424
. Mr. Richard R. Laudenat Manager, Generation Facilities Licensing Northeast Utilities Service Company P. O. Box 270 Hartford, Connecticut 06101 Board of Selectmen Town Hall Haddam, Connecticut 06103 State of Connecticut 0Ffice of Policy and Management ATTN:
Under Secretary Energy Division 80 Washington Street Hartford, Connecticut 06115
~U. S. Environmental Protection Agency Region I Office ATTN:
Regional Radiation Representative JFK Federal Building Boston, Massachusetts 02203
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Resident Inspector Haddam Neck Nuclear Pcwer Station c/o'U. S..NRC East Haddam Post Office East Haddam, Connecticut 06423 Ronald C. Haynes, Regional Administrator Nuclear Regulatory Commission, Region I 631 Park Avenue King of Prussia, Pennsylvania 19406
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e SEP REVIEW 0F STATI0ti SERVICE At4D COOLING WATER SYSTEMS TOPIC IX-3 FOR THE HADDAM tiECK PLAfiT e
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I.
INTRODUCTION The safety objective of Topic IX-3 is to assure that the cooling water systems have the capability, with adequate margin, to meet design objectives and, in particular, to assure that:
1.
Systems are provided with adequate physical separation such that there are no adverse interactions among those systems under any mode of operation; 2.
Sufficient cooling water inventory has been provided or that adequate provisions for makeup are available; 3.
Tank overflow cannot be released to the environment without monitor-ing and unless the level of radioactivity is within acceptable limits; and 4.
Vital equipment necessary for achieving a controlled and safe shutdown is not flooded due to the failure of the main condenser circulating water system.
1 II.
REVIEW CRITERIA The current criteria and guidelines used to determine if the plant systems meet the topic safety objective a those provided in Standard Review Plan (SRP) Sections 9.2.1, " Station Service Water System," and 9.2.2., " Reactor Auxiliary Cooling Water Systems."
In determining if plant design confirms to a safety objective, use is made, where possible, of applicable portions of' previous staff reviews.
For example, safety objective 4, identified
- above, is being reviewed as a part of SEP Top.ic III-5.B, " Pipe Breaks Outside Containment." Therefore, it is not addressed in this topic.
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III.
RELATED SAFETY TOPICS AND INTERFACES The scope of review for this topic was limited to avoid duplication of effort since some aspects of the review were performed under related topics.
The related topics and the subject matter are identified below.
Each of the related topic reports contains the acceptance criteria and review guidance for its subject matter.
II-2.A Severe Weather Phenomena II-3.B.1 Flooding of Equipment III-3.8 Flooding of Equipment (Failure of Underdrain System)
VI-7.D Flooding of Equipment (Long Term Passive Failures)
III-3.C Inservice Inspection of Water Control Structures III-4.C Internally Generated Missiles III-5 Mass and Energy Releases (High Energy Line Break)
VI-2.D Mass and Energy Releases III-6 Seismic Qualification VI-7.C.1 Independence of Onsite Power VII-3 Systems Required for Safe Shutdown VIII-2 Diesel Generators IX-1 Fuel Storage IX-6 Fire Protection VI-10.B Shared Systems for Multiple Unit Stations
The following topics are dependent on the present topic information for completion:
VI-3 Containment Pressure and Heat Removal Capability IX-5 Ventilation Systems IV.
REVIEW GUIDELINES In addition to the guidelines of SRP Sections 9.2.1 and 9.2.2, in determining which systems to evaluate under this topic the staff used the definition of " systems important to safety" provided in Reference 1.
The definition states systems important to safety are those necessary to ensure (1) the integrity of the reactor coolant pressure boundary, (2) the capability to shutdown the reactor and maintain it in a safe condition, or (3) the capability to prevent, or mitigate the consequences of, accidents that could result in potential offsite exposures comparable to the guidelines of 10 CFR Part 100, " Reactor Site Criteria." This definition was used to determine which systems or portions of systems were " essential."
Systems or portions of systems which perform functions important to safety were considered to be essential.
It should be noted that this topic will be updated if future SEP reviews identify additional cooling water s,ystems that are important to safety.
'V.
EVALUATION The systems reviewed under this topic are the component cooling water system, the service water system and the clos ~ed cooling water system'.
