ML20170A420
Text
Page 1 of 14 DSAR-9.7 Auxiliary Systems Component Cooling Water System Rev 5 Safety Classification: Usage Level:
Safety Information Change No.: EC 69661 Reason for Change: EC 69661 removed references to CCW Surge Tank pressure control valves.
Preparer: L. Ketcham Fort Calhoun Station
DSAR-9.7 Information Use Page 2 of 14 Component Cooling Water System Rev. 5 Table of Contents 9.7 Component Cooling Water System ................................................................................ 5 9.7.1 Design Bases ................................................................................................ 5 9.7.2 System Description ....................................................................................... 7 9.7.3 Safety Evaluation ........................................................................................ 16 9.7.4 Instrumentation ........................................................................................... 20 9.7.5 Tests and Inspections ................................................................................. 22 9.7.6 References ................................................................................................. 22
DSAR-9.7 Information Use Page 3 of 14 Component Cooling Water System Rev. 5 List of Tables Table 9.7 Component Cooling Water System, Design and Operating Data ................... 14
DSAR-9.7 Information Use Page 4 of 14 Component Cooling Water System Rev. 5 List of Figures The following figure is a controlled drawing and can be viewed and printed from the listed aperture card (i.e., file number).
Figure No. Title Aperture Card 9.7-1 Simplified Component Cooling Water Flow Diagram 67729
DSAR-9.7 Information Use Page 5 of 14 Component Cooling Water System Rev. 5 9.7 Component Cooling Water System 9.7.1 Design Bases The component cooling water (CCW) system is designed to cool components carrying radioactive or potentially radioactive fluids. It serves as a cooling medium for the spent fuel pool heat exchangers and the control room economizer coils.
The system provides a monitored intermediate barrier between these fluids and the raw water (RW) system which transfers the heat to the river. Thus, the probability of leakage of contaminated fluids into the river is greatly reduced. System components are designed to meet the maximum duty requirements during defueled operation.
Regulatory requirements, guides and other licensing basis documents that constitute generic requirements (i.e., applicable to multiple systems or topics) are covered in other sections of the DSAR. Refer to DSAR Appendix G for a listing of other Fort Calhoun Station (FCS) design criteria. FCS design criteria that are of interest relative to this DSAR section and which are specifically addressed in the associated safety evaluation are as follows:
9.7.1.1 Design Criterion 2 - Performance Standards: The CCW system is designed, fabricated, and erected to withstand without loss of capability to protect the public against additional forces that might be imposed by natural phenomena such as earthquakes, tornadoes, floods, winds, ice and other local site effects.
9.7.1.4 Design Criterion 12 - Instrumentation and Control Systems:
Instrumentation is provided for continuous measurement of all significant CCW system process variables. Controls are provided for the purpose of maintaining these variables within the limits prescribed for safe operation of the CCW system.
9.7.2 System Description The CCW system is a closed loop consisting of three motor driven circulating pumps, four component cooling (CC) heat exchangers, a surge tank, valves, piping, instrumentation and controls. The system is designed as a closed, pressurized, circuit with no venting to the building atmosphere under normal operating conditions. Heat is transferred from the CCW system to the RW system in the CC heat exchangers. The rejected heat is then discharged by the RW system to the Missouri River. The flow diagram is shown in Figure 9.7-1 and P&IDs 11405-M-10 and 11405-M-40 (Reference 9.7.6.3.1 and 9.7.6.3.2).
DSAR-9.7 Information Use Page 6 of 14 Component Cooling Water System Rev. 5 9.7.2.1 Major Components The design and operating data for the CCW system equipment are shown in Table 9.7-1.
9.7.2.1.1 Three CCW pumps (AC-3A/B/C) are installed in the auxiliary building to provide cooling water flow from the CC heat exchangers (AC-1A/B/C/D) to components.
9.7.2.1.2 Four CC heat exchangers (AC-1A/B/C/D) are installed in the auxiliary building to transfer heat from the CCW system to the RW system. The shell side of the CC heat exchangers is part of the CCW system.
9.7.2.1.3 The CCW surge tank (AC-2) accommodates system volume expansion and contraction resulting from changes in the CCW fluid temperature due to operation and load transients. Pressurization of the CCW surge tank exerts a static head on the CCW pump suction.
9.7.2.1.4 The corrosion inhibitor tank (AC-15) provides a means for addition of corrosion inhibitor chemicals to the CCW system water.
9.7.2.2 System Operation 9.7.2.2.1 Normal Operation During normal operation, one of three CCW pumps is in continuous service, while the other two are kept at standby. Pump discharge pressure, flow, and temperature are monitored in the control room. CCW temperature is maintained by adjusting the number of in service CC heat exchangers and RW pumps. The number of CC heat exchangers and RW pumps in service during normal plant operation is a function of river temperature and the amount of cooling capability needed to normally maintain CCW temperature between 55°F and 110°F (these temperatures represent the normal operating temperature range of the CCW system, not design limits).
