ML20236W053
ML20236W053 | |
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Site: | 05000470 |
Issue date: | 09/11/1987 |
From: | ABB COMBUSTION ENGINEERING NUCLEAR FUEL (FORMERLY |
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EFFECTIVE PAGE LISTING CHAPTER 10 Table of Contents Paae Amendment i 12 11 12 iii 12 Text I Paae Amendment i 10.1-1 through 10.4-4 12 10.4-5 ,
10.4-6 through 10.4-20 12 T@les Amendment 10.1-1 12 10.3.5-1 12 10.3.5-2 12 Fiqures Amendment 10.1-1 12 10.1-2 12 10.1-3 10 10.3.2-1 12 10.4.7-1 12 10.4.7-2 12 10.4.7-3 12 10.4.8-1 . 12 8712070240 871130 PDR ADOCK 0500 0 Amendment No. 12 B
September 11, 1987
l TABLE OF CONTENTS Section Subiect Pace No.
10.0 STEAM AND POWER CONVERSION SYSTEM
- 10.1-1 10.1
SUMMARY
DESCRIPTION 10.1-1 10.2 TURBINE GENERATOR 10.2-1 10.3 MAIN STEAM SUPPLY SYSTEM 10.3-1 10.3.1 DESIGN BASES 10.3-1 10.3.2 SYSTEM DESCRIPTION 10.3-2 10.3.3 SAFETY EVALUATION 10.3-11 10.3.4 INSPECTION AND TESTING REQUIREMENTS 10.3-12 10.3.5 SECONDARY WATER CNEMISTRY 10.3-12 10.3.6 STEAM AND FEEDWATER SYSTEM MATERIALS 10.3-15 10.4 OTHER FEATURES OF STEAM AND POWER CONVERSION SYSTEM 10.4-1 12 10.4.1 MAIN CONDENSER 10.4-1 10.4.2 MAIN VACUUM SYSTEM 10.4-4 10.4.3 TURBINE GLAND SEALING SYSTEM 10.4-4 10.4.4 TURBINE BYPASS SYSTEM 10.4-5 10.4.5 CIRCULATING WATER SYSTEM 10.4-8 10.4.6 CONDENSATE CLEANUP SYSTEM 10.4-8 10.4.7 CONDENSATE AND FEEDWATER SYSTEMS 10.4-9 10.4.8 STEAM GENERATOR BLOWDOWN SYSTEM 10.4-16 10.4.9 EMERGENCY FEEDWATER SYSTEM 10.4-20
- Chapter 10 will be updated in future submittals to include baseline data from Chapters 6 and 15 safety analyses and the System 80+ probabilistic risk as sessnent.
Amendment No. 12 i September 11, 1987
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I
' TABLES l
10.1-1 Steam and Power Conversion System Design and Performance Characteristics (LATER)-
10.3.5-1 Operating Chemistry Limits for Secondary 12 Steam Generator Water 10.3.5-2 ' Operating Chemistry Limits for Feedwater and Condensate T
Amendment No. 12 ii September 11, 1987 m._ ._ _ _ _ _ _ _ _ _ _ . .__s
FIGURES 10.1-1 Flow Diagram of Steam and Power Conversion System 12 10.1-2 Heat Balance for Steam and Power Conversion System (LATER)
Main Steam System Piping and Instrumentation Diagram 10 10.1-3 10.3.2-1 Atmospheric Dump Valve Flow Requirements l
10.4.7-1 Steam Flow Versus Power 1
10.4.7-2 Steam Generator Jutlet Pressure Versus Power 12 10.4.7-3 Economizer /Downtomer Flow Split 10.4.8-1 Flow Diagram of Steam Generator Blowdown System j i
Amendment No. 12 iii September 11, 1987
y e L
J 4 10.0 STEAM AND POWER CONVERSION SYSTEM 10.1
SUMMARY
DESCRIPTION 1
'The function of the Steam.and Power Conversion System is to convert the heat energy generated by the nuclear reactor into electrical energy. The heat energy produces steam in two steam generators capable of driving a turbine
. generator unit.
The Steam and Power Conversion Syster utilizes a condensing cycle with -
regenerative . feedwater heating. Turbine exhaust steam is condensed in a conventional surface type condenser. The condensate from the steam is returned to the steam generators through the condensate feedwater system.
A Turbine Bypass System capable of relieving 55 percent of full load main steam flow is provided to dissipate heat from the Reactor Coolant System during turbine and/or -reactor trip. This system consists of eight turbine bypass . valves ' to limit pressure rise in the steam generators following cessation of flow to the turbine. Once the steam flow path to the turbine has been blocked' by the closing of the turbine valves, decay heat is removed by directing steam to the condenser.
In addition-to the above, atmospheric steam dump valves are connected to the main steam lines upstream of the main steam line isolation valves to provide the' capability to hold the plant at hot standby or, in the event of loss of power to the condenser circulating. water pumps, cool the plant down to the 12 point at which the shutdown cooling system may be utilized. These valves are not part of the Turbine Bypass System; no credit for their use is assumed in obtaining the 55 percent capacity of the Turbine Bypass System.
Overpressure protection for the shell side of the steam generators and the
. main steam line piping up to the inlet of the turbine stop valve is provided by spring-loaded safety valves. Modulation of the turbine bypass valves discussed earlier would normally prevent the safety valves from opening. The steam bypass system, coupled with the reactor power . cutback system, would prevent opening of the safety valves following,a turbine and/or reactor trip.
Each steam generator has two steam discharge lines. Each line is provided with a flow measuring device, five spring-loaded safety relief valves, a main steam isolation valve, and a power operated atmospheric dump valve.
Additionally .one of the two lines utilizes a bypass line.and valve around the respective main steam isolation valve. Each main steam line is provided with l a turbine stop valve and a control valve just upstream of the high pressure j
' turbine. '
Two turbine and two electric driven emergency feedwater pumps are provided to assure that adequate feedwater will be supplied to the steam generators in the event of loss of the main and startup feedwater pumps. The Emergency Feedwater System is discussed in Subsection 10.4.9.
The safety related portions of the Steam and Power Conversion System are as follows:
Amendment No. 12 10.1-1 September 11, 1987
- a. Emergency Feedwater System, including main feedwater isolation valves and piping to steam generators.
- b. Main steam isolation valves, including piping from steam generators.
- c. Atmospheric dump valves.
- e. Steam supply to Emergency Feedwater System.
- f. Feedwater main isolation valves including piping from steam j generators. l Means are provided to monitor and prevent the discharge of radioactive material to the environment to insure that technical specifications are met under normal operating conditions or in the event of anticipated system malfunctions or fault conditions.
Figures 10.1-1,10.1-2 and 10.1-3* provide an overall system flow diagram and heat balance. See the site specific SAR for additional detailed information.
12
- Figures 10.1-1 and 10.1-2 provide a preliminary design concept and may be revised as part of the final system design. More detailed information will be provided on system connections and instrumentation when Chapters 7, 8 and 18 are submitted.
Amendment No. 12 10.1-2 September 11, 1987
l' ,
TABLE 10.1-1 STEAM AND POWER CONVERSION SYSTEM. DESIGN AND PERFORMANCE CHARACTERISTICS (LATER) 12 l
Amendment No. 12 September 11, 1937 l
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I 10.2 TURBINE GENERATOR (Later - pending completion of EPRI Chapter 13) 12 1
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Amendment No. 12 10.2-1 September 11, 1987 i
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I i-10.3 MAIN STEAM SUPPLY-SYSTEM l
10.3'.1 DESIGN-BASES
- 1. The Main Steam Supply System is designed to:
a) Deliver steam from the secondary side of the NSSS steam generators to the turbine generator.
b) Dissipate heat during the initial phase of plant cooldown.
c) Dissipate heat from the RCS following a turbine and/or reactor trip.
d) Dissipate heat when the main condenser is not available.
e) Provide steam for:
- 1. Main feedwater pump turbines
- 2. ' Emergency feedwater pump turbines
- 3. Condenser steam air ejectors
- 4. Turbine gland seals
- 5. Miscellaneous auxiliary equipment 12
- 6. Feedwater heaters 7.. Steam reheaters f) Isolate the NSSS steam generators from the remainder of the main steam system when necessary (including containment isolation, post LOCA).
g) Provide adequate overpressure protection for the NSSS steam generators and main steam system.
h)' Conform to applic'able design codes.
- 1) Permit visual inservice inspection.
j) Adequately cover the environmental operating conditions for the system and be thermally insulated to protect personnel, adjacent equipment, and conserve energy.
- 2. The safety related portion of the main steam system is that portion between the steam generators down to and including the main steam isolation valves.
Amendment No. 12 10.3-1 September 11, 1987
i!
10.3.2 SYSTEM DESCRIPTION Steam is generated in two steam generators by heat transferred from the Reactor Coolant System to the feedwater. Steam for the turbine driven emergency feedwater pumps is taken from either of the two steam generators via two of the four main steam lines at a point outside of containment and upstream of the main steam isolation valves (MSIVs).
High pressure steam from the high pressure turbine is used to heat the feedwater in the high pressure feedwater heaters. Lower pressure steam from the low pressure turbines is used to heat the feedwater in the low pressure feedwater heaters. I Five ASME Code spring loaded secondary safety valves are provided for each individual main steam line for protection against over pressurization of the shell side of the steam generators and the main steam line piping up to the inlet of the turbine stop valve.
An atmospheric steam dump valve is provided on each main steam line downstream of the safety valves and upstream of the MSIVs.
Each main steam line is provided with an isolation valve for positive isolation against forward steam flow and isolation against reverse flow. The MSIV on one of the two lines from each steam generator is provided with a bypass around it for warm-up of the steam lines downstream of the isolation valves and pressure equalization prior to admitting steam to the turbine.
Downstream of the MSIVs are eight power-operated bypass valves to bypass steam to the condenser. These valves comprise the Turbine Bypass System, which is 12 discussed in Subsection 10.4.4. Each of the four main steam lines is provided with a turbine stop valve and a turbine control valve to shutdown and control the turbine.
The following standardized functional descriptions and requirements present the system configuration necessary to meet the Nuclear Power Module (NPM) licensing, safety, and reliability requirements. The final detailed design and layout of the main steam supply system are described in the site-specific SAR.
