ML19224B286
| ML19224B286 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 07/31/1974 |
| From: | Metropolitan Edison Co |
| To: | Mullinix W NRC/IE |
| References | |
| TM-0300, TM-300, NUDOCS 7906140386 | |
| Download: ML19224B286 (16) | |
Text
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i
- - t TMI DOCUMENTS _
DOCUMENT NO:
7/27-/ 7r
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COPY MADE ON h
OF DOCUMENT PROVIDED BY r
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METROPOLITAN EDISON COMPANY.
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Wilda R. Mullinix, NRC 6
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F INA L SYSTEM DESCRIPTION (Index No. 49)
STEAM GFNERATOR SEC ~NDARY SIDE VENTS AND DRAINS SYSTEM (B&R Dwg. No. 2414, kev. 7)
JEPSEY CENTRAL POWER & LIGHT CG1PANY THREE MILE ISLAND NUCLEM STATION UNIT NO. 2 Issue Date:
July 1974 1r Prepared by:
G. A. Chavez
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Burns and Roe, Inc.
700 Kinderkamack Road
- Oradell, N.
J.
07649 197 026 e
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e TA BLE OF CONTENTS FOR STEAM G E"ERATOR SECONDARY SIDE VENTS AND DRA INS SYSTEM Section Page_
1.0 INTRODUCTION
1 1.1 System Functions 1
1.2 Summary Dcscription of the System 2
1.3 System Design Requirements 4
2.0 DETAILED DESCRIPTION OF SYSTEM 5
2.1 Components 5
2.2 Instruments, Coatrols, Alarms and Protective Devices 6
3.0 PRINCIPA L MODES OF OPERATION 7
3.1 Startup 7
3.2 Normal Operation 7
3.3 Shutdown 8
3.4 Special or Infrequent Operation 9
3.5 Emergency 10 4.0 HAZARDS AND PRECAUTIONS 10
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APPENDIX Title Table No.
S team Genera tor Secondary S ide Dra in Pump 1
Steam Generator Hot Drain Cooler 2
)r 5
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STEAM GENERA'"OR S ECONDARY SIDE VENTS AND DRA INS SYSTEM
1.0 INTRODUCTION
1.1 Svstem Functions The purpose of the drains in the steam generator seco,dary side vents and drains system is to drain or bleed the feedwater from the secondary side of the steam genera tors under reactor generat-ing conditions of refueling shutdown or hot shutdown respectively.
They also provide a means of sampling the secondary side feedwater to measure its quality and the level of radioacti._ty caused by primary to secondary side leakage.
The purpose of the vents in the steam genera tor secondary side vents and drains system is to vent the secondary side to atmos-phere while filling or draining.
They also provide a vent con-nection to the radwaste disposal - gas system to purge the radio-active gases from the secondary side af ter draining the radio-activly contaminated water.
The steam generator secondary side vents and drains system has interfaces with the following systems (Drawing numbers refer to Burns and Roe flow diagrams):
1.
Radwaste Disposal Reactor Coolant - Liquid System (Dwg. No. 2027) 2 Radwaste Disposal - Gas System (Dwg. No. 2028) 3 Secondary Sampling Systam (Dwg. No. 2015)
Ir 4.
Nitrogen for Nuclear and Radwaste System (Dwg. No. 2036) 5.
Steam Generator Chemical C]eaning System (Dwg. No. 2606) 6.
F.W.
Heater Drains (Dwg. No. 2009) 7.
Feed and Condensate (Dwg. No. 2005) 197 029
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l'.'2 Summary Description of the System (Refer to B&R Dwg. No. 2414, Rev.f Each of the two steam genera tors has eight secondary side drain connections and one vent connection that are used in the steam generator secondary side vents and drains system.
The drain connections are located to allow complete draining of the secondary side of the steam generators.
This includes draining the steam annulus between the upper baffle and the shell in the steam section and also the feedwa ter annulus between the lower baffle and the shell in the feedwater section.
Two of the drain connections in the feedwa ter section of each steam generator are used to allow secondary side feedwater s mples to be taken to measure the quality of the secondary side feedwater and the level of radioactivity cause6 by primary coolant (reactor coolant) leaking into the secondary side.
Electric motor operated valves provide remote sampling of the feedwater from the steam generator to the secondary sampling system.
(Refer to Secondary Sampling System Description, Index No. 12).
