ML20196K523

Rev 6 to Div Sys Description for Dewatering Sys for Defueling Canisters

ML20196K523
Person / Time
Site:	Three Mile Island
Issue date:	06/30/1988
From:	Matthew Smith GENERAL PUBLIC UTILITIES CORP.
To:
Shared Package
ML20196K509	List: ML20196K506 ML20196K523
References
SD-3525-014, SD-3525-014-R06, SD-3525-14, SD-3525-14-R6, NUDOCS 8807070012
Download: ML20196K523 (22)

Text

l Nu;3 lear SD 3ses-oi4 ney e ISSUE DATE JJne 1988 G its D NSR O HliS l

DIVISION SYSTEM DESCRIPTION FOR Dewatering- System for Defueling Canisters L, COG ENG hio. 1 4D DATE #46 /6'e RTR CO MM /? DATE 16/88 COG ENG MG v - v 24 C ATE S f8 v

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• 22 DOCUMENT PAGE 1 OF

No.

Nuclear 3525-014

" Page 2 of 22 System Description for Dewatering System for Defueling Canisters Approval Date Rev. *

SUMMARY

OF CHANGE ,

1 Added Section 3.7.3'; Added Ref, 23-20, changed Ref. / , y clarified Ref. 2, 5, and 22 (Sect.1.2); Added V016A/B and bypass spool piece para. , updated relief valve para. ,

and venting to SDS offgas, changed "flapper" to "paddle" in reference to sightglass (Sect.1.3.1); Deleted breathc r vent filter, updated pump and crane info. (Sect.1.3.2);

Changed pressures '($ect.1.4); Added Sentence on locatior of controls (Sect.1.5 and 1.6.1); Changed "reachrods" to "extension stems," added sentence on V047 (Sect. 1.5 and 1.6.2); Changed HS-9A/B to HI '^ /B (Sect.1.6.1 and 3.3.5); Added "after dewatering ana also prior to shipping" (Sect.1.6.4); Clarified venting in Item 1 (Sect. 1.7); Changed cover gas pressure (Sect. 2.1 and 3.3.3); Added sentence for R-3 and "above the bottom of the tank" (Sect. 2.2); Added "to the holdup tank (T-1),

which in turn is vented" (Sect. 2.3); Added para, on dewatering last canister, changed initial pressure (Sect. 3.3.2.1); Changed initial pressure (Sect. 3.3.2.2 Changed V004A/B to V016A/B (Sect. 3.3.6): Deleted valve V026 (Sect. 3.4); Added sentence for transfer and drain lines (Sect. 3.5); Changed "flapper" to "paddle" (Sect.

3.7.1); Changed "15" to "13" and "SDS offgas system" to l

"holdup item 6 Sect. (tank" (Sect.

4.1, 4.2, and 3 7.2);

4.3); Added"color Changed Section coded"3.7.1; De'eted i

to "different sizes" and "approximately four" to "several", deleted sentence on location (Sect. 7.0).

2 Added "V002A and V002B", sentence on filter pressure A

' drop, jib crane information, information on tank effluent concentration and dilution, "V041", the design l

pressure and temperature, deleted information on argon manifold meeting CGA standards, changed "recirculatien" l

I to "backflush" (Sect.1.3.1); Added "Division I, Part UU (lethal) (1983)" (Seet. 1.3.2); Added "V002A and V002B",

"V041", and "V017" (Sect. 1.6.1); Deleted phrase about V04, having a standard handle (Sect.1.5 and 1.6.2);

Added "V0'7", changed "inside" to "at" (Sect. 1.6.4);

Added fifth system interface (Sect.1.7); Added "V002A 2 and V002B" (Sect. 3.3.2.1, 3.3.2.2, 3.3.6); Added filter E

canister di fferential pressure information and mininum weight loss (Sect. 2.1); Added effluent concentration

[ information (Sect. 3.3.5); Revised the second sentence a

2 (Sect. 3.5); Changed leak criteria (Sect. 3.3.6);

M Deleted sentence on opening V025 to backflush, added ,

's sentence on how backflush line is filled (Sect. 3.7.1);

Revised rewetting method (Sect. 3.7.3); Changed "six" (i to "five", moved "and" (Sect. 4.1) .