10.3.2.1 System Performance
- 1) The main steam piping, its isolation valves, all steam branches, their isolation valves, and all associated supports from the steam generators up to and including the required isolation valves are Seismic Category I, and are designed in accordance with the requirements of Section III of the ASME Boiler and Pressure Vessel Code, Class 2. The remaining steam piping is in accordance with ANSI-831.1. The steam piping and supports are designed so that any single adverse event, such as a ruptured main steam line or a closed isolation valve, can occur without:
- a. Initiating a loss-of-coolant incident;
- b. Causing failure of any steam lines, Main Steam Isolation Valves (MSIV), Main Feed Isolation Valvec (M71V), Safety Valves, Atmospheric Dump Valves, or any feedwater line required for controlled cooldown of the unaffected steam generator; Amendment No. 12 10.3-2 September 11, 1987
- c. Preventing the Reactor Protective System and Engineered Safety Features Actuation systems from initiating proper safety actions;
'd. Transmitting excessive loads to the containment pressure boundary;
- e. Compromising the function of the plant control room; or, ,
.f. Precluding an orderly cooldown of the RCS.
- 2) The design pressure, temperature and flow rating of the main steam piping and valves are greater than or equal to the design pressure, temperature and flow rating of the steam generator secondary side.
10.3.2.2 System Arrangement
- 1) All valves in the main steam lines outside of containment up to and including the MSIVs are located as close to the containment wall as practical.
- 2) The ' main steam lines are headered together prior to the Turbine Stop Valves but not upstream of the MSIVs, and a cross-connect line is arranged such that the pressure drops between each steam nozzle and the main steam cross-connect line are approximately equal. Specifically, the difference between steam line pressure drops shall be within: 12 l
- 1. 1 psi for 0-15% power operation;
- 2. 3 psi for 15%-100% power operation; and,
- 3. less than- 30 psi for transient conditions of no greater than 1 minute duration.
The cross-connection is sized to allow full closure, at 90% power, of one of the HP turbine stop valves without imposing a severe pressure / load transient on one of the steam generators.
- 3) There are no isolation valves in the main steam lines between the steam generators and the Secondary Safety Valves. The steam line. AP between the steam generator and the safety valves is minimized.
- 4) The MSIVs, the Secondary Safety Valves, the Atmospheric Dump Valves, and the MSIV Bypass Valves are protected against tt'e effects of missiles, steam, pipe whip, etc., such that'these events cannot prevent the valves from performing their required safety function.
- 5) The Secondary Safety valves are installed in accordance with the applicable provisions of the ASME Boiler and Pressure Vessel Code Section III-Division 1, Nuclear Power Plant Components (Subsection NC-Class 2 Components).
- 6) The Secondary Safety Valve discharge piping is arr anged and supported such that the limiting loads are not exceeded for normal and relieving conditions.
Amendment No. 12 10.3-3 September 11, 1987
- 7) In the combined event of a steam line break and the loss of power or a steam generator tube rupture and loss of power, personnel access to the .
manual operator of the intact Atmospheric Oump Valves on the intact steam ;
generator is possible.
- 8) Each automatica'ily actuated valve, located upstream of the Main Steam Isolation Valves, will close on a main steam isolation actuation signal except as required for the steam driven emergegy feedwater pumps. The maximum allowable flow rate per line is 1.9 x 10 lbm/hr. '
i
- 9) The system piping is designed to allow cleaning for the removal of f foreign material and rust prior to operation and to prevent introduction 4 of this material into the turbine. Chemical cleaning or hand cleaning may be employed. During chemical cleaning, no fluid can enter the steam generators. Suitable bypass piping is provided where applicable.
- 10) Emergency feedwater pump turbine steam supplies are taken off the main steam lines upstream of the Main Steam Isolation Valves.
- 11) Main feedwater pump turbine steam supplies are located on the downstream side of the Main Steam Isolation Valves. ,
- 12) Following a secondary line break, either all steam paths downstream of the MSIVs are shown to be isolated by their respective control systems '
following an MSIV Actuation Signal, or the results of a blowdown through a non-isolated path are shown to be acceptable. An acceptable maximum steam flow from a non-isolated steam path is 10% of Maximum Steaming 12 Rate *. It is not required that the control systems for downstream valves nor the downstream valves themselves be designed to ASME Code,Section III, Seismic Category I, IEEE 279 or IEEE 280 Criteria.
- 13) The Main Steam Safety Valves are arranged such that any condensate in the line between the safety valves and main steam line drains back to the main steam line.
- 14) The Main Steam Piping is arranged to minimize the number of low points.
- 15) The pressure drop at the maximum guaranteed steam flow rating does not f cause the inlet moisture level at the turbine stop valve to exceed 0.5%,
or a thermal analysis of the steam system is performed and the calculated r.oisture level at the turbine stop valve is acceptable to the turbine =
vendor. l
- 16) The drainage system for main steam piping is designed to remove water prior to and during initial rolling of the turbine and during shutdown.
Drain system flow velocity does not exceed 10 ft/sec.
- 17) A drain is located at each low point in the main steam piping system where water may collect during startup, shutdown, or normal operation of a unit. The position of the piping in both hot and cold conditions is
- 19 x 100lb/hr @ 1000 psia saturated steam.
l Amendment No. 12 10.3-4 September 11, 1987
^
considered. In long tuns of piping with no special low point, a low .
point drain is installed at the turbine end of the section. If the main I steam line is split into more than one lead going into the turbine, then each of these leads and the main header are reviewed for low points. The low point drain consists of a drain pot with a minimum diameter of 12 i inches.
- 18) Low point drains are provided upstream of each of the Main Steam Isolation Valves.
- 19) The routing of drain piping is downward, and the slope of all horizontal pipes in tra direction of the flow is downward at a minimum of 1/8 inch per foot of pipe.
- 20) Main Steam System drains are routed to the condenser.
- 21) Main Steam System drains are not connected to manifold serving drains from sources downstream of the turbine throttle valve.
- 22) Two valves are installed in series in each drain line. One of these valves is pneumatically operated and arranged to fail open. This valve is located as close as possible to the main steam header or lead to reduce the amount of water trapped upstream of the closed drain valve.
The second valve is manual and locked open.
- 23) Traps are not used for drains essential to system operation unless they 12 are used in conjunction with a fully automatic redundant drain system.
- 24) All Main Steam System drain lines and valve ports have a minimum inside diameter of one inch to minimize the risk of plugging by foreign material.
- 25) Safety-related Main Steam drains, located in the region from the steam generator to the MSIV, are provided with remote motor operated valves.
Non-safety related Main Steam drains, MSIV to turbine generator, are automatically operated.
- 26) The Main Steam Isolat. ion Valves for each steam generator are arranged such that a maximum of 2,000 cubic feet (total for two steam lines per steam generator) is contained in the piping between each steam generator and its associated MSIVs. This volume includes all lines off of the main steam line up to their isolation valves.
- 27) The main steam lines are arranged such that a maximum of 14,000 cubic feet is contained between the MSIVs and the Turbine Stop Valves. This volume includes all lines off of the main steam line up to their isolation valves.
- 28) A discharge connection is provided on the steam generator main steam line to allow venting of nitrogen gas during steam generator fill operations while still maintaining a pressure of about 5 psig in the steam generator.
Amendment No. 12 10.3-5 September 11, 1987
10.3.2.3 Pioina. Valve. I & C. and Insulation 10.3.2.3.1 Piping
- 1) The main steam piping and its supports and restraints are designed to withstand loads arising from the various operating and design bases events specified in Section 3.9.3.
- 2) The attachment of the main steam piping to the steam generators is designed such that the maximum permissible nozzle loadings are not exceeded.
- 3) Every effort is made to avoid the use of construction materials or protective coatings containing low melting point elements, particularly lead, mercury and sulfur, where these materials may be in contact with the secondary steam system. This is required to reduce to a minimum the .
potential for stress corrosion cracking of Inconel material in the steam l generators.
- 4) The flow area of the main steam piping is sufficient to keep steam velocity below 150 ft/sec.
- 5) Main steam piping layouts that result in 90* elbows, miters, etc., are i minimized.
- 6) The main steam piping material is carbon steel.
- 7) Provisions are made for conveniently supporting the deadweight loads 12 imposed during hydrostatic test of the main steam piping.
10.3.2.3.2 Valves 10.3.2.3.2.1 Main Steam Isolation Valve (MSIV) and MSIV Bypass Valve
- 1) The MSIV is an air operated y globe valve.
- 2) The valves are designed so that no damage due to excessive closure force is incurred during closure under design conditions.
- 3) Backseating of valve stems is provided when the valve is in the full-open position.
- 4) Unrecovered pressure loss from valve inlet to valve outlet at rated flow with the valve full open does not exceed 2 psid.
- 5) The Main Steam Isolation Valve (MSIV) in each main steam line is remotely operated and is capable of maintaining tight shutoff under the main steam line pressure, temperature and flow resulting from the transient conditions associated with a pipe break in either direction of the valves.
Amendment No. 12 10.3-6 September 11, 1987
[ ' 6) The MSIV. leak ' flow does not exceed 0.001. percent of nominal flow at 1200 psia in the forward direction and does not exceed 0.1 percent of nominal flow at 1200' psia in the reverse direction.
- 7) The full open to close stroke time of the MSIVs is 5 seconds or less upon receipt of a Main Steam Isolation Signal (MSIS).
- 8) The MSIVs'are supported such that' the valve body and actuator will not be distorted to such a degree that the valve cannot close or be displaced as
! a' result of pipe break thrust loadings.
- 9) The MSIVs and the MSIV Bypass _ Valves are designed, fabricated and installed such that the requirements for Inservice Testing and Inspection of ASME Section XI,. Subsection IWV can be met.
- 10) The provisions of General Design Criteria 54 and 57 for containment isolation valves are met.
- 11) The MSIV is a fail close valve; upon receipt of a Main Steam Isolation Signal the MSIV closes automatically.
- 12) The MSIV Bypass Valve is a fail close,- power operated valve.
- 13) The MSIVs and ' their supports and the MSIV Bypass Valves and their supports are designed to;' withstand loads arising from the various operating and design bases events as specified in Section 3.9.3. 12
- 14) No single _ MSG Bypass Valve or MSIV Bypass Line has a capacity greater than 1.9 x 10 lb/hr of saturated steam at 1000 psia.
. 1
-15) The MSIV and MSIV Bypass Valves are classified " active" and conform to design requirements meeting the intent of NUREG-0800.