A vent connection to a tmosphere is provided for venting while draining the secondary side of " clean" water that is within the radioactivity level allowed to be drained into the Susquehanna River af ter dilution as specified by the A tomic Energy Commission regulations 10CFR Part 50, A ppendix "I".
The steam generator I
secondary side d' rain pump discharges the " clean" wa ter to the radwaste disposal reactor coolant - liquid system discharge where continuous radioactivity monitoring is provided.
(Refer to the Radwaste Disposal Reactor Coolant Liquid System Description, Index No. 21) 197 030
A flexible nitrogen connection to the main steam line vents is provided to pressurize the secondary side in order to drain it when the radioactivity is above the allowable " clean" water level.
(Refer to the Nitrogen for Nuclear and Radvaste f item Description, Index No. 30).
The secondary side drain heauer discharge line has a spool piece to change from the steam generator secondary side drain pump suction to the reactor coolant drain header.
(Refer to the Radwaste Disposal Reactor Coolant-Liquid System Description, Index No. 21).
A flexible nitrogen connection to the secondary side common drain discharge line and a flexible radwaste gas disposal connection to the steam generator vent line are provided to purge the steam generator of radioactive gas af ter draining the secondary side of all radioactive liquid.
(Refer to the Radwaste Disposal -
Gas System, Index No. 22).
One steam genera tor hot drain cooler is provided to cool feedwater drained from either steam generator while at their full design temperature and pressure.
The feedwater is cooled by chromate treated demineralized cooling wa ter (Refer to In termedia te Closed cooling wa ter System, Index No. 23).
The secondary side steam generator hot drain cooler discharges the cooled feedwater through a pressure reducing orifice to the Heater Drain Tank (Refer to F.W. Heater Drains, Index No. 7).
/r The flexible nitrogen connection to the main steam line vents is used for pressure testing to determine the location of leaking tubes, during chemicau ning of the steam genera tors (Refer to the Steam Generator Chemical Cleaning System, Index No. 60), and for dry layup of the steam genera tor.
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1.' 3 System Desian Requirements The steam generator secondary side vents and drains system is a nuclear N-2 type system except the steam generator secondary side drain pump and the steam genera tor hot drain cooler in-cluding their immediate suction and discharge piping and the piping outside the reactor building downstream of the is ola tion valve which are of conventional design.
All system piping is d e s igne d, fabricated, inspected and erected in accordance with their respective codes.
The applicable code for nuclear piping of 2 inches diameter and smaller is ASME Nuclear Power Plant Components section III, the code for nuclear piping larger than 2 inches diameter is ANSI B31.7 Nuclear Power Piping and the code for conventional piping is ANSI B31.1.0 Power Piping.
The system seismic design classification is Class I for nuclear N-2 type components and Class II for conventional components.
Each steam generator is able to be sampled and drained independently since the secondary side of one steam generator can be radio-actively contaminated because of a primary to secondary leak while the secondary side of the other steam generator may not be contaminated.
A nitrogen connection to each main steam line vent is provided to pressurice the secondary side.
A nitrogen connection to the common drain header discharge line is provided to purge the secondary side bf radioactive gases af ter draining the radio-actively contaminated liquid.
Connections to the radwaste disposal - gas system and the 3
7 radwaste disposal reactor coolant - liquid system are provided to treat radioactive gas and liquid from the secondary side of l
the steam generators.
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'A vent connection from each steam genera tor to a tmosphere and a common drain connection to the stecm generator secondary side drain pump are installed to drain the secondary side of " clean" water.
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Either steam generator can be drained to the hot drain cooler to provide the ability to lower their water level while at full design temperature and pressure.
The hot drain capability is used, in conjunction with the Feed and Condensate System (Index No. 4A) during unit shutdown, to correct chemical upset conditions and to maintain minimum feedwater flow to prevent feedwater cooldown.
2.0 DETAI 2D DESCRIPTION OF SYSTEM 2.1 Components 2.1.1 Steam Generator Secondarv Side Drain Pump SV-P-1 The steam generator secondary side drain pump (see Table 1) is a horizontal, centrifugc2 pump with a capacity of 125 gpm at a total discharge head of 115 feet.
The pump takes suction from the steam generators secondary side common drain header and discharges to the mechanical draft cooling tower normal discharge.
The pump is driven by a 7-1/2 hp induction motor.
Pump control and indication is local.
The pump is powered frcm Bus 2-32A.
The pump is located 'n the Reactor Building at elevation 282'-6".