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Nuolear 3525-014 Title Page 3 of 22 System Description for Dewatering System for Defueling Canisterr Rev.

SUMMARY

OF CHANGE Approval Da te 3 Added information about flow indicator on sampling return .##

line (Sect. 1.3.1 and 1.6.4); Revised Section 5.0 to delete forthcoming information.

4 Revised pressurization sequence for dewatering a filter 4*

canister, increased maximum dewatering pressure, revised dewatering end point criteria.

5 Reformated Section 1.2 by deleting Items 23-26 and incor- ##M 8/87 parating into Item 2, a through e; deleted Item 27 through 30 and incorporated into Item 6, a through e; added Miscellaneous Waste Holdup Tank as a transfer path for DS effluent; added check valves V063A and V063B; added ability to backflush using water and/or argon; deleted reference to ion chambers used to obtain curie estimates for dewatered canisters; increased cover gas pressure to 13-15 psig; increased dewatering gas pressur(

to 40 psig; revised canister pressure check to indicate that canister is monitored for 10 minutes after removing relief valves; added flexibility to rewet filter media using a baci fill from DS-T-1; added Safety Evaluation Report 4350-3256-85-1, "Canister Handling and Preparatior for Shipment," as a reference.

Added the ability to utilize either a 0.5 micron or 16 g 6/88 6

micron (nominal) filter in the DS-F-1 position; revised  !

I maximum pressure drop across DS-F-1 to 55 psig; added high motor temperature trip to HIS-9A and HIS-98; revisec backflush of canister to reflect ability to backflush knockout and fuel canisters at pressure up to 40 psig; i

I l indicated ability for local grab samples downstream of V031A(B); revised rating of platform jib crane to 500 lbs; added ability to use SDS Vacuum Outgassing and l

Drying System for canister gas samples and for final 1 dewatering; revised dewatered weight of a filter to be greater than 199 lbs to agree with 25% void volume; added statement of commitments to disinfect filter canisters and of current procedure to dewater filter j canisters ir. the DS-F-1 position.

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3525-014 TABLE OF CONTENTS Section Page 1.0 DESIGN DESCRIPTION 6.0 1.1 Summary 6.0 1.2 References 6.0 1.3 Detailed System Description 7.0 1.4 System Performance Characteristics 11.0 1.5 System Arrangement 12.0 1.6 Instrumentation and Controls 12.0 1.7 System Interfaces 14.0 2.0 SYSTEM, LIMITATIONS, SETPOINTS, AND PRECAUTIONS 15.0 2.1 Limitations 15.0 2.2 Setpoints 15.0 2.3 Precautions 15.0 3.0 OPERATIONS 16.0 3.1 Initial Fill 16.0 3.2 Startup 16.0 3.3 Normal Operations 16.0 3.4 Shutdown 19.0 3.5 Drainino 19.0 3.6 Refilling 19.0 3.7 Infrequent Operations 19.0 4.0 CASUALTY EVENTS AND RECOVERY PROCEDURES 20.0 4.1 Casualty Events 20.0 4.2 Design Features to Mitigate Effects of Casualty Events 21.0 4.3 Recovery Procedures 21.0 5.0 MAINTENANCE 22.0 Rev. 6/0045P i

3525-014 i TABLE OF CONTENTS (Cont'd)

Section Page 6.0 TESTING 22.0 6.1 Hydrostatic Testing 22.0 6.2 Instrument Testing 22.0 6.3 Periodic Testing 22.0 7.0 HUMAN FACTORS 22.0 i

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3525-014 1.0 D_ESIGN DESCRIPTION 1.1 Summary The Dewatering System is a recovery system which removes and filters the water from submerged defueling canisters and provides a transfer path to the Defueling Hater Cleanup System (DHCS) or the

-Miscellaneous Haste Holdup Tank (HDL-T-2) for future processing.