L10.3.2.3.2.2 Main Steam System Safety Valves i F 1)' Each . main steam line is provided with ASME Code, spring-loaded safety valves between the containment and the isolation valves.
- 2) The total relieving capacity of these valves is equally divided between the main steam lines and is based on the ASME Boiler and Pressure Vessel :
Code,Section III.
- 3) The Main Steam Safety Valves are~ a proven design and consistently open fully at a pressure within acceptable limits around the set pressure '
during operability tests. The acceptable limits are based on transient analysis and control system designs.
- 4) The Main Steam Safety Valves are mounted on separate headers connected to the seismically designed portions of the main steam piping. One header is associated with each main steam line.
I Amendment No. 12 10.3-7 September 11, 1987
-- ___ _ _ _ _ _ a
- 5) The Main Steam Safety Valves and their supports are designed to withstand loads arising from the various operating and design bases events as specified in Section 3.9,3.
- 6) The piping and valve arrangement minimizes the loads on the attachment and an analysis confirms the design using ANSI /ASME B.31.1 Appendix 2, "Non-Mandatory Rules for the Design of Safety Valve Installations."
- 7) The opening action of the Main Steam Safety Valve is of a design proven to minimize slight leakage of the valve near the set pressure
(" simmering").
8)- Safety valve set pressure is calculated in accordance with Article NC-7000 of ASME Section III. The following is included: l A maximum allowable pressure of 110% of steam generator design pressure (1200 psia) which equals 1320 psia.
A valve accumulation of 3%.
A valve set pressure tolerance of 1%. l l
Incorporation of the AP between the steam generator nozzles and the safety valves.
6
- 9) The total secondary safety valve capacity is sufficient to pass 19 x 10 l lb/hr at the maximum set pressure. l 12
'10) The gaximum steam flow per secondary safety valve is no greater than 1.9 x 10 lb/hr at 1000 psia.
- 11) The Main Steam Safety Valves are designed, fabricated and installed such that the requirements for Inservice Testing and Inspection of ASME Section XI, Subsection IWV can be met.
- 12) The Main Steam Safety Valves are classified " active" and shall conform to design requirements meeting the intent of NUREG-0800.
~
10.3.2.3.2.3 Main Steam Atmospheric Dump' Valves (ADV)
- 1) Each main steam line is provided with one modulating atmospheric dump valve. This valve is designed to maintain the steam pressure below the lowest setting of the main steam safety valves during emergency shutdowns or plant hot standby conditions. Each valve is capable of holding the plant at hot standby, dissipating core decay and Reactor. Coolant Pump heat, and allowing controlled cooldown from hot standby to Shutdown Cooling System initiation conditions. Each valve is sized to allow a controlled plant cooldown in the event of a line break or tube rupture, which renders one steam generator unavailable for heat removal, concurrent with a loss of normal A.C. power and single active failure of one of the remaining two ADVs. For the preceding conditions, site boundary radiation dose limits are not exceeded. To accomplish the above, each ADV has sufficient capacity to meet the saturated steam flow Amendment No. 12 10.3-8 September 11, 1987
conditions shown in Fig. 10.3.2-1. An ADV with a saturated steam capacity of not less than 950,000 lb/hr at 1000 psia (critical flow assumed) satisfies the steam flow requirements over the range of inlet 1.
pressures capacity shownthan greater in Fig.10.3.g 1.9 x 10 lb/hr at 1000 psia.Also, no single valve has a maximum The valves are manually operated from the main control room or the remote shutdown panel. They fail closed on a loss of electrical power or control signal. Spurious opening of any one valve does not compromise reactor safety requirements.
- 2) During pre-core hot functional testing, the plant must be maintained at standby conditions. To accomplish this, each Atmospheric Dump Valve is capable of controlling flow at 63,000 lb/hr at 1100 psia.
- 3) The valves are mounted on separate headers connected to the seismically designed portions of the main steam piping. One header is associated with each main steam line. One valve is mounted on each header along with ASME Section III code safety valves. The headers are horizontal with the valve mounted vertically upward. The valves vent directly to the atmosphere, with a separate vertical vent stack provided for each val ve.
- 4) The piping and valve arrangement minimizes the loads on the attachment and analysis is performed to confirm the design using ASME/ ANSI B.31.1 Appendix 2, "Non-Mandatory Rules for the Design of Safety Valve 12 Installations."
The ADVs and their supports are designed to withstand loads arising from the various operating and design bases events as specified in Section 3.9.3.
- 5) The ADVs are of a design providing for quick change trim, i.e., the valve internals are designed for removal for maintenance without removing the valve from the line.
- 6) Block valves or isolation valves are provided in the steam line for each Atmospheric Dump Valve.. The block valves are locked open from the Main Control Room and are capable of being remotely and manually positioned from the Main Control Room or from the Remote Shutdown Panel to isolate the Atmospheric Dump Valves.
- 7) The ADVs are provided with accessible handwheels such that each valve may be hand operated in the event of a loss of the normal power supply.
- 8) The ADVs are designed, fabricated and installed such that the requirements for Inservice Testing and Inspection of ASME Section XI, Subsection IWV can be met.
The ADVs are classified " active" and conform to design requirements i
- 9) j meeting the intent of NUREG 0800.
Amendment No. 12 10.3-9 September 11, 1987
i 4
10.3.2.3.3 Instrumentation and Control The control system minimizes the number of instrumentation control functions f and control loops required to perform the essential control functions.
Further, the number of different types of instrumentation and control components used in the system is minimized and coordinated with the remainder of the plant to reduce the maintenance effort and the number of spare parts which must be stocked.
Each sub-system automatic control loop, such as the controis for the bypass valves is analyzed to establish that it meets its functional requirements and .
has adequate stability margin.
10.3.2.3.3.1 MSIV
- 1) Control of the main steam isolation valves is accomplished by a separate system independent of the protection system.
l
- 2) Operator interface to the isolation valve is provided locally, in the main control room (MCR) and at the remote shutdown panel (RSP). The following are provided:
o The capability to manually open and close the valve.
o The capability to test the valve operation (MCR only).
o Valve position indication (open/close indicating lights).
- 3) The MSIVs are interlocked to close upon initiation of a main steam isolation signal (redundant).
12
- 4) Each Main Steam Isolation Valve (MSIV) has two physically separate and electrically independent closure solenoids in order to provide redundant means of valve operation. A MSIS Actuation Signal is provided to each solenoid.
- 5) An electrical or mechanical malfunction of one solenoid does not prevent the MSIV from closing.
- 6) The MSIV Bypass Valve Control Circuits are designeJ, or precautions taken, such that no single electrical f ailure results in the spurious opening of the valves.
- 7) No single failure of the control circuits prevents closure of the MSIV Bypass Valves. The control circuit is designed to the applicable parts of IEEE Std. 279-1971 and IEEE Std. 308-1974.
- 8) The available air supply for valve pneumatic operators is 70 psig minimum to 105 psig maximum. Pneumatic lines and fittings are designed for a minimum pressure of 150 psig.
10.3.2.3.3.2 Atmospheric Dump Valves (ADV)
- 1) Operator interface to the atmospheric dump valve control system is provided in the main control room (MCR) and at the remote shutdown panel (RSP). The following are provided:
Amendment No. 12 10.3-10 September 11, 1987
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o ' The capability to manually close and.pnsition the valve.
o Valve. position' ~ indication (both an4'og . position rad open/close
, indication ..)ights) .
lI 2). No sinhe failure of the control circuits preursts ope ion of at least 3 one : ADV on each steam. generator. The contrelicircuitf:are designed to H the applicable parts of IEEE Std. 279-1971 and IEEE Stri. '308-1974. <
s
- 3) . A safety grade air pressure supply shall be provid2dito c;perate the ADV actuators should the normal air supply fail toi be available. This j
/
safety-grade backup pressure supply may be a nitre u supply or a Type A
' source of air as defined in ANS 59.3/N187 (1984) gi Safety Criteria for '
Control Air Systems'. 1
, [/
10.3.2.3.4 Insul ation ' A,
}
- 1) Non-metallic insulation conforms to NRC Regulatory ' Guide 1.36. The r .) )
chloride and fluoride content of the non-meta)lic insulation are l -
acceptable as shown in Regulatory Guide 1.36a.iTests are made on y' yf p ,
representative samples of the non-metallic therma'} nnulation to certify .p t that the maximum chloride and fluoride contents 'are' rot exceeded. All water used. in the fabrication of non-metallic thertal insulation is p demineralized or distilled water. A '
/
- 2) .The insulation . thickness 'is selected to minimize the heat load on the containment ventilation an_d cooli_np y sy_ stem.
j A thermal transference of 12 not more than 0.14 Btu-br *F -ft of insulated component surface ,
area is used as a design basis for insulation. )
10.3.3 SAFETY EVALUATION
- 1) 'A failure of any main steam line or malfunction of a valve in the system
- will not: ( q
- a. Reduce flow capability of the Emergency Feedwater System below the /
minimum required.
Prohibit function, of an Enginekred Safety Feature.
- b. -
u <
of ,
- c. Initiate a loss-of-coolant accident.
- d. Cause uncontrolled flow from more than one steam generator.
- e. Jeopardize Containment integrity. ' C
- 2) The Main Steam System delivers t'he genercted steam from the outlet of the steam generators to the various system components throughout the Tubine Building without incurring 4xcessivet pressure losses. Steam is generated at essentially dry and sattrated con 11tions. Functional requirements of the system are as follows:
y I
Amendment No. 12 10.3-11 September 11, 1987
e- -
4 734 3
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> a. Achieve , minimum yessure drop between the steam generators and the N , turbine steam stop valves.
n ib'.Ir Asrure similar condici6hs between each steam stop valve and between each
}steamgenerator.
1
~ ,
m c.j Provide adequate piping flexibility ta acconrnodate thermal expansion. . 12
.w l- 'd. ' Assure adequate draining proviylons for startup and for operation with I' saturated steam.
- 3) SafetyrelatedportionsoftheMainStiamSystemarecontainedinseismic category I structures and are designed and located to protect against er:vironmental hazards such as wind, tornadoes, hurricanes., floods,
,1 afisiles, and the effects of high and moderate energy pipe rupture as 4
g4 Mailed in Chapter 3.