A.
dbmponent Cooling Water System The component cooling system is an intermediate cooling system provided to transfer heat from the components containing reactor coolant to the service water cooling system.
The maximum component cooling heat load occurs during the initial stages of residual heat removal system operation during reactor plant cooldown.
The component cooling system (and residual heat removal system) is designed to reduce the temperature of the reactor coolant system to 104 F within approximately 20 hours2.314815e-4 days <br />0.00556 hours <br />3.306878e-5 weeks <br />7.61e-6 months <br /> after reactor shutdown when the river water temperature is 80 F.
During operation, component cooling water is pumped through the shell side of the component cooling heat exchangers, where it is cooled by river water, and then flows in parallel circuits to cool the following components:
Reactor coolant pump thermal batteries and bearing oil coolers Neutron shield tank cooler Drain cooler Nonregenerative heat exchanger Seal water heat exchanger Sample heat exchangers Residual heat exchangers Charging pump oil coolers Residual heat removal pump seal coolers Baron recovery system equipment Containment penetration coolers
The specific equipment and/or systems to which the CCW system supplies cooling which are considered safety-related are the Reactor Coolant Pump Thermal Barriers, Nonregenerative Heat Exchanger, Seal Water Heat Exchanger, RHR Heat Exchangers, Charging Pump 011 Coolers, and Residual Heat Removal Pump Seal Coolers.
Pressure detection equipment is provided on the component cooling pump discharge header which automatically starts one of the standby pumps if the header pressure fails below the normal discharge pressure by a predetermined amount.
An alarm in the control room would, indicate this abnornal condition.
The component cooling surge tank accomodates expansion, contraction, and a small in-leakage of reactor coolant water, should one occur.
It also ensures a continuous component cooling water supply until isola-tion of a leaky cooling line can be accomplished.
The surge tank is normally vented to atmosphere through the air filter and ventilation and pump fans.
A radiation monitoring channel is located in the component cooling pump inlet header.
This annunciates in the main control room and closes a valve in the surge tank vent line, if the radiation level reaches a preset level above normal background. The component cooling surge tank is located at an elevation which provides the required net positive suction heat (NPSH) for proper operation of the component cooling pumps.
During normal full-power operation, one component cooling pump-and one component cooling heat exchanger accomodates the heat removal loads.
g Any one of the three pumps and a standby heat exchanger provides 100 percent backup during normal operation.
Operation of three pumps and botn heat exchangers is intended duri'ng the removal of residual and sensible heat during plant cooldown.
Failure of a single component may extend the time-to-cooldown, but should not affect the safe opera-tion of the plant.
Based on our review of the component cooling water system, we have determined that sufficient redundancy and emergency power capability for the individual components of the component cooling water system is provided.
Although the pumps and heat exchangers of the component cooling water system are redundant, they are connected to single-pipe headers for supply and return whose failure could disable the system.
This passive failure issue will be evaluated during the integrated assessment.
The capability of the plant to withstand the effects-of postulated flooding from pipe leaks are addressed in SEP Topic III-5.B. " Pipe Breaks Outside Containment."
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B.
Service Water System The service water system provides a supply of cooling water to both the primary and secondary plants.
It also provides the water required for cleaning the traveling water screens and the motive force,for injecting hypochlorite into the circulating water system.
Equipment Supplied Cooling by Service Water System Bearing Gland Water Supply to Circulating Water Pumps Emergency Diesel Generators
- Kydrogen Seal Oil Coolers Closed Cooling System Heat Exchangers Main Exciter Coolers Turbine Oil Coolers Isolated Phase Bus Coolers Generator Hydrogen Coolers Chem Lab A/C Unit Office Building A/C Unit Control Room A/C Unit
- Spent-Fuel Pool Heat Exchangers*
Primary Drain Tank Vent Condensers Reactor Containment Recirculation Air Cooling Coils
- Reactor Containment Ventilation Fan Motor Coolers
- Main Steam Sample Cooler Motor-Driven Auxiliary Feedwater Pump Waste Evaporator Overhead Condenser Distillate Cooler i
Component Cooling Heat Exchangers*
Residual Heat Removal Heat Exchangers*
Sample Pump Steam Generator Blowdown Tank Condensers Evaporator Overhead Condenser Denotes safety-related load Four 2-stage, vertical centrifugal pumps are provided to supply all the service water system requirements.