The Dewatering System also provides the cover gas for canister shipping.

The water is removed from the defueling canisters to: 1) reduce the weight of the canisters for shipping, and 2) prevent the hydrogen / oxygen catalysts from being submerged. The argon cover gas is provided to: 1) reduce water intrusion when the canister is in the water, 2) reduce air intrusion when the canister is out of the water, and 3) reduce the pyrophoricity potential of the debris within the canister.

1.2 References

1. Bechtel Drawing 15737-2-M74-DS01, Piping and Instrument Diagram - Dewatering System.

2. Bechtel Piping Isometrics.

a. 2-P60-0501 - Dewatering System, Fuel Handling Building E1. 347'-6".

b. 2-P60-DS02 - Dewatering System, Dewatering Canister Inlet and Outlet Piping.

c. 2-P60-DS03 - Dewatering System, Off-Gas and Sample Piping.

d. 2-P60-DSO4 - Dewatering System, Tank DS-T-1 Connections and Miscellaneous Details.

, e. 2-P60-DS05 - Dewatering System, Argon Supply Piping, Fuel l Handling Building Fuel Pool 'A' l

3. Bechtel Drawing 15737-2-P0A-6401, General Arrangement-Fuel Handling Building Plan E1. 347'-6".

4. Safety Evaluation Report for Defueling the THI-2 Reactor Vessel, Document No. 15737-2-G07-107.

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5. Bechtel Drawing 15737-2-COP-6201, Dewatering System Platform.

6. Bechtel Pipe Supports Drawings:

a. 2-C64-DS01 - Pipe Supports for Isometric 15737-2-P60-DS01.

b. 2-C64-DS02 - Pipe Supports for Isometric 15737-2-P60-DS02.

c. 2-C64-DS03 - Pipe Supports for Isometric 15737-2-P60-DS03.

d. 2-C64-DSO4 - Pipe Supports for Isometric 15737-2-P60-DS04.

t. 2-C64-DS05 - Pipe Supports for Isometric 15737-2-P60-DS05.

Rev. 6/0045P

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3525-014

7. GPU Nuclear Orawing 2R-950-21-001, P&ID Composite-Submerged Demineralizer System.

8. Instrument Index, Document No. 15737-2-J16-001.

9. Design Engineering Valve List, Document No. 15737-2-P16-001.

10. Mechanical Equipment List, Document No. 15737-2-M16-001.

11. Standard for Piping Line Specifications, Document No.

15737-2-P-001.

12. Piping Line Index, Document No. 15737-2-P-002.

13. Intermediate Evaluation of Special Safety Issues Associated with Handling the TMI-2 Core Debris, prepared by Rockwell Hanford Operations, Document No. SD-HH-TA-005.

14. Bechtel Drawing 15737-2-J78-DS01, Level Setting Diagram.

15. Bechtel Drawing 15737-2-J74-DS01, Instrument Installation Detail.

16. Bechtel Drawing 15737-2-J74-DS02, Instrument Installation Detail.

17. Bechtel Drawing 15737-2-E76-OS01, Pump Schematic Diagram.

18. Bechtel Drawing 15737-2-J77-OS01, Pump Logic Diagram.

19. Bechtel Drawing 15737-2-EOR-6401, Fuel Handling Building El.

347'-6" Electrical Physical Drawing.

20. Bechtel Drawing 15737-2-E21-010, Single Line Diagram.

i 21. ECA 3221-84-0111, Standby Reactor Coolant Pressure Control (SPC) Surge Tank Removal.

l 22. ECA 3255-84-0087, Dewatering System Design.

l l 23. ECA 3255-87-0445, Dewatering System Modifications.