10$) INSPECTION AND TESTING REQUIREMENTS c 1) ASME'Section III Code, Class 2 pintog is inspected and tested in accordance with ASME Code Section 3D and XI. ANSI B31.1 piping is inspected an,d f.ested in accordance with Paragraphs 136 and 137.
- 2) To pemit testing for pH and the existence of foreign substances, sample connections are provided in the steam line piping between the steam generator nozzles and equalization header.
- 3) Duri[g initial startup and dring neriods- of unit shutdown, the tripping
-o mechanisms for the ma'p steam is'olation valves are tested for proper 34 *, operation in - accordMce ,4 f th the Technical Specifications. The valves
- /.
are periodically during pierd inservf.p(nl tested for leakage accordance withand ASME freedom CodeofSection movement XI.
Subsection-IWV. c$er[aHon-
! s j 12
- 4) The 'secondFyj ssfety valves are tested during initial startup or during shutdown operasion' by checking the actual lift and closing pressures of the valves in comparison to the required design opening and closing pressuresinaccordancewith3.rAECode,SectionXI,SubsectionIWV.
- 5) ASME Code Section XI, Subsectlen IWV requirements for inservice testing and inspection'oP auclear safety related valves apply to the atmospheric dump and atmospheric dump isolation valves.
10.3.5 SECONDARY WATER CHEMISTRY 10.3.5.1 Chemistry Control B311s_
Steam generator secondary side w'ater chemistrv control is accomplished by:
- a. Close control of the feadwate[ to limit the amount of impurities which
'4 can be introduced into the steam generator.
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- I Amendment No. 12
'10.3-12 September 11, 1987
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- b. Continuous blewdown of the steam generator to reduce the concentrating effects of the storm generator.
- c. Chemical addition to establish and maintain an environment which afnimizes systen." corrosion.
- d. Preoperational_cNaningofthefeedwatersystem.
- y e. Minimizing feedwater cy,ygen content prfor to entry into the steam generator.
Secondary water chemistry is blsed on the zero solids treatment method. This !
'O method employs the use of volatile additives to maintain system pH and to scavenge dissolved oxygen which may be present in the feedwater.
~
A neutralizing amine is added to establish and maintain alkaline conditions in the feedtr61n. Neutralizing amines which can be used for pH contPol are
, ammonia, morpholine, and cyclohexylamine. Amonia should be used in plants employing condensate polishing to avoid resin fouling. Although the amines are volatile and will not concentrate in the steam generator, they will reach an equilibrium level which will establish an alkaline condition in the steam l' generator.
Hydrazine is added to scavenge dissolved oxygen which may be present in the feedwater. Hydrazine also tends to promote the formation of a protective oxide layer on metal surfaces by keeping these layers in a reduced chemical state.
Both the pH agent and hydrazine can be injected continuously at the discharge headers of the condensate pumps or condensate demineralized, if installed.
These chemicals are added as necessary for chemistry control, and can also be added to the upper steam generator fe9.d line when necessary.
Operating chemistry limits for tecondary steam generator water and feedwater and condensate are giver, in Tables 10.3.5-1 and 10.3.5-2.
The limits stated are divided into two groups: normal; and, abnomal. The limits provide high quality chemistry control and yet permit operating flexibility. The normal cfiemistry conditions can be maintained by any plant 10 ,
cperating with little or no condenser leakage. The abnomal steam generator i limits are suggested to permit operations with minor system fault conditions until the affected component can be isolated and/or repaired.
The following procedures are recommended for protection against secondary 12 system and steam generator corrosion:
j Rnen the normal range is exceeded, immediate investigation of the problem should be initiated, sampling frequency increased to the abnormal level (at least twice per 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> shift) and blowdown fricreased to one (1) percent of the 10 main steaming rate. The. problem should be corrected and the parameter (s) returned to the normal range within end week., If this cannot be done, and the parameter has a listed abnormai range, power should be reduced to 25% as if .
the abnornal range had been exceeded. !
Amendment No. 12 10.3-13 September 11, 1987 i
When the abnormal range is exceeded, power should be reduced to the lowest value (maximum of 25".) consistent with automatic operation of the feed system.
Continued plant operation .is then possible while corrective action is taken.
Power reduction should be initiated within four hours of exceeding the 10 abnormal range. The problem should be corrected and the parameter (s) returned to the normal range within one hundred (100) hours. If this cannot be done, the unit.should be shut down.
Draining or flushing of the steam generators will be necessary to reduce the 5 impurity concentration.
10.3.5.2 Corrosion Control Effectiveness Alkaline conditions in the feed train and the steam generator reduce general corrosion at elevated temperatures and tend to decrease the release of soluble corrosion products from metal surfaces. These conditions promote the i formation of a protective. metal oxide film and thus reduce the corrosion ,
products released into the steam generator.
Hydrazine also promotes the formation of a metal oxide film by the reduction f of ferric oxide to magnetite. Ferric oxide may be loosened from the metal surfaces and be transported by the feedwater. Magnetite, however, provides an adherent protective layer on carbon steel surfaces. l The removal of- oxygen from the secondary water is also essential in reducing corrosion. Oxygen dissolved in water causes general corrosion that can result in pitting of ferrous metals, particularly carbon steel. Oxygen is removed from the steam cycle condensate in the main condenser deaerating section and j by .the full flow feedwater deaerator which is a portion of the low pressure 12 ,
feedwater heaters. Additional oxygen protection is obtained by chemical injection of hydrazine into the condensate stream. Maintaining a residual ,
level of hydrazine in the feedwater ensures that any dissolved oxygen not i removed by the main condenser is scavenged before it can enter the steam l generator. j
~
The presence of free hydroxide (OH ) can cause rapid corrosion (caustic stress corrosion) if it is allowed to concentrate in a local area. Free hydroxide is avoided by maintaining proper pH control, and by minimizing impurity ingress in the steam generator.
Zero solids treatment is a control technique whereby both soluble and ,
insoluble solids are excluded from the steam generator. This is accomplished !
by maintaining strict surveillance over the possible sources of feed train contamination (e.g: Main Condenser cooling water leakage, air inleakage and j subsequent corrosion product generation in the Low Pressure Drain System, '
etc.). Solids are also excluded, as discussed above, by injecting only volatile chemical s to establish conditions which reduce corrosion and, i therefore, reduce the transport of corrosion products into the steam .
generator. Reduction of solids in the steam generator can also be I accomplished through the use of full flow condensate demineralization.
In addition to minimizing the sources of contaminants entering the steam generator, continuous blowdown is employed to minimize their concentration.
Amendment No. 12 10.3-14 September 11, 1987
These systems are discussed in Section 10.4.6. With the low solid levels which result from employing the above precedures, the accumulation of corrosion deposits on steam generator heat transfer surfaces and internals is
' limited. Corrosion product formation can alter the thermal hydraulic 12 performance in local regions to such an extent that deposits create a nechanism which allows impurities to concentrate to high levels, and thus could possibly cause corrosion. Therefore, by limiting the ingress of solids into the steam generator, the effect of this type of corrosion is reduced.
Because they are volatile, the chemical additives will not concentrate in the steam generator, and do not represent chemical impurities which can themselves cause corrosion.
-10.3.6 STEAM AND FEEDWATER SYSTEM MATERIALS 10.3.6.1 Fracture Touchness Materials are in compliance with Sections II and III of the ASME Boiler and Pressure Vessel Code with respect to fracture toughness and meet the requirements of ASME Section III, articles NB-2300, NC-2300, and ND-2300.
10.3.6.2 Materials Selection and Fabrication 12
- 1) Materials used are included in Appendix I of Section III of the ASME Code.
- 2) No austenitic stainless steel piping material is used in these systems.
- 3) Cleaning and acceptance criteria are based on the requirements of ANSI N45.2.1-73 and the recommendations of NRC Regulatory Guide 1.37.
- 4) Low-alloy steels are not used in the systems for piping materials.
- 5) The degree of compliance with NRC Regulatory Guide 1.71, " Welder Qualification for Areas of Limited Accessibility", is discussed in Section 1.8.
- 6) Nondestructive examina. tion procedures for tubular products conform to the requirements of the ASME Code,Section III, NC-2000 for Clas s 2 materials.
Amendment No. 12 10.3-15 September 11, 1987
(
TABLE 10.3.5-1 OPERATING CHEMISTRY LIMITS FOR SECONDARY STEAM GENERATOR WATER Normal I1) Abnormal
' Variable .___
Specifications _ Limits pH (mixed system)( ) 8.5 - 9.0 (copper free) 9.0 - 9.5(5)
Cation Conductivity ( ) < 0.8 pmhos/cm 0.8-2.0 pmhos/cm Silica < 300 ppb Chloride . < 20 ppb 20-100 ppb Sodium I4) < 20 ppb 20-100 ppb Sulfate < 15 ppb 15-100 ppb 10 NOTES:
(1) Normal specifications are those which should be maintained by continuous steam generator blowdown during proper operation of secondary systems.
l(2) A mixed system is any secondary system containing copper alloy components.
- (3) If the imediate shutdown limit of 7.0 pmhos/cm is exceeded, the unit.
should be shut down within four hours.
(4) If the.imediate shutdown limit of 500 ppb is exceeded, the unit should be shut down within four hours.
- (5) -In plants where condensate polishers are in operation, the pH of a copper-free system can be controlled to a value of > 8.8, wi'h action 12
-required at < 8.8.
1 i
i Amendment No. 12 September 11, 1987
\; _ - _ _ _ _ _ _ - _ - _ _ _ - _ - _ -
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TABLE 10.3.5-2 OPERATING CHEMISTRY LIMITS FOR FEEDWATER AND CONDENSATE
. ' Normal (1)
Variable Specifications pH
- a. Mixed system 8.8 - 9.2 b.= Copper-free system- 9.3 - 9.6(6)
Conductivity (Intensified cation)(Feedwater) < 0.2 pmhos/cm Hydrazine (Feedwater) 10 - 50 ppb Dissolved Oxygen (Feed) < 3 ppb (Condensate)(2) < 10 ppb Sodium I3) < 3 ppb Iron (Feedwater) < 20 ppb to pH Control Additive (5)
Copper' (Feedwater)I4) < 2 ppb NOTES: >
(1) Normal specifications are those which should be maintained during proper oparation of secondary systems.
(2) The condensate abnorm.a1 limit is 10-30 ppb, but the requirement for imediate shutdown does not apply even if the problem is not corrected within 100 hrs.
(3). For the condensate, sodium is monitored at each condenser hot well.