DSAR-9.7 Information Use Page 7 of 14 Component Cooling Water System Rev. 5 If a second CCW pump is to be manually started, two CC heat exchangers must be aligned with CCW flow.
If a second RW pump is to be manually started or an automatic start is enabled, two CC heat exchangers must be aligned with RW flow. For additional CCW temperature control at low river or system temperature, a portion of CCW flow can be aligned and throttled to bypass all four CC heat exchangers through the CC heat exchangers bypass line isolation valve (HCV-497).
Flow paths can be selected from the control room by remote operation of the equipment isolation valves, and by manipulation of local manual isolation valves.
During defueled operation, the CCW system can provides cooling for the following heat loads:
Control room air conditioner economizer coils (VA-46A/B)
Spent fuel pool (SFP) heat exchanger (AC-8)
The CCW surge tank is a horizontal cylinder with a normal water level approximately at the centerline.
The upper portion of the tank contains nitrogen overpressure.
DSAR-9.7 Information Use Page 8 of 14 Component Cooling Water System Rev. 5 Nitrogen to the surge tank is normally isolated and operator action is necessary when pressure needs to be increased. A relief valves (AC-364), is provided to protect the CCW system against overpressurization and discharge to the radioactive waste disposal system.
A corrosion inhibitor is added to the CCW system at the corrosion inhibitor tank for corrosion protection.
Chemicals are placed in the tank and CCW pump recirculation is aligned to the corrosion inhibitor tank.
The chemicals are transferred to the CCW surge tank through the line connecting the two tanks and are gradually mixed into the CCW system.
The water in the CCW system is demineralized. Make up water to the CCW system is pumped to the surge tank from the demineralized water system through an automatic level control valve (LCV-2801) which is actuated by a level control switch. To satisfy safety class boundary requirements, demineralized water is normally isolated to the surge tank and operator action is necessary when level needs to be increased.
9.7.2.2.2 Abnormal Operation If the instrument air (IA) system is not restored during a LOOP, those CCW system air-operated valves not equipped with air accumulators will go to their failure positions. Loss of IA to these valves may prevent the isolation of CCW flow to non-essential components.
The emergency diesel generators (EDG) ensure power to required loads if the off site power supply is interrupted. The EDG system powers sufficient equipment to provide SFP cooling.
DSAR-9.7 Information Use Page 9 of 14 Component Cooling Water System Rev. 5 9.7.2.3 System Features 9.7.2.3.1 In the unlikely case of a CCW system failure, RW can be manually directed via normally handjacked locked closed valves to provide direct cooling of the Control Room Economizer Coils and the Shutdown Cooling Heat Exchangers for alternate Spent Fuel Pool Cooling (see DSAR Section 9.8).
A. RW backup cooling capability is not available when the RW system is out of service for maintenance. This condition is acceptable due to the short duration of the system outages, close attention to the SFP heat up rate, and the availability of makeup water sources to the SFP.
DSAR-9.7 Information Use Page 10 of 14 Component Cooling Water System Rev. 5 Table 9.7 Component Cooling Water System, Design and Operating Data Component Cooling Water Pumps, Item No's. AC-3A, AC-3B and AC-3C Number Installed 3 Type Horizontal, Centrifugal Capacity, gpm/pump 3425 Design Head, ft 210 Operating Temperature, °F Nominal 55 - 110 Design Pressure, psig 150 Design Temperature, °F 200 Materials of Construction Casing Cast Iron Impeller Bronze or Stainless Steel
- Shaft Carbon Steel
- - Use of bronze, stainless steel or cast iron is acceptable. Original impellers were cast iron; bronze and stainless steel are acceptable substitutes.
Component Cooling Heat Exchangers, Item No's. AC-1A, AC-1B, AC-1C and AC-1D Number Installed 4 Type Shell and Straight Tube Code ASME Section III, Class C,1968 and TEMA Class R Design Capacity, each, Btu/hr Nominal 12.1 x 106 Design Pressure, psig 150 Design Temperature, °F 300 Materials of Construction Shell Side Carbon Steel Tube Side Type 304 SS
DSAR-9.7 Information Use Page 11 of 14 Component Cooling Water System Rev. 5 Table 9.7 1 - Component Cooling Water System, Design and Operating Data (continued)
Component Cooling Water Surge Tank, Item No. AC-2 Number Installed 1 Type Horizontal-Cylindrical Code ASME Section VIII, 1968 Capacity, gallons 5,200 Design Pressure, psig 50 Design Temperature, °F 200 Material of Construction Carbon Steel Corrosion Inhibitor Tank, Item No. AC-15 Number Installed 1 Type Vertical-Cylindrical Code ASME Section VIII, 1968 Capacity, gallons 200 Design Pressure, psig 50 Design Temperature, °F 200 Material of Construction Carbon Steel Piping Code USAS B31.7, 1968, Class II/III and B31.1, 1967, Class NNS CL-1 Material (predominantly) Seamless, ASTM A-106
DSAR-9.7 Information Use Page 12 of 14 Component Cooling Water System Rev. 5 9.7.3 Safety Evaluation The CCW system has sufficient capacity to cool all defueled heat loads.