24. Safety Evaluation Report for Canister Handling and Preparation for Shipment, Document Number 4350-3256-85-1.

I 1.3 Detailed System Description 1.3.1 The Dewatering System (DS) is designed to remove and filter water from the three (3) types of defueling canisters - fuel, knockout, and filter canisters. The water removco from the canisters is transferred to the OHCS for processing through the OHCS ion exchanger K-2 or transferred to the Miscellaneous Waste Holdup Tank (HDL-T-2) for future processing.

Rev. 6/004"-

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3525-014 As discussed in Reference 24, removal of the water in the defueling canisters will reduce the weight of the canisters to meet shipping requirements and will ensure that the catalysts remain effective. Argon cover gas, at approximately 2 atmospheres absolute, prevents air or water intrusion. When a canister is submerged, water intrusion may raise the water level in the canister above the catalysts, making them inoperable. When the canister is out of the water, air intrusion increases the pyrophoricity potential of the defueling debris within the canister. For more information on catalysts, pyrophoricity and the use of argon within the defueling canisters refer to Reference 13.

High pressure argon from cylinders is supplied through a manifold which regulates the pressure to approximately 45 psig. The argon supply line then branches to provide a source of gas for two (2) dewatering and gas covering trains. A pressure regulator for each train V002A and V0028, (PCV-1A and PCV-18) is supplied so that dewatering one canister while covering a second canister may be accomplished simultaneously and independently. An ASME Section VIII Code relief valve (R-3) prevents the argon supply lines and the defueling canisters from being pressurized above 110 psig. The canisters are ASME Section VIII Code vessels and, therefore, must be protected against overpressurization as stated in part UG-125 of the Code. R-3 is provided to meet this requirement. R-1A and R-18. located downstream of V002A and V0028 (PCV-1A and PCV-18), are set to relieve at 55 psig.

This set pressure prevents the possibility of a 60 psi pressure drop across the filter media in a filter canister which could damage the media.

Valves (V004A and V004% shut off the argon flow to the canisters. Check valvet (V063A and V063B) installed downstream of V004A and V004B prevent backflow of contaminated 11guld into argon nanifold. The pressure indicators (PI-2A and PI-28) ara iocat.5 Jpstream of these valves so that the pres'are may be adjusted to the correct setti.,g before allowing argon to flow into the canisters.

A flow indicator for each train (FI-3A and FI-38) indicates when gas flow into the canisters has stopped; this signals the need to increase the pressure to continue dewatering or that the effluent path is blocked.

Pressure indicators (PI-12A and PI-128) are only used to measure cover gas pressure in the defueling canisters immediately following dewatering and just prior to canister shipping. V016A and V0168 are immediately upstream of the indicator takeoffs. V016A or V0168 is closed when the canister pressure is checked prior to shipping. This way the argon supply line through the control manifold to V016A or V0168 is not pressured by the canister and effects on canister pressure should be minimized.

Rev. 6/0045P

3525-014 Hoses with Hansen quick disconnect couplings connect the argon supply. lines and effluent paths to the defueling canisters

'with the aid of. remote handling tools (furnished under the canister task). A jib crane is mounted on the DS platform to handle DS tools and assist in maintenance and repair activities. 'The jib crane meets ANSI 830.11-1980 and THI-2 Lifting and Handling Program requirements. Sight flow indicators with internal paddles-(FG-5A and FG-50) are located in the effluent lines. Gas bubbles in a sight flow indicator indicate that the canister'is dewatered to the extent possible. If the internal paddle is motionless, it is an indication that either the canister drain is clogged or that the carister is at an equilibrium state. The argon gas that enters the effluent lines is vented to the OS holdup tank (DS-T-1) via automatic vent valves (V011A and V0118).