(4) Analysis not required for copper-free systems.
(5) Limit is dependent upon pH.
(6) In plants where condensate polishers are in operation, the pH of a 12 copper-free system can be controlled to a value of > 9.0, with action required at < 9.0..
Amendment No. 12 September 11, 1987
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2 3. 0 - -
x SE ._
E a 2.0 - -
31.0 - -
u e,n I e t i I 1 0 200 400 600 800 1000 1200 1400 INI.ET PRESSURE (PSIA) 1 j
\
I MATE FIGURE 10.3.2-1 Atmospheric Dump Valve Flow Requirements Amendment No. 12
{ September 11, 1987
10.4 OTHER FEATURES OF STEAM AND POWER CONVERSION SYSTEM 10.4.1 MAIN CONDENSER 10.4.1.1 Desian Bases
- 1) The main condenser is designed to condense the low pressure turbine exhaust steam so it can be efficiently pumped through the steam cycle.
The main condenser also serves as a collection point for the following:
- a. Feedwater heater drains and vents.
- b. Condensate and Feedwater System makeup.
- c. Condenser steam air ejector inner-condenser drains.
- d. Miscellaneous equipment drains and vents.
- 2) The main condenser is also designed to condense up to 55 percent of the lllllh full load main steam flow bypassed directly to the condenser by the Turbine Bypass System. The steam is bypassed to the main condenser in case of a sudden load rejection by the turbine generator or a turbine trip, and at plant startup and shutdown as described in Subsection 10.4.4. The main condenser hotwells serve as a storage reservoir for the Condensate and Feedwater Systems with sufficient volume to supply maximum condensate flow for 5 minutes. The main condenser is also designed to provide for removal of noncondensable gases from the condensing steam by to' the Main Vacuum System described in Section 10.4.2. Heat is removed from the main condenser by the Condenser Circulating Water System.
10.4.1.2 System Description The final design and layout of the condenser is described in the site-specific SAR supplement. The following functional requirements are to be met to ensure a reliable system:
- 1) The condenser is designed in accordance with Heat Exchanger Institute Standards. The condenser is a multi-pressure design, with two or more parallel circulating water flow paths. Tubing is of commercially available lengths. The design does not preclude shop pre-fabrication.
- 2) The condenser tube material is type 304L stainless steel for fresh water applications with chloride levels below 200 ppm. For higher chloride levels up to 500 ppm, type 316L stainless steel tubing is used. A higner grade of stainless steel (such as 904L or AL-6X) is used for chloride levels between 500 and 800 ppm. For brackish or salt water applications containing high concentrations of dissolved solids (1000 ppm) or chlorides (greater than 800 ppm) or water contaminated by sewage discharges, titanium tubing is used.
- 3) Tube gauge with stainless steel is not thinner than 22 BWG. Tube gauge with titanium is not thinner than 23 BWG. Condenser design precludes or Amendment No. 12 10.4-1 September 11, 1987 9
minimizes. steam . impingement forces on the condenser tubes for normal
. operation and turbine bypass valve quick opening events. Tube support
' plates are designed to minimize tube' vibrations.
- 4) Provisions for chemical injection into the! condenser lfor ~ biofouling l
control is included 'in accordance with site specific requirements and applicable regulations.'
- 5) Means are' provided to protect the tubes from pitting during periods of condenser shutdown.
- 6) Tube sh'eets are specified as follows:
o For.304L stainless steel tubes, use 304L stainless-clad carbon-steel tube sheets.
o For 316L stainless steel tubes, use 316L stainless-clad carbon steel.
o For titanium tubing, use titanium-clad carbon steel tube sheets.
7)' Double tube sheets or welded tube to tube sheet joints are provided.
8)- Leak- detection trays are included at all tube- to tube sheet interfaces.
Provisions for early leak detection are provided at tube sheet trays and ' .
in each hotwell section. The hotwell is divided into sections to allow i for leak detection and location. 12
- 9) The condenser is designed to deaerate the condensate during startup and ;
normal operation. The design also deaerates any drains which enter the condenser.
- 10) The condenser and circulating water system are designed to permit :
isolation of a portion of the - tubes - (segmented condenser) to. permit i repair of leaks and cleaning of water boxes while operating at reduced power.
- 11) The condenser is capable of being filled with water for a hydrotest.
Provisions are made to allow draining and cleaning of the hotwell.
- 12) A stainless steel expansion joint and a water seal trough between the.
condenser and the turbine are provided.
- 13) An automatic condenser cleaning system is provided.
- 14) ' Heater shells and piping installed in the condenser neck are located ;
outside of the turbine exhaust steam high velocity regions and within the 1 limits specified by the turbine supplier. Internal piping is as short and straight as possible and all steam extraction piping slopes downward toward the heater shells.
Amendment No. 12 10.4-2 September 11, 1987
- 15) Sections of heater shells and piping that are located inside the condenser and nonnally operated with a full load inside temperature of about 90*C (194*F) or more shall be lagged. The lagging is made of stainless steel at least 1/16" thick and is designed consistent with proven practice.
- 16) The condenser neck fluid design is based on air tests, modelling the steam flow path from the LP turbine exhaust hoods to the condenser tube bundles. The test model accounts for the condenser neck heaters and associated piping and for the neck major structural elements, lines and baf fles. The tests cover all major operating modes including operation with steam bypass dump and operation with one tube bundle out of service. ,
- 17) The change in liquid inventory in the steam generators, as plant load changes, is considered in designing the Condensate System and sizing the !
condenser hotwell. On a steady state basis, the steam generator mass !
decreases by (LATER) pounds between 0 percent and 100 percent load.
10.4.1.3 Safety Evaluation The main condenser is normally used to remove residual heat from the Reactor Coolant System during the initial cooling period after plant shutdown when the i main steam is bypassed to the condenser by the Turbine Bypass System. The condenser is also used to condense the main steam bypassed to the condenser in '
the event of sudden load rejection by the turbine-generator or a turbine trip.
In the event of load rejection, the condenser will condense 55 percent of full 12 load main steam flow bypass to it by the Turbine Bypass System without tripping the reactor. If the main condenser is not available during normal plant shutdown, sudden load rejection, or turbine trip, the spring-loaded safety valves can discharge full main steam flow to the atmosphere to protect the Main Steam System from overpressure. Safe reactor shutdown may then be achieved by use of the atmospheric dump valves. Nonavailability of the main condenser considered here includes failure of the circulating water pumps to supply cooling water, or loss of condenser vacuum for any reason.
During normal operation and shutdown, the main condenser will have no radioactive contaminants inventory. Radioactive contaminants can only be obtained through primary to secondary system leakage due to steam generator tube leak. A discussion of the radiological aspects of primary to secondary leakage, including operating concentrations of radioactive contaminants, is included in Chapter 11. There is no hydrogen buildup in the main condenser.
The main condenser is non safety-related.
10.4.1.4 Tests and Inspections The main condenser is tested in accordance with the Heat Exchanger Institute Standards for Steam Surface Condensers. Proper operation of the system after startup will assure system integrity and further testing of components in continuous use will not be necessary. Periodic visual inspections and preventive maintenance are conducted following normal industrial practice. l See the site-specific SAR for additional test and inspection applications. l Amendment No. 12 10.4-3 September 11, 1987 )
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10.4.1.5 Instrumentation Acolication All of the instrumentation for this system is operating instrumentation and none is required for safe shutdown of the reactor. See the site-specific SAR for additional instrumentation applications.
10.4.2 MAIN VACUUM SYSTEM 10.4.2.1 Desian Bases The Main Vacuum System is designed to:
- a. Remove air and other noncondensable gases from the condenser,
- b. Maintain adequate condenser vacuum for proper turbine operation during startup and normal operation.
10.4.2.2 System Description The Main Vacuum System consists primarily of vacuum pumps and steam jet air ejectors (SJAE) which are used to pull a vacuum. on the main condenser. See the site-specific SAR for detailed information and an overall system flow 12 diagram.
There is no direct connection between the Main Vacuum System and the Reactor Coolant System; therefore, normal function of one will not directly affect the other.
10.4.2.3 Safety Evaluation The system is not assigned a safety class as it serves no plant safety i function. It is not required for safe shutdown of the plant.
10.4.2.4 Tests and Inspections j The system is fully tested and inspected before initial plant operation and is subject to periodic inspections after startup. System perfonnance will indicate proper function o.f the system and any system malfunction will be corrected by appropriate means. See the site-specific SAR for additional test and inspection applications.
10.4.2.5 Instrument Application The Main Vacuum System includes sufficient instrumentation to assure proper operation. All of the instrumentation for this system is operating instrumentation and none is required for safe shut-down of the reactor. See the site specific SAR for additional instrumentation applications.
10.4.3 TURBINE GLAND SEALING SYSTEM (Later - pending completion of EPRI Chapter 13) 12 Amendment No. 12 10.4-4 September 11, 1987
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- 10.4.4- TURBINE BYPASS SYSTEM 10.4.4.1 Desian Bases The turbine bypass system has no safety functions. The turbine bypass system, operating in conjunction with the reactor power cutback system (Section 7.7.1.1.6), is designed to accomplish the following functions:
- a. ' Accommodate. load rejections of any magnitude without tripping the reactor or lifting primary.or secondary safety valves.
- b. Control NSSS thermal conditions to prevent the opening of safety valves following a unit trip.
- c. Maintain the NSSS at hot zero power conditions.
- d. Control NSSS thermal conditions when it is desirable to have reactor power greater than turbine power, e.g., during turbine synchronization.
- e. . Provide pressure limiting - control during the loss of one out of two feedwater pumps.
- f. Provide a CEA Automatic Motion Inhibit (AMI) signal when turbine power and reactor power fall below selected thresholds; provide AMI signal below 15 percent reactor power to block automatic control of the reactor below this power level.
- g. Provide a means for manual control of Reactor Coolant System (RCS) temperature during NSSS heatup or cooldown.
- h. Provide for operation of the turbine bypass valves in a manner that minimizes valve wear and maintains controllability.
- 1. Provide for operation of the turbine bypass valves in a sequence which, by proper applicant arrangement of valving to the condenser, limits the flow imbalance between condenser shells to the flow capacity of 1 valve when all turbine bypass valves and condenser shells are available.
J.- Include redundancy in the design so that neither a single component failure nor a single operator error result in excess steam release.