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2.1.2 Steam Generator Hot Drain Cooler SV-C-1 The steam generator hot drain cooler (see Table 2) cools the secondary side steam generator water for passage from the Reactor Building to the Heater Drain Tank in the Turbine Build-2 ing by heat tr< n :#=r to the intermediate Closed Cooling Water System.
The cooler is a single pass shell and tube type with 197 033
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e the steam generator secer2;&y side feedwater on the shell side 1
and the Intermediate C.osed Cooling water on the tube side.
The cooler is designed in accordance with the ASME Code,Section VIII, TE:4A "C".
Tubes are seal welded into the tube sheet.
The cooler is located in the Reactor Building at eleva tion 2 82 '-6 ".
2.1.3 Maior Svstem Valves Steam Generator Secondarv Side Samplina Valves SV-V10A,10 B,11A, llB Two sampling valves are provided on the secondary side of each steam generator.
Each valve is Class N-2, motor operated inch globe valve designed for 1050 psig and 600 F.
Remote manual operation of the valves is available from TMI No. 2 nuclear sampling panel No. 329 in the nuclear sampling room located in the TMI No. 1 plant.
Power is supplied to the valve motor operators from MCC 2-32B and 2-42B for SV-lCA/llA and SV-10B/llB respec-tively.
Valve position indicating lights for each valve are provided on the Turbine Auxiliaries Monitoring Panel 17.
2.2 Instruments, Controls, Alarms and Protective Devices 2.2.1 Instruments and Centrols The only instrumentation and controls associated with the steam generator secondary side vents and drains system are the remo;te hand switches SV-FHS-3774, 3775, 3776 and 3777 to operate the ir secondary side sampling valves SV-v10A, 10B, llA and llB respectively.
The hand switches are on the TMI No. 2 sampling panel No. 329 located in the nuclear sampling room in TMI No. 1 plant.
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'T h e tube side is provided with a safety relief valve SV-R2 set at (later) with a 1" inlet and a 2" discharge which is piped to the Reactor Building Sump.
3.0
. PRINCIPAL MODES OF OP ERA TION 3.1 Startup The steam generator secondary side vents are not used during plant startup but the secondary side drains may be used.
When the turbine bypass valves are closed during hea tup. - (refer to the Main and Reheat Steam System Description, Index No. 1) the feeduater control valves will close (refer to
' Feedwater and Condensate System Description, Index No. 4A ).
The feedwater in tre feedwater lines between the feedwater control valves and the steam ge..erators will begin to cool.
To prevent the feedwater from cooling below the minimum tempera ture allowed to enter the steam generator, the secondary side dr,in valves are opened and lined up to the steam generator hot dra in cooler.
This will decrease the level in the steam generator and the feedwater control valves will open.
This operation is illustrated in Figure LA-7 of Babcock and Wilcox Specification for S team Generator No. CS(F)-3-92/NSS-6/1070.
3.2 Normal Operation During normal plant operation the steam generator secondary side vents and Erains system is not used for venting or draining the secondary side of the steam generators.
The secondary side sampling valves are used to periodically take samples of the secondary side feedwater to rueasure the quality and level of radioactivity.
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3. 3' Shutdown After the plant is shut down, the secondary side of the steam genera tors may be drained by the Radwaste Disposal Reactor Coolant-Liquid System af ter being cooled to at least 200 F
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and af ter taking samples of the secondary side feedwater to m easure the radioactivity level of each steam generator.
If the radiocctivity level of the secondary side feedwater of a steam generator is within the " clean" wa ter level as described in section 1.2 of the system description, the secondary side is drained to the radwaste disposal reactor coolant-lit;uid sys tem discharge.
The steam generator vent to atmosphere is first opened, the drain valves are opened and the steam generator secondary side drain pump is put into operation.
If the radioactivity level of the secondary side feedwater of a steam generator is above the " clean" wa ter level, the secondary side is drained to tne reactor coolant drain header for treat-ment.
(Refer to the Radwaste Disposal Reactor Coolant - Liquid System Description, Index No. 21).
The secondary side of the steam genera tor is first pressurized with c itrogen through the main steam line vent, the spool piece in the secondary side common drain line is connected to the reactor coolant drain header and then the drain valves are opened.
A f ter the second-1r ary side is drained of water, it is purged of radioactive gases by disconnecting the nitrogen supply to the vent connection, connect the vent to the radwaste disposal - gas system and then the nitrogen supply is connected to the secondary side common drain line discharge header.