The effluent water is filtered through a filter canister (F-1), which has either a 0.5 or a 16 micron nominal rating, and stored in the holdup tank (T-1). When the system is in the recirculation mode (see Section 3.3.5), the differential pressure across the filter, F-1, for all practical purposes can be read from pressure indicator, PI-4, since the holdup tank, T-1, is under a slight negative pressure (i.e. , less than 12 inches of water). When the pressure drop across the filter canister, F-1, reaches approximately 55 psi, the filter l

canister is fully loaded and rust be replaced. The tank is vented to the Submerged Demineralizer System (SDS) off-gas filter and has a overfill line to the spent fuel pool which prevents water from entering the SDS off-gas vent piping. A submerged inlet, with isolation valves V018 and V059, has been provided on the tank to allow the addition of borated pool water into the tank. Borated pool water may be needed in the tank for the backflushing operation if the amount of water in the tank Trom dewatering is not sufficient, and for diluting the effluent in the tank. A bubbler indicates the water level in the tank.

[ The pumps'(P-1A and P-18) are submersible horizontal centrifugal pumps. Because the pumps are located underwater where maintenance and repair are impractical, two (2) 1007.

capacity pumps are provided. The pumps are manually controlled by HIS-9A and HIS-98 with an interlock that trips the pumps on low level in the tank, T-1, and on high motor temperatures. The pumps transfer the water in the holdup tank l to the DHCS for processing, or to the Miscellaneous Haste Holdup Tank (HOL-T-2).

The transfer pumps have a recirculation line back to the filter, F-1, with a sample line that runs to OHCS Sample Box No. 1. This provides the ability to further filter the effluent, and the opportunity to sample the effluent before transferring it to the OHCS ion exchanger or to the

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rp 3525-014-

'Miscellaneuus Waste Holdup. Tank (WDL-T-2). The concentration of the effluent from the tank should below 0.84 uC1/cc, Cs-137 prior to transferring the effluent to the OHCS lon exchanger.

Flow indicator, FI-16, on the return line from the sample box provides confirmation of flow in tha sample line.and indicates the rate of flow.

The backflush line provides'the ability to reverse the flow of argon and/or water back into a defueling canister to clear a drain screen that has become clogged (i.e., to backflush).

For water, the backflush line is filled from valves V005A and V005B to valve V043 by opening valve V022. Valve V022 is then closed and the line is pressurized with argon by opening the supply line with valve V043 which simultaneously closes the vent line. The argon pressure is controlled by pressure regulator V041 (PCV-10) and measured by pressure indicator PI-14. The three-way plug valve, V005A or V005B, is positioned so that the appropriate canister is backflushed.

The volume of backflush water is limited to the amount of

. water in the pipe from valve V043 to valves V005A and V005B, which is less than five (5) gallons. For modified backflush using argon, the argon pressure is controlled by pressure regulator V041 and monitored by pressure indicator PI-14.

When the pressure has been adjusted, the backflush line is pressurized by opening V043 which simultaneously closes the vent line. The three-way plug valve, V005A and V005B, is r positioned so that the appropriate canister is backflushed.

The operating pressure for either backflush is controlled by the operator and maintained below 10 psig for filter canisters and below 40 psig for fuel and knockout canisters. The relief valve, R-2, is normally set at 10 psig to protect the filter media in a filter canister which can be damaged if the .

differential pressure during reverse flow exceeds 10 psig.

When backflushing a fuel or knockout canister, the relief valve, R-2, is defeated to allow an increased backflush pressure not to exceed 40 psig.

The argon supply lines into the canisters have a branch which' provides a flow path for gas and water which exits the canister during backflushing. This flow path is opened with the three-way plug valve, V006A or V0068, which also isolates the argon supply line. An automatic vent valve, V008, vents gas from backflushing to the holdup tank, T-1. Water from backflushing is routed back to the filter, F-1, and into the holdup tank, T-1, for transfer to the DHCS.