- k. Provide a condenser interlock which will block turbine bypass flow when unit condenser pressure exceeds a preset limit.
The environmental design criteria are listed in the site-specific SAR.
10.4.4.2 System Description and Operation 10.4.4.2.1 General Description The turbine bypass system consists of the Ste>m Bypass Control System, the turbine bypass valves and associated piping and instrumentation. The Steam Bypass Control System is described in Section 7.7.1.1.5.
1 10.4-5
10.4.4.2.2 Piping and Instrumentation A typical turbine bypass system consisting of eight turbine bypass valves ,
located in lines branching from each main steam line, downstream of the main steam isolation valves and conr.ecting to the main condenser is shown in Figure 10.1-1.
10.4.4.2.3 Turbine Bypass Valves The turbine bypass valves are air operated valves with a combined capacity of 55% of the total full power steam flow at normal full power steam generator pressure (1000 psia). The valves are normally controlled by the steam bypass 12 control system but are capable of remote or local manual operation. When 10 operating automatically the valves modulate full open or full close in a minimum of 15 seconds and a maximum of 20 seconds. In response to a quick opening signal from the Steam Bypass Control System, they are designed to open in less than 1 second. In response to a closing signal from the steam bypass l12 control system, they are designed to close in 5 seconds. The system is capable of controlling at flows as low as 63,000 lb/hr in order to permit operation at hot standby during pre-core hot functional testing.
10.4.4.2.4 System Operation The turbine bypass system takes steam from the main steam lines upstream of ,
the turbine stop valves and discharges it directly to the main condenser, !
bypassing the turbine ge.nerator. During nomal operation, the bypass valves are under the control of the steam bypass control system, as discussed in Section 7.7.1.1.5. During cooldown or hot shutdown, the turbine bypass valves may be actuated individually from the main control room to regulate steam generator pressure and reactor coolant temperature change.
4 10.4.4.2.4.1 System Performance
- 1. The total TurDine Bypass Valve capacity is 55% of total full power steam flow at normal full power steam generator pressure (1000 psia). This relieving capatity in conjunction with the Steam Bypass Control and Reactor Power Cutback Systems allows a turbine full load rejection without causing a reactor trip or lifting the primary and/or secondary safety valves. g
( 2. No6 single Turbine Bypass Valve has a maximum capacity greater than 1.9 x 10 lb/hr at 1000 psia.
- 3. Turbine Bypass Valves are fail close valves to prevent uncontrolled bypass of steam to the condenser.
- 4. The Turbine Sypass Valve operating speeds are as follows:
- a. The valves stroke from the full closed po ition to the full open l position and from full open position to full closed position in 15 l to 20 seconds when a modulation signal is applied to the valve control system.
6 Amendment No. 12 10.4-6 September 11, 1987
- b. The valves stroke from the full closed position to the full open position in less than 1 second when a quick opening signal is applied to the valve control system.
- c. The valves stroke from the full open position to the full closed position within 5 seconds when the permissive gating signal is removed from the valve control system.
- 5. The Turbine Bypass Valves and their supports are designed to withstand loads arising from the various normal operating and design bases events as specified in Section 3.9.3.
- 6. The as-built pressure drop between the steam generator outlet nozzles and each Turbine Bypass Valve is provided to CE to evaluate the actual relieving capacity.
- 7. During pre-core hot functional testing, the plant must be maintained at 12 hot standby conditions. To accomplish this, at least one Turbine Bypass valve is capable of controlling flow at 63,000 lb/hr at 1100 psia. i
- 8. The Turbine Bypass Valve Control Circuits are designed, or precautions taken, such that no single electrical failure results in the opening of more than one valve.
- 9. The Turbine Bypass Valves should be equipped with hand-wheels to permit manual operation at the valve location.
- 10. The Turbine Bypass Valves are arranged such that operation of any valves results in approximately equal blowdown from each steam generator.
10.4.4.3 Safety Evaluation The valves in the turbine bypass system are designed to fail closed to prevent uncontrolled bypass of steam to the condenser. Should the bypass valves fail to open on command, the secondary safety valves provide main steam line overpressure protection. The power-operated atmospheric dump valves provide a means for controlled cooldown of the reactor. The secondary safety valves and power-operated atmospheric dump /alves are described in Section 10.3.2.
l12 Should the condenser not be available as a heat sink, an interlock will prevent opening, or if opened, will close the turbine bypass system valves, j The secondary safety valves and power-operated atmospheric dump valves are I used to control the load transient, if the bypass valves are disabled.
l Because the ASME Code safety valves provide the ultimate overpressure protection for the steam generators, the turbine bypass system is defined as a control system and is designed without consideration for the special requirements applicable to protection systems. Failure of this system will have no detrimental effects on the Reactor Coolant System.
Operation of the turbine bypass system has no adverse effects on the environment since steam is bypassed to the condenser, the heat sink in use during normal operation.
Amendment No. 12 10.4-7 September 11, 1987 J
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' This system is not required for the safe shutdown of the reactor and has no safety function. 12 10.4.4.4 Inspection and Testina Requirements This system is non safety-related.
t 10.4.4.5 Instrumentation Acolication ,
The - control system for the ' Turbine Bypass System is d' escribed in Section 7.7.1.1.5 (Steam Bypass Control System).
10.4.5 CIRCULATING WATER SYSTEM (Later - pending completion of EPRI Chapter 8) 12 10.4.6 CONDENSATE CLEANUP SYSTEM 10.4.5.1 Desian Basis The Condensate Cleanup System (CCS) is an integral part of the Condensate System. The CCS is designed to remove dissolved and suspended impurities which can cause corrosion damage to secondary system equipment. The CCS also removes radioisotopes which might enter the system in the event of a primary to secondary steam generator tube leak. The condensate polishing demineralizers (CPD) will also be used to remove impurities which could enter the system due.to a condenser circulating water tube leak.
10.4.6.2 System Description The condensate cleanup system utilizes a side stream full condensate flow polisher, located downstream of the condensate pumps.
12 The final design and layout of the condensate cleanup system are described in the site-specific SAR. The following functional requirements are to be met to ensure a reliable system.
- 1. The polishing system ,is sized to meet the chemistry requirements for continuous operation specified in Section 10.3.5 while operating with a condenser leak of 0.001 gpm and to maintain water quality during an orderly unit shutdown (not longer than 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />) with a leak of 0.1 gpm irregardless of the type of cooling water.
- 2. The number and sizing of the ion exchangers are such that the functional requirements can be met while permitting the replacement of resin in one ion exchanger at a time. l
- 3. Plant features are provided to facilitate replacement of ion exchange resin. No ion exchange resin regeneration system is provided.
- 4. Resin traps are installed down stream of each ion exchanger.
Amendment No. 12 10.4-8 September 11, 1987
2
- 5. Design flow rates through the demineralizers are 40 gpm/ft or less.
Minimum bed height is 3 ft.
- 6. The demineralized outlet lines are fitted with individual flow regulating valves.
- 7. The system design permits full ficw recirculation through each ion exchanger for cleanup and verification of resin bed performance after resin replacement and prior to alignment within the system.
- 8. Ion exchanger isolation valve and recirculation valves are designed to permit slow, controlled opening to minimize hydraulic surges on the resin bed. 12 10.4.6.3 Safety Evaluation This system is non safety-related.
10.4.6.4 Insoection and Testina Requirements This system is non safety-related.
10.4.6.5 Instrumentation Applications This system is non safety-related.
10.4.7 CONDENSATE AND FEEDWATER SYSTEMS 10.4.7.1 'Desian Basis The Condensate and Feedwater Systems are designed to return condensate from the condenser hotwells to the steam generators. In addition, the systems include a number of stages of regenerative feed and condensate heating and provisions for maintaining feedwater quality.
The entire Condensate System is non safety-rel ated. The portions of the Feadwater System that are required to mitigate the consequences of an accident and allow safe shutdown of the reactor are safety-related. The safety-related 12 portions of the system are designed in accordance with the following design bases:
- 1) The system is designed such that failure of a feedwater supply line coincident w1!.h a single active failure will not prevent safe shutcown of the reactor.
- 2) The system components are designed to withstand the effects of and I perform their safety functions during a safe shutdown earthquake.
- 3) Components and piping are designed, protected from, or located to protect against the effects of high and moderate energy pipe rupture, whip, and jet impingement which are not eliminated by leak-before-break analysis.
1 1
Amendment No. 12 10.4-9 September 11, 1987
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t ._ _ _ _ _ - _ _ _ _ _ _ _ _ _ _
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- 4) The system is designed such that adverse environmental conditions such as tornados, floods, and earthquakes will not impair its safety function.
- 5) The system is designed such that the loss of offsite power will not prevent safe shutdown of the reactor.
- 6) The main feedwater lines are restrained or isolated to prevent damage to the reactor coolant pressure boundary and containment in the event of a feedwater pipe rupture that is not eliminated by leak-before-break analysis. '
10.4.7.2 System Description s
Three 50 percent capacity motor-driven condensate pumps (two ope;(ating and one standby) deliver condensate from the condenser hotwell to side \ stream full flow condensate polisher cells (See Section 10.4.5) followed by the. condenser air efectors, the gland seal condenser, and four stages of three parallel feedwater heaters to the deaerator.
- Three 50 percent capacity motor-driven feedwater booster pumps (two operating and one standby) deliver condensate from the deaerator storage tank to the suction of the main feedwater pumps.
Three 50 percent capacity turbine-driven main feedwater pumps (two operating and one standby) deliver feedwater through two stages of two parallel high pressure feedwater heaters to a single feedwater distribution header. (A 12 motor driven feedwater pump is utilized for startup.) At this point, feedwater flow is divided into two to each steam generator.
Each steam generator has one downcomer feedwater nozzle and two economizer nozzles. At 100% power, the downcomer feedwater line is sized for a flow of at least 10% of full power flow at the normal full power steam generator pressure. Each economizer feedwater line is sized for a total flow of 50% of full power flow at normal full power steam generator pressure. During plant startup, the downcomer feedwater line is sized to accomodate all feedwater flow below the temperature of 200*F.