Each pump is rated at 6,000 gpm and 150 feet TDH when operating at 1,185 rpm.
The pump intake columns are submerged in the pump well of the screen well house.
Shaft sealing is accomplished with one standard packed stuffing box, and pump bearings are lubricated by the pumped liquid.
Each pump is driven through a solid coupling by a 250 hp vertical, solid shaft, induction motor having an open drip-proof. enclosure.
The service water pumps are normally started and stopped by manual controls on the main control board.
With a maximum river water design temperature at 85*F, three of the four pumps are required to supply the station cooling demands during normal plant operation.
Any combination of nonoperating pumps can be selected for standby duty.
All pumps on standby duty will start automatically whenever a pressure drop occurs in the service water header.
Running pumps, whether started manually or automatically, will keep running until
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stopped from the main control room.
Power for all the service water pumps is included in the capacity of the emergency diesel generators.
Upon the loss of all normal alternating current power and after the emergency power supply is established, one service water pump will be started automatically on each diesel generator.
If the first service water pump does not start, the power supply is automatically transferred to the second pump on that diesel generator bus.
The service water system is a dual-header system in which two parallel full-size headers supply both the primary and secondary plants.
In the turbine building, each header divides into a primary plant supply header and a secondary plant header.
Each service water supply branch connection to a piece of equipment or a group of equipment in both the primary and secondary plants is connected to both headers and valves -to permit shutoff from -
either or both headers.
1 hranch supply lines from the primary plant service water supply header penetrate the reactor.containnent for cooling water supply to the reactor containment air recirculation cooling coils and to the reactor coolant pump bearing coolers.
Service water hose connections are also provided inside the reactor containment.
Wherever feasible, provisions have been made for convenient access to the tube sides of heat exchangers in the service water system for the cleaning and flushing of tubes.
In some cases, special curb and drain arrangements are provided to carry the flushing water to the floor drain system.
Where it is considered not feasible to open the heat exchangers for flushing, filters are provided in the service water supply lines to preclude the necessity for tube cleaning.
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. Motor-operated valves at the beginning of the secondary plant header automatically close to isolate the secondary plant service water supply in the event all offsite power is lost. Air-operated isola-tion valves are provided to the Spent-Fuel Pool Cooling Heat Exchangers, boron recovery overhead condenser, waste evaporator, and blowdown con-densers to isolate the service water supply to these components in the event of loss of all offsite AC power.
In addition, the air-operated valves to these components fail to close in the event of loss of instrument air.
Two motor-operated isolation valves on the service water outlet of the component cooling water heat exchanger also automatically close upon loss of offsite AC. Also, air-operated flow-control valves on the outlet piping of the emergency diesel generator coolers, which are suppled air from the diesel generator air starter cylinders, also fail open to ensure service water is supplied to the diesel generators under all required operating conditions.
Automatic isolation of the previously-discussed components was included in the plant design to ensure sufficient service water was available to supply the CAR Fans, Emergency Diesel Generators, and RHR Heat Exchangers following a loss of offsite power coincident with the design basis LOCA.
The licensee should verify that those motor-operated valves relied on for system isolation in the event of loss of all of'5ite AC power receive emergency power or have a fa-il closed design.
g As stated previously, the flow requirements under normal operating conditions are suppled by any combination of three service water pumps.
In addition, as was previously stated, upon loss of offsite AC power, one service water pump will be started automatically on each diesel generator. A failure of one diesel generator in the post-accident. condition will result in only one service water pump being available in the short term.
This is the most limiting configuration i
for the service water system since one pump must supply the post-j accident service water cooling loads.
The post-accident heat loads that are required immediately are the Containment Air Coolers, Com-ponent Cocling Water System Heat Exchangers (it should be'noted that l
subsequent discussions will address the plant design of automatic l
isolation of service water to the component cooling water heat ex-changer) and the emergency diesel generators.
The Control Room Air Conditioning Unit will not be discussed, as a result of the entire i
Control Room Ventilation System being reviewed under Item III.D.3.4 of TMI Action Plan HUREG-0737, " Control Room Habitability." Any l
required modification will be addressed under that TMI issue.
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The service water system is susceptible to the single failure of the valves which isolate the noncritical header in the event of a LOCA coincident with a loss of offsite power.