A connection consisting of an isolation valve and a Hansen quick disconnect coupling is provided on each effluent line and the vent line to the SDS off-gas system. These connections are provided so that the system can be flushed to reduce dose rates in the system. In addition, the connections downstream of V031A and V0318 may be utilized for local grab Rev. 6/0045P

3525-014 samples during canister dewatering. Bypass spool pieces are provided to connect canister inlet and outlet lines without using a canister. These bypass spool pieces facilitate flushing, provide a. storage location for connection tools, and enable the last defueling canister to be dewatered directly to the holdup tank. Water which meets Technical Specification requirements shall be used for flushing.

All DS piping is designed in accordance with ANSI 831.1, 1983 Power Piping.

The design pressure and temperature of the DS piping is 50 psig at 100'F.

1.3.2 Major System Components F-1 Filter Type: Defueling Canister with Sintered Metal Pleated Filter Mfr/Model: B&W and Pall Rating: 0.5 or 16 micron nominal Code: ASME VIII, Division I, Part UH (lethal)(1983)

P-1A and P-1B Transfer Pumps Type: Submersible Horizontal Centrifugal (Canned Motor)

Mfr/Model: Lawrence Pump and Engine Co./AIMD Material: Stainless Steel Rating: 60 gpm at 100' TDH T-1 Holdup Tank (Previously used as SPC-T-3)

Materials: Stainless Steel Dimensions: 54.17" 0.0., 166.55" High Rating: 2735 psig, 300*F Volume: 900 gallons Code: ASME III, Class 2 A-1 Crane Type: Jib Mf-/Model: Air Technical Industries /JC-22020 Rating: 500 pounds Code: ANSI B30.11-1980 1.4 System Performance Characteristics The dewatering and covering operations are performed at the i following argon supply pressures:

1. Cover gas pressure 13-15 psig

2. Dewatering gas pressure

! a. Filter canister 3-40 psig l b. Knockout canister 3-40 psig

( c. Fuel canister 3-40 psig

3. Argon supply manifold pressure 45 psig l

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3525-014

-Backflush pressure 4 .'

a. Filter canister <10 psig

b. Knockout canister <40 psig

c. Fuel canister <40 psig The transfer pumps operate at 100 feet TDH at 60 gpm.

1.5. System Arrangement The DS platform is located at the northeast end of Spent Fuel Pool "A" and the top of the platform is at elevation 331'-3" (see Reference 3). The platform is designed to support the activities required to handle two (2) defueling canisters during dewatering and gas covering. Instrumentation and controls for the argon supply are located at a D3 control area on 347'-6" in the vicinity of the northeast end of Spent Fuel Pool "A". Instrumentation and controls for pumping operations are located at the west end of the intermediate DS platform at elevation 341'-3" in the northeast end of Spent Fuel Pool "A".

The system equipment is located underwater in this area except for: 1) the argon manifold and supply lines up through valves V016A and V0168, 2) portions of the DHCS tie-in, 3) the sight flow indicators (FG-5A and FG-58), and 4) the majority of valves. The majority of valves are located above the water level but below the DS platform. All valves below the platform are manually operated by extension stems. Piping that is not underwater and contains radioactive fluid will be shielded to limit dose rates to 2.5 mrem /hr.

The platform consists of removable sections so that the valves and equipment are accessible for maintenance and repair.

1.6 Instrumentation and Controls 1.6.1 Controls The controls for the argon supply are located on elevation 347'-6" in the vicinity of the northeast end of Spent Fuel Pool "A" at a DS control area. Instrumentation and controls for pumping operations are located a: the westend of the intermediate DS platform at elevatior '-3" in the northeast end of Spent Fuel Pool "A". All oper ons are manual, except for an interlock with the holdup tank level indicating switch, LIS-8, that trips the pumps, P-1A and P-18.