The manner in which the feedwater flow is delivered to the steam generator varies with re ctor power:
- 1) when reactor power is from 0% to 15% of full power, all feedwater is delivered to the steam generator through the downcomer line;
- 2) when reactor power is above 15% and below 50%, all feedwater is delivered to the steam generator through the economizer; and,
- 3) when the reactor power is above 50% of full power, the feedwater flow is split, so that 10% of the full power main steam rate goes to the downcomer as feedwater while the remainder of the feedwater is injected into the economizer.
l l
l Amendment No. 12 10.4-10 September 11, 1987
1 Two check valves in series are located in the downcomer feedwater lines and economizer feedwater lines to provide abrupt, complete termination of reverse feedwater flow. Redundant isolation valves are provided in both the economizer feedwater lines and the downcomer feedwater lines. These valves are active and provice complete termination of forward feedwater firi within 5 seconds after receipt of an MSIS. The safety analysis of these valves is described in Chapter 15. -
All piping and valves from the steam generator nozzles to the second main feedwater isolation valve in both the economizer and downcomer feedwater lines <
are seismic Category I and are designed to ASME Code Section III, Class 2 requirements.
One feedwater control valve on each steam generator is provided to control feedwater flow to the economizer nozzles and one control valve on each steam j generator is provided to control feedwater flow to the downcomer nozzle.
These valves are automatically or manually controlled by the Feedwater Control System described in Section 7.7.1.1.4 to control the proper feedwater flow to each steam generator and maintain proper steam generator level from startup through and including full power operation.
The following standardized functional descriptions and requirements present the system configuration necessary to meet the NPM licensing, safety, and reliability requirements. The final detailed design and layout of the condensate and feedwater systems are described in the site-specific SAR.
10.4.7.2.1 System Performance 12
- 1. Steam flow per steam generator as a function of power is shown on Figure 10.4.7-1. Feedwater flow requirements at any given power level are equal to the total steam flow plus approximately 172,000 lb/hr, which allcws a continuous blowdown rate of 1% of the total steam flow at normal full power steam generator pressure (1000 psia).
- 2. Steam generator pressure as a function of power is given in Figure 10.4.7-2.
- 3. Feedwater temperature at 100% power is 450* + 0*F/-10*F.
- 4. Feedwater temperature is equal to or greater than 200*F prior to initiation of feedwater flow to the economizer nozzles during plant startup. The 200*F feedwater temperature is achieved prior to reaching 15% power. All feedwater at a temperature lower than 200*F is directed to the downcomer feedwater nozzle. This does not include post turbine trip conditions.
- 5. The feedwater flow split between the economizer nozzles and the downcomer nozzle throughout ascent in power is shown on Figure 10.4.7-3.
- 6. The Main Feedwater System provides the proper flow to the steam generators under the operating and design conditions contained in Section 7.7.1.1.4, Feedwater Level Control System.
Amendment No. 12 10.4-11 September 11, 1987
- 7. The : chemistry requirements of Section 10.3.5 apply during all- phases of plant operation including startup, hot standby and cooldown.
- 8. The change' in liquid inventory in the steam generators, as plant load changes, ~ amounts to a decrease of '(LATER) pounds between 0 percent and 100 percent load. In designing the Condensate System and sizing the condenser hotwell, this difference is considered.
- 9. Plant operation can continue at reduced power with loss of one operating feedwater~ pump.
i
- 10. Plant operation can continue at 100% power with loss of one operating condensate or feedwater booster pump.
- 11. .The feedwater and condensate system is designed to avoid erosion damage.
The design and layout of piping systems considers the effect on the piping material from fluid velocity, bend location and the location of flash points. .The following velocity limits are recommended:
a) Pipe velocity 5 20 ft/sec; b) Feedwater heater inlet flow velocity 512 ft/sec; and, c) Condensate pump suction line velocity 5 5 ft/sec.
10.4.7.2.2 System Arrangement
- 1. Redundant Feedwater System Isolation Valves meeting single failure criteria aro provided in any feedwater piping interconnecting the steam 12 generators to preclude blowdown of both steam generators following a postulated pipe rupture.
- 2. Redundant Feedwater System Isolation Valving is provided in both the economizer feedwater lines and the downcomer feedwater lines such that abrupt complete termination of an existing reverse flow condition is accomplished with consideration of a single failure. (Check valves are considered to be an acceptable means of achieving the above.)
- 3. The Main Feedwater Isolation Valves are located outside of the containment building as close to the containment wall as possible as required by General De' sign Criterion 57 Closed Systems Isolation Valves. l
- 4. The Main Feedwater Isolation Valves for each steam generator are arranged such that a maximum of 500 cu. ft. of fluid is contained in the piping between each steam generator and its associated isolation valves. This
, volume also includes the volumes between the Redundant Main Feedwater Isolation Valves and the volumes up to the respective isolation valves of i
all lines off of the main feedwater lines downstream of the Main Feedwater Isolation Valves for which a mechanism exists for getting the ,
fluid into the main feedwater line (e.g., gravity, flow or flushing). 1
- 5. A 90* or 45* elbow facing downward is attached to each feedwater nozzle.
Such a precaution aids in the prevention of water hammer.
- 6. To allow feed and condensate system startup recirculation and layup, a pre-steam generator cleanup line is provided between the outlet (s) of the Amendment No. 12 10.4-12 September 11, 1987
u.
t last feedwater heater (s) and the main condenser. The cleanup loop is designed for 25-50% of the condensate and feedwater flow at the design operating . pressure and temperature. The recirculation piping to the condenser is sized'for 20-25 ft/sec velocity, if the pressure drop is not excessive. :This recirculation loop is typically utilized with two other recirculation loops. One of- these is located downstream of . the gland steam condenser for hotwell recirculation and the - other is located downstream of the deaerator storage tank. Both of these recirculation loops meet the above criteria. .
- 7. . The Emergency ' Feedwater . System connection is located. in the' downcomer feedwater line between the Main Feedwater Isolation Valves, and the steam generator downcomer. nozzle. Emergency feedwater' flow is directed .to the downcomer' nozzle only. A Safety Class 2 check valve located in the main
!feedwater piping upstream of this interface prevents.back flow of emergency
' feedwater to other portions-of the Main Feedwater System.
.8. The system is composed of - three- parallel main feedwater pumps. The ,
feedwater pumps are cross connected during all operations.
- 9. One 'deaerator .and storage tank will be. provided after the low pressure feedwater heaters. The liquid ~ inventory of the deaerator tank, at normal operating : level, is equal to 'at least three and one-half minutes of design feedwater flow. The deareator and connected piping is designed to prevent waterhamer. The deaerator storage tank is positioned to provide adequate NPSH to the feedwater booster pumps during normal and transient
. operation. Transient analyses are performed to assure sati sfactory operation with the deaerator without causing. system or plant trips.
12 )
.- 10.4.7.2.3 Piping, Valves, Equipment and Instrumentation Pioina 1
- 1. The valves, piping and associated supports and restraints of the Main ,
Feedwater System from and including the Main Feedwater Isolation Valves (MFIV) to the steam generator feed nozzles are Seismic Category I and i designed to ASME Code Section III, Class 2 requirements. l l
- 2. ASME Section III, Code Class 2 Main Feedwater System piping is capable of being inspected and tested in accordance with ASME Code Section III and XI.
- 3. All ASME Section III Code Class 2 valves are capable of being periodically inservice tested for exercising and leakage in accordance with ASME Code Section XI, Subsection IWV.
- 4. 'The design of the main feedwater piping and its supports and restraints accommodates the loads arising from the various normal operating and
[ design base,s events as specified in Section 3.9.3.
- 5. Feedwater piping is routed, protected and restrained such that in the case of a postulated rupture that is not eliminated by leak-before-break Amendment No. 12 l 10.4-13 September 11, 1987 1 1
l analysis of a feedwater line or any other system pipeline, single failure '
criteria will not be exceeded with regard to safe shutdown of the plant.
- 6. Each economizer feedwater line is a 20 inch line based on a total flow of 50% of full power flow at normal full power steam generator pressure (1000 psia).
- 7. The downcomer feedwater line is an 8 inch line. This is based on the following:
At 100% power, the downcomer feedwater line shall be sized for a flow of at least 10% of full power flow at normal full power steam generator pressure (1000 psia).
During plant startup, the downcomer feedwater line accommodates all feedwater flow below the temperature of 200'F. !
I Hain Feedwater Isolation Valves and Check Valves 1
- 1. Complete termination of forward feedwater flow is achieved within 5 ,
seconds after receipt of an MSIS. !
- 2. The Main Feedwater Isolation Valves and associated supports and restraints are designed to ASME Section III, Class 2 and will be Seismic Category I.
- 3. The Main Feedwater Isolation Valves are capable of being inservice tested in accordance with ASME Code Section XI, Subsection IWV.
- 4. The Econoinizer and Downcomer Feedwater Line Isolation Valves in each main 12 feedwater line are remotely operated and capable of maintaining tight shutoff under the main feedwater line pressure, temperature and flow resulting from the transient conditions associated with a postulated pipe break in either direction of the valves.
- 5. The Main Feedwater Isolation Valves and their supports and restraints are designed to withstand loads arising from the various normal operating and design bases events. .
- 6. The Main Feedwater Isolation Valves are classified " active" and meet the intent of NUREG-0800.
- 7. Each Main Feed Isolation Valva (MFIV) actuator is physically and electrically independent of the other such that failure of one will not cause the failure of the other.
- 8. The main feedwater lines will meet the provisions of General Design Criteria 54 and 57.
Feedwater Control Valves
- 1. The feedwater control valves have a design pressure / temperature of 2600 psig at 475*F.
Amendment No. 12 10.4-14 September 11, 1987
L
- 2. The Feedwater Control Valves and their supports are designed to withstand loads arising from the various normal operating and design bases events.
- 3. The ' maximum AP for both the Economizer and Downcomer Feedwater Control Valves is 40 psi at normal full power flow and the minimum temperature at which this flow could occur.
Pumol
- 1. Each feedwater pump includes a 5% design margin, i.e., head above the system required pump guarantee point. Excess margin above this is to be minimized.
- 2. Pump head-capacity characteristics continuously slope upwards, with a minimum 10% head rise from design point to shutoff. Two or more pumps operated in parallel have identical characteristic curves and are designed to operate on the steep portion of the curve.
- 3. Two feedwater pumps are driven by adjustable speed steam turbines; these pumps are normally operating. The third pump is an identical standby pump,- driven by a steam turbine and started manually on loss of one of the operating feedwater pumps, permitting the plant to regain 100% power.
Each of the feedwater pumps delivers 50% of the plant related feedwater flow during normal full power operation at normal operating pressure.