The nitrogen is used to purge the I
radioactive gases from the secondary side of the steam generator I
to the radwaste disposal - gas system.
1 197 036
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For a chemical upset condition in the steam generator, the full water inventory of the steam genera tor can be changed within two hours with the plant in a hot shutdown condition.
Af ter the plant is in hot shutdown, the secondary side fee? water
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of the steam aenernenrs may ha changed by maintaining steam generator water level and bleeding and feeding feedwater to bring the chemistry into spec.
The cooling water is first va lved to the steam generator hot drain cooler before valving either steam generator drains to the hot drain cooler.
Two orifices are provided in the hot drain cooler discharge to monitor flow and to reduce pressure into the Heater Drair Tank.
3.4 Special or Infrecuent operation
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3.4.1 Steam Generator Chemical Cleaninc The steam generator secondary side vents and drains system is used during the chemical cu aning opera tion of the steam generators.
The steam genera tor secondary side drain pump ( S V-P-1) may be operated at a temperature of 200 F with NPSH of 12 feet.
This requires that the 5 psig nitrogen blanket be maintained through-out this operation.
Refer to Babcock and Wilcox Pressurized Water Reactor Technoloav, Volume 2 and Babcock, Uilcox Once-Throuch Steam Generator Instruction Manual No. 620-0006, and Steam Generator Chemical Cleaning System (System Description No. 60).
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3.4.2 Steam Generator Tube Leak Detection The steam genera +.or secondary side vents and drains system
.s used during the tube leak detection operation of the steam generators.
- Refer to Babcock and Wilcox Pressurized Wa ter Reactor Technoloav, Volume 2 and Babcock and Wilcox Once Throuch Steam Generatcr Instruction Manual No. 620-0006.
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197 037
m.
3 '. 4. 3 Ster
.Se 3 tor Wet and Drv Layup 5
1he steam generator secondary side vents and drains system is
,ed durii., wet and dry layup opera tions of the steam generator.
Refer to Babcock and Wilcox Once-Throuch steam Genera tor Ins truction Manua l, No. 620-0006.
3.5 emeroency There are no emergency opera tions or procedures associated with the steam generator secondary side vents and drains system.
4 ~. 0 HA ZA RDS A ND PRECAUTIONS Only one steam generator a t a time is to be drained.
This will prevent radioactive contamination of one steam generator from entering the other which may not be contamina ted from primary to secondary leakage.
The steam generator hot drain cooler cooling water flow should first be established in the cooler tube side prior to draining hot, pressurized steam generator feedwa ter to the shell side.
This will prevent excessive tube cide pressurization and cafety relief valve actuation.
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TA BLE 1 STEAM GENERATOR S ECONDA RY S ID E DRA IN PUMP Pump Deta ils Identification SV-P-1 Number Installed 1
Manufacturer Crane-Deming Model No.
3062 Type Process Rated Speed, RPM 3,500 Rated Capacity, GPM 125 Rated Total Dynamic Heat, ft. 115 UPSH required at rated flow, ft.
5 Casing Design Pressure,psig 100 Design Tempera ture, F
70-100 Lubricant / Coolant Oil /Im Min. Flow Requirements, GPM 3
Motor Details Manufacturer Westinghouse Type Induction Enclosure Open Rated Horsepower, HP 7
Speed, RPM 3,500 Lubricant / Coolant Oil /A ir Power Requirements 460V, 3$, 60 Hz, 9.9 amps (full load)
Power Source MCC 2-3 2A
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TA BLE 1 (Continued),
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STEAM GENERATOR SECONDA RY SIDE DRAIN PUMP Cla s s ifica tion Level Code C
Quality control 4
Seismic II Cleanliness D
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TA B LE 2 STEAM GENERATOR HOT DPfTN COOLER Iden tifica tion SV-C-1
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Number Installed 1
Manufacturer Whitlock Model No.
12-3-174 Cleanliness Factor, %
80 Heat Transfer, Btu /hr 2.37 x 10 Tube Side Flow, GPM 461 Source I.C.C.W.
Design Pressure, psig 150 Design Tempera ture, F
600 Ma t er ia l Carbon Steel Pressure Dfop, psi 4
Shell Side Flow, GPM 120 Source S/G Secondary Side Design Pressure, psig 1050 o
Design Tempera ture, F
600 Ma teria l Carbon Steel Pressure Drop, psi 2
Ir Classification Level Coce C.
Quality Control 4
Seismic II
,4 Cleanliness D
197 041