Analyses demonstrate that CCW flowrates to essential equipment are adequate to address system heat loads in the defueled condition.
The CCW system return temperature at the outlet of the CCW pumps is maintained at or below 160°F under operating conditions at river temperatures of 90°F or less (Reference 9.7.6.2.1). The river temperature limit of 90°F satisfies station design criteria (Reference 9.7.6.2.1) and is supported by state imposed environmental criteria (Reference 9.7.6.1.1). Heat is removed from the CCW system by the RW system.
The minimum required hydraulic performance for a CCW pump is calculated on the credited containment air cooler heat removal rate in the containment pressure analysis (Reference 9.7.6.2.1) from previous online operation.
9.7.3.1 The CCW system is designed to provide the following functions:
9.7.3.1.1 Provide a pressure boundary for the component cooling water system at raw water system interfaces.
9.7.3.1.2 Reject heat to raw water system.
9.7.3.1.3 Provide sufficient suction head for component cooling pumps AC-3A/B/C.
9.7.3.2 Design Basis Margin (References 9.7.6.2.1):
9.7.3.2.1 Each CC heat exchanger was originally designed for 2283 gpm CCW flow. The total peak heat removal rate is 400,000,000 BTU per hour with 3 heat exchangers in service (~6850 gpm total flow). The design heat removal of the CC heat exchangers bounds the current heat removal requirements in the permanently defueled condition of FCS.
9.7.4 Instrumentation 9.7.4.1 CCW system instrumentation and control functions have been provided, designed and powered in accordance with FCS Design Criteria 12 (see DSAR Appendix G) such that required CCW system functions can be controlled.
9.7.4.1.1 Alarms in the control room include CCW pump trouble alarms, CCW header and component low flow, CC heat exchanger and component high temperature alarms and CCW surge tank level and pressure alarms.
DSAR-9.7 Information Use Page 13 of 14 Component Cooling Water System Rev. 5 9.7.4.1.2 A majority of the system operational and control can be performed from the control room. The open or closed position of all remote operated valves, pressures, temperatures, flows and the operation of all pumps are monitored in the control room.
9.7.4.1.3 Flow distribution in the CCW system to the various heat loads is monitored in the control room by means of flow and/or temperature indication, and adjustments can be made by remote operation of the valves at various components as required.
9.7.4.1.4 A radiation monitor (RM-053) in the CCW pump header continuously monitors radioactivity which may have leaked into the system (see DSAR Section 11.2).
Compensatory actions are taken if the radiation monitor is removed from service.
9.7.4.1.5 Level indicating instrumentation is provided at the CCW surge tank and in the control room where high and low water level alarms are also annunciated.
9.7.5 Tests and Inspections 9.7.5.1 All the equipment in the CCW system was cleaned and tested prior to installation in accordance with the applicable codes. CCW system was also cleaned and hydrostatically tested after installation. Welds were inspected as required by the code and all other connections checked for tightness.
9.7.5.2 Prior to start-up, the CCW system was tested with regard to flow paths, flow capacity, heat transfer capability and mechanical operability. The pumps and valves were tested for actuation at the design set points. Pressure, temperature, flow and level indicating and controlling instruments were calibrated and checked for operability.
9.7.5.3 The CCW system is functionally tested periodically.
9.7.5.4 The equipment is accessible for inspection and maintenance at all times.
DSAR-9.7 Information Use Page 14 of 14 Component Cooling Water System Rev. 5 9.7.6 References 9.7.6.1 Station Design and Licensing Documents 9.7.6.1.1 NRC Letter, Final Supplement 12 to the Generic Environmental Impact Statement (GEIS) Regarding License Renewal for Fort Calhoun Station, Unit 1 (TAC No. MB3402), dated August 11, 2003 (NRC-03-0158) 9.7.6.2 Calculations and Analyses:
9.7.6.2.1 OPPD Calculation FC08496, RW/CCW System Performance Using Gothic 9.7.6.2.2 OPPD Calculation FC05693, Component Cooling Water System Design Heat Loads and Flows 9.7.6.3 Drawings 9.7.6.3.1 11405-M-10, Composite Flow Diagram Auxiliary Coolant Component Cooling System P and ID (File 41741) 9.7.6.3.2 11405-M-40, Composite Flow Diagram Auxiliary Coolant Component Cooling System Flow Diagram P and ID (File 44354) 9.7.6.3.3 DSAR Figure 9.7-1, Simplified Component Cooling Water Flow Diagram (File 67729)