Each pump design includes an additional 5% margin to accomodate wear of the pumps. Upon isolation or loss.of one operating feedwater pump, the remaining operating pump is capable of providing a maximum runout flow of.
70% (15%) of the, system rated flow against a steam generator pressure of 1120 phig within 6 seconds after receiving a full flow demand signal from 12 the Feedwater Control System. This provides sufficient flow at the reduced load to prevent a low level trip.
- 4. A constant speed motor driven feedwater pump is utilized for startup and shutdown. Upon loss cf main feedwater and reactor trip, this pump starts automatically and maintains steam generator level.
Instrumentation and Control
~
- 1. The required accuracy of the feedwater temperature measurement devices is 15*F for any calorimetric measurement.
- 2. Feedwater control valves are capable of manual control at all times.
I Insulation
- 1. Non-metallic insulation conforms to NRC Regulatory Guide 1.36. The chloride and fluoride content of the non-metallic insulation are acceptable as shown in Regulatory Guide 1.36. Tests will be made on representative samples of the non-metallic thermal insulation to certify that the maximum chloride and fluoride content are not exceeded. All water used in the fabrication of non-metallic thermal insulation is demineralized or distilled water.
Amendment No. 12 10.4-15 September 11, 1987 i
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- 2. The insulation thickness is selected to minimize the heat load on the containment ventilation ang cooling sEgtem. A thermal transference of not more than 0.14 Btu-br "F -ft of insulated component surface area is used as a design basis for insulation.
10.4.7.3 Safety Evaluation The safety-related portion of the Feedwater System is designed in accordance ,
with the design bases presented in Section 10.4.7.1 (as long as the applicant i conforms with the descriptions and requirements presented in Section 10.4.7.2). Any failure in the non-safety class portions of the Condensate and Feedwater Systems does not prevent safe shutdown of the reactor.
Effects of equipment malfunction on the Reactor Coolant System are presented in Chapter 15.
10.4.7.4 Tests and Inspections 12 ASME Section III Code Class 2 piping is inspected and tested in accordance with ASME Code Section III and XI. ASME Sections III Code Class 2 valves are periodically inservice tested for exercising and leakage in accordance with ASME Code Section XI, Subsection IWV.
See the site-specific SAR for additional test and inspection requirements.
10.4.7.5 Instrumentation Aeolications Feedwater flow control instrumentation measures the feedwater flow rate from the condensate and feedwater system. This flow measurement, transmitted to the feedwater control system, regulates the feedwater flow to the steam generators to meet system demands. Refer to Section 7.7.1.1.4 for a description of the feedwater control system.
10.4.8 STEAM GENERATOR BLOWDOWN SYSTEM 10.4.8.1 Desian Basis The design bases for the Steam Generator Blowdown System are:
- a. Maintain proper steam generator shell side water chemi stry as outlined in Section 10.3.5 by removing non-volatile materials due to condenser tube leaks, primary to secondary tube leaks, and corrosion that would otherwise become more concentrated in the shell side of the steam generators.
- b. Process steam generator blowdown for reuse as condensate.
- c. Enable blowdown concurrent with steam generator tube leak (s) or radioactivity present on the secondary side without release of radioactivity to the environment.
- d. Process a continuous steam generator blowdown rate of 0.2% or 1% of the full power main steam flow.
Amendment No. 12 10.4-16 September 11, 1987
l I l
- e. Continuously sample the radioactivity of the steam generator blowdown.
- f. Isolate the blowdown lines leaving the Containment upon a Containment Isolation Signal , Main Steam Isolation Signal, or Emergency Feedwater Actuation Signal.
10.4.8.2 S_vstem Description j
A continuous high flow blowdown controls the concentration of impurities in the steam generator secondary side water. A general schematic of a typical blowdown system is shown in Figure 10.4.8-1.
Each steam generator is equipped with its own blowdown line with the capability of blowing down the hot leg and/or the economizer regions of the steam generator shell side. The blowdown will be directed into a flash tank :
where the flashed steam is returned to the cycle via the low pressure feedwater heaters. The liquid portion flows to a heat exchanger where it is cooled, and then directed through a blowdown filter where the major portion of the suspended solids are removed. After filtration, the blowdown fluid is processed by blowdown demineralizers and returned to the condenser.
The final design and layout of the Steam Generator Blowdown System is described in the site-specific SAR. The following requirements are to be met to ensure a reliable system.
12
- 1. The Steam Generator Blowdown System is designed to accomodate a continuous blowdown of approximately 1% (172,000 lb/hr) maximum steaming rate (MSR).
- 2. Each steam generator is provided with 2 tubesheet connections, including a 6 inch nozzle for hot leg blowdown, and a 6 inch nozzle for economizer blowdown. The Steam Generator Blowdown System, connected to each steam generator blowdown connection is capable of accommodating a continuous blowdown of approximately 0.5% MSR (86,000 lb/hr).
- 3. Makeup systems are capable of providing secondary makeup water at a rate greater than 172,000 lb/hr. .
4 Steam Generator Blowdown System piping and valves are arranged to allow blowdown from either or both blowdown nozzles.
- 5. The Steam Generator Blowdown Processing System is capable of accepting both a total continuous blowdown rate of 0.2% of each steam generator's MSR (17,200 lb/hr/ generator) while the plant is at power and steam generator chemistry is within normal limits, and a continuous blowdown of up to 1% of each steam generator's MSR (86,000 lb/hr/ generator) while the plant is at power and steam generator chemistry is not within normal limits.
i Amendment No. 12 10.4-17 September 11, 1987
,o
- 6. The thermodynamic conditions at the blowdown nozzles are as follows:
Nozzle Flow Rate Power level Fluid Condition Hot Leg 1% MSR Full Load LATER) psia, (LATER) quality Economizer 1% MSR Full Load LATER) psia, 30-40*F subcool Hot Leg 0.2% MSR No Load LATER) psia, saturated liq.
- 7. Provisions are made to process the continuous steam generator blowdown water to 90% reduced radioactivity levels.
- 8. Blowdown water returned to the steam generator meets the water chemistry requirements outlined in Section 10.3.5.
- 9. The blowdown system piping material is compatible with saturated steam service.
- 10. All components, piping and their supports and restraints associated with steam generator blowdown between the steam generator and the outer most Containment Isolation Valves or Branch Piping Isolation Valves are Seismic Category I and are designed in accordance to ASME Code,Section III, Class 2 requirements.
- 11. Blowdown piping exiting containment consists of Redundant Blowdown Line Isolation Valves in accordance with General Design Criteria 54 and 57 and is isolated by a MSIS, a CI AS , and an Emergency Feedwater Actuation Signal (EFAS).
12
- 12. The S+ .iun Generator Blowdown System piping is used as the means to drain the secondary side of the steam generators. The drain connections are located such that complete steam generator drainage can be accomplished.
- 13. One nitrogen supply connection is provided on either steam generator blowdown line to provide a purge path following steam generator maintenance.
- 14. The steam generators are designed with the capability to achieve the following high capacity blowdown rates and associated thermodynamic conditions at the blowdown nozzles:
Nozzle Flow Rate Power Level Fluid Condition Hot Leg 5.5% MSR Full Load (LATER) psia 17.1% quality Hot Leg 8.6% MSR No Load (LATER) psia 5.6% quality Economizer 8.6% MSR No Load (LATER) psia 5.6% quality
- Note: lowdown piping system with an Conditions equivalent presented assume flow resistance of a f g/0 = 50. The balance of plant design shall provide a system resistance as follows:
l 50<f /0 <60.
Amendment No. 12 10.4-18 September 11, 1987
Maxipum flow capacity assumed an equivalent system resistance of f /D = 50.
The blowdown system is designed for a very high capacity flow (10% MSR) for a short period of time (2 minutes).
- 15. A system is provided to maintain the steam generators in wet layup with the capability to adequately mix, sample, and add chemicals to them.
- 16. In addition to the above described High Capacity Steam Generator Blowdown System, it is recommended that blanked connectors be incorporated in the blowdown and/or main feedwater piping to allow for chemical cleaning of the steam generators should it become necessary in the future.
- 17. Thermal insulation used on the blowdown system inside containment meets the following requirements:
Non-metallic insulation conforms to NRC Regulatory Guide 1.36. The chloride and fluoride content of the non-metallic insulation are 1 acceptable as shown in Regulatory Guide 1.36. Tests will be made on i representative samples of the non-metallic themal insulation to certify that the maximum chloride and fluoride contents are not exceeded. All water used in the fabrication of non-metallic thermal insulation is demineralized or distilled water.
The insulation thickness is selected to minimize the heat load on the containment ventilation and cooling system. It is_1suggest_ep t y t a thermal transference of not more than 0.14 Btu-hr -
- F -ft of 12 insulated component surface area be used as a design basis for insulation.
10.4.8.3 Safet_v Evaluation The Steam Generator Blowdown System is designed to operate manually and on a continuous basis as required to maintain acceptable steam generator secondary side water chemistry. The presence of ASME Section III - Class 2 piping and the system containment isolation function require the system to be designated "duclear Safety Rel ated". , The operation of the system is not required, however, for plant safe shutdown. All blowdown lines which penetrate the Containment are isolated automatically upon containment isolation signal, Main Steam Isolation Signal or Emergency Feedwater Actuation Signal. The portion of the system inside the containment and the portion utilized as containment isolation are designed in accordance with applicable safety class requirements.
10.4.8.4 Tests and Inspections ASME Section III Code Class 2 piping is inspected and tested in accordance with ASME Code Sections III and XI. ASME Sections III Code Class 2 valves are periodically inservice tested for exercising and leakage in accordance with ASME Code Section XI Subsection IWV.
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Amendment No. 12 1 September 11, 1987 10.4-19 !
10.4.8.5 Instrumentation Acolications This system is non safety-related.
10.4.9 EMERGENCY.FEEDWATER SYSTEM 12 (Later - pending completion of EPRI Chapter 5.)
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I j TABLE OF CONTENTS CHAPTER 17 l Section Subject Page No.
17.0 QUALITY ASSURANCE PROGRAM 17.0-1 i
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17.0 OVALITY ASSURANCE PROGRAM The Combustion Engineering Quality Assurance Program is described in topical report CENPD-210A Revision 4, " Quality Assurance Program" dated l12 January, 1987, 1
17.0-1 Amendment flo. 12 September 11, 1987
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