The argon supply to the dewatering canisters is controlled by the on-off valves, V001A and V0018. The argon pressure to the dewatering canisters is regulated by pressure regulators V002A and V0028 (PCV-1 A and PCV-18), and the flow is controlled by valves V004A and V004B. The argon prossure for backflushing is regulated by pressure regulator V041 (PCV-10). The argon supply to the backflush line is controlled by the three-way plug valve V043.

Rev. 6/0045P l

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3525-014 The transfer pumps are manually operated by HIS-9A and HIS-98

. with an interlock that trips the pumps on low level in the tank, T-1. The air supply pressure for the holdup tank water

-level measuring device is regulated by the pressure regulator V017 (PICV-6), and the air flow for the bubbler is regulated by the purge rotameter, FICV-7, 1.6.2 Valves

.All valves are manually operated. Valves below the DS platform are operated by extension stems from the OS platform.

1.6.3 Power 480V, three (3) phase starters are located at the DHCS motor control center, DHCS MCC 2-32C, for the transfer pumps P-1A and P-18. 120 VAC power is available for lights and remote cameras.

1.6.4 Monitoring The argon supply pressure and flow to the dewatering canisters are monitored by pressure indicators, PI-2A and PI-28, and flow indicators, FI-3A and FI-38. The canister pressure, after dewatering and also prior to shipping, is monitored by the pressure indicators PI-12A and PI-128.

The argon pressure for backflushing is monitored by pressure indicator PI-14.

Pressure regulator V017 (PICV-6) and purge rotameter FICV-7 monitor the pressure and flow of the instrument air for the level indicator (bubbler).

Level indicating switch, LIS-8, displays the water level in the holdup tank.

Pressure indicator PI-4 measures the pressure of the recirculation line. Flow indicator FI-11 monitors the water flow to the OHCS or to Miscellaneous Haste Holdup Tank and water flow during the recirculation mode.

Pressure indicator PI-13 measures the pressure in the sample line at the sample box, while flow indicator FI-16 monitors the flow of water in the sample line return.

l The sight glasses (FG-5A and FG-58) with the use of remote cameras provide indication of gas flow or no flow conditions l in the effluent line.

All instruments are located above the water level.

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3525-014 1.6.5 Lights Lights are mounted below the DS platform structure to improve visibility of the sight glasses.

1.6.6 Trips'and Interlocks The DS transfer pumps, P-1A and P-T8, &re provided with low level setpoint trips for the holc'up tank, T-1, to ensure that the pumps do not run dry.

The transfer pumps are also equipped with temperature switches that trip the pumps on high temperature.

1.7 System Interfaces The DS interfaces with five (5) systems:

1. Submerged Demineralizer System (SDS) - The DS vents excess argon. gas through automatic vent valves to the holdup tank (T-1). The tank is then vented to the SDS off-gas filter via a tie-in to the 6" off-gas line. In addition, the contents of DS-T-1 may be transferred via V-034 to the Miscellaneous Waste Holdup Tank (HDL-T-2). The SDS Vacuum Outgassing and Drying System may also be used to obtain a gas sample of a dewatered canisterior provide a final dewatering prior to canister shipment.

2. Defueling Water Cleanup System (DHCS) - The DS transfers water from the holdup tank, T-1, to the DHCS for processing. The tie-in is made upstream of the 1HCS lon exchanger K-2. The DHCS motor control center, DHCS MCC 2-32C, supplies 480V, three (3) phase power for the DS transfer pumps. Instrument air is supplied from a DHCS Instrument Air Manifold No. 3 outlet for tank water level indication. DHCS Sample Box No. 1 is used for the DS samole connection location.

3. Fuel Handling Building Canister Handling Bridge and Trolley -

The bridge and trolley locate the defueling canisters which are to be dewatered and covered. The DS platform is designed to provide the necessary clearances to accommodate the canister transfer shield and shield collar.