In the _ event of a failure of these valves to close, the SWS flow will be directed to noncritical as well as critical components.
Thus, for the limiting case of one service pump operating, sufficient service water will not be provided to the various critical components previously discussed.
- However, the isolation valve for the noncritical header can be manually closed to increase the flow to the critical components.
The licensee should demonstrate that adequate procedures exist to balance system flow requirements and to maintain system components below design thermal limits.
The licensee performed an evaluat1 n of potential passive failures.
9 Tha only case identified in which a potential failure could disable an essential component is the service) water supplies to the containment air coolers.
In the event a pipe rupture of the service supply header to containment air cooler were to occur downstream of the header isolation valves, service water flow to the containment air cooler could. be eliminated.
However, the containment spray system provides redundant containment coolino capability to the containment air coolers.
In addition, the licensee indicated that since the SWS is a moderate enerQY Dipinq system, a pipe failure Would probably result in a leak rather than complete rupture.
The leakage rate calculated in accordance with Branch Technical Position MEB 3-1 appended to Standard Review Plan 3.6.2 is estimated 0 (800 gal / min) from the 24" piping using a SWS pressure of 65 psig. Although a leak of (800 gal / min)
\\ may pose a flooding problem, the SWS function would not be significantly impaired with a minimum of two service water pumps in operation.
Since the present technical specifications do not restrict plant operation with one inoperative SWS pump, the licensee should demonstrate that power could be provided to a second SWS pump.
(Assuming that the active failure was a diesel generator.) The capability of the plant to withstand the effects of postulated flooding from pipe leaks are addressed in SEP Topic III-5.B. " Pipe Breaks Outside Containment."
C.
Closed Cooling Water System The closed cooling water system consists of the closed cooling water pumps (2), closed cooling water heat exchangers (2), surge tank, hydro-pneumatic storage tank, and associated valving and controls'.
Cooling water is provided to the CCW HX by the service water system.
. The closed cooling water system provides cooling for the following components:
Vacuum Deaerator Pumps Steam Quality Analyzer Feedwater Sample Cooler Hydrogen Analyzer -
Dew Point Hygrometers Steam Generator Feed Pump 011 Coolers Control Air Compressors and After Cooler Service Air Compressors and After Cooler Stuffing Box Cooling Jacket Based on our review of the closed cooling water system we have determined that this system is not important to safety as defined in Reference 1.
VI.
CONCLUSIONS Based on our review of the service and cooling water systems, we have concluded that the essential systems and functions are:
Component Cooling Water System:
Reactor Coolant Pump Thermal Barriers, Nonregenerative Heat Exchanger, Seal Water Heat Ex-changer, Residual Heat Exchanger. Charging Pump 011 Coolers, and Residual Heat Removal Pump Seal Coolers -
Se6vice Water System:
Diesel Generator Control Room A/C Unit, Spent-Fuel Pool Heat Exchangers, Reactor Containment Recircula-tion Air Cooling Coils, Reactor Containment Ventilation Fan Motor Coolers, Component Cooling Heat Exchangers, and Residual Heat Removal Heat Exchangers l
We have found the design of these systems meet the requirements of GDC l
44, 45 and 46 with the following exceptions:
A.
Component Cooling Water System Yhe need for system modification to eliminate potential passive single failures will be evaluated during the integrated assessment.
B.
Service Water System The licensee should verify that those motor-operated' valves relied -
on for system isolation in the event of a loss of offsite AC power receive emergency power, have a fail closed design, or that sufficient l
time is available for operator action to close the valves.
The licensee should demonstrate by test or analysis that adequate procedures exist to balance system flow requirements and maintain system components below design thermal limits for a single active failure.
The licensee should demonstrate the ability to provide power to a second SWS pump with one pump out of service.
(Assuming that the active failure was a diesel generator. )
The licensee should demonstrate that single passive failures (pipe break in containment fan cooler supply header) would not compromise containment integrity or core cooling in the event of a LOCA.
VII.
REFERENCES Regulatory Guide 1.105, hystems Setpoint,s.
1.
2.
Haddam Neck FDSA 2.
Standard Review Plan Sections 9.2.1, 9.2.2.
3.
Standard Review Plan Sections 9. 2.1, 9. 2. 2.
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4.
Licensee's Topic IX-3, Safety Assessment Report, submitted by letter dated December 14, 1981.
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