4. Defueling .inisters - The DS and associated platform are l designed to accommodate the defueling canisters which ar designed by B&W, The DS connections will be operated by long handled tools also designed by B&W. The defueling canisters have a 14 inch nominal 0.D. and 150 inch maximum length. The l- maximum design wet weight of the canisters is 3355 lbs. The canister shell will be straight to within 0.125 inches per 12 l

feet.

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3525-014 5 .' Fuel Handling Building Heating and Ventilation System - The relief valves (R-1A, R-18, R-2, and R-3) on the argon supply lines discharge into a Fuel Handling Building ventilation duct.

2.0 SYSTEM. LIMITATIONS. SETPOINTS, AND PRECAUTIONS 2.1 Limitations The argon cover gas pressure shall be limited by the operators to a maximum 40 psig for all defueling canisters. The argon pressure for backflushing shall be limited by the operator to less than 10 psig for filter canisters and to less than 40 psig for fuel and l knockout canisters..

The transfer pump flow rate is limited to a maximum 30 gpm by DHCS flow control valve DHC-V085 (FV-15) when the water is pumped to the OHCS lon exchanger K-2.

The DS filter canister, F-1, shall not exceed 55 psid pressure differential. When the pressure drop across F-1 approaches this differential, the filter canister is replaced.

The weight of a filter canister af ter dewatering must be at least 199 lbs. less than before dewatering. A value less than this is an Indication that a filter media bubble point may have occurred. The l filter media must be rewetted (Section 3.7.3) and the canister dewatered again.

2.2 Setpoints The pressure safety valve R-3, which is between the argon bottles and the pressure regulators, is set to relieve at 110 psig. The pressure safety valves, R-1A and R-18, on the argon supply lines to the dewatering canisters are set to relieve at 55 psig. The pressure safety valve, R-2, on the argon line for backflushing is set to relieve at 10 psig. However, relief valve, R-2, may be defeated when backflushing a fuel or a knockout canister.

The level indicating switch, LIS-8, trips the pumps when the holdup tank water level drops to 24 inches above the bottom of the tank.

The temperature switches, TS-15A and TS-ISB, trip the pumps when the pumps reach 212*F.

2.3 Precautions The DS operators should visually inspect the hose and fittings which are connected to the defueling canisters prior to dewatering.

Because argon is an asphyxiant, the relief valves on the supply lines discharge to the Fuel Handling Building ventilation exhaust; argon used to dewater is vented to the holdup tank (T-1), which in Rev. 6/0045P

3525-014 turn is vented to the SDS off-gas system. Local sample connections allow small quantitles of argon to be vented directly to the Fuel Handling Building through particulate filter vents.

3.0 OPERATIONS 3.1 Initial Fill Borated water from Spent Fuel Pool "A" is introduced into the holdup tank through valves V018 and V059. A transfer pump, P-1A or P-18, circulates the water through all the system piping, except for the argan supply lines, and the piping is vented.

3.2 Startup The DS has no unique startup procedures.

3.3 Normal Operations

3. 3.1' Pre-Dewatering Checkout Requirements Prior to the start of dewatering, the following requirements must be completed:

1. Recording the weight of the canister,

2. Placing the canister in the support racks, using the canister handling trolley,

3. Connecting the argon supply line and effluent line to the canister, using the dewatering connection tools and DS jlb crane,

4. Isolating the recirculation line and the backflush vent / drains line from the supply and effluent lines, and

5. Isolating the canister train which is not being dewatered from the train which is being dewatered.

3.3.2 Canister Dewatering 3.3.2.1 Filter Canister Dewatering Due to a commitment to disinfect filter canisters, it is necessary to forward flush the filter with a hydrogen peroxide solution. This is only possible if the filter is configured as a normal DS-F-1. After the flush, the DS-F-1 inlet and l

outlet hoses are removed from the filter canister and are connected to the bypass spool piece (U-38). The argon inlet and outlet hoses are then connected to the filter canister so that the canister may be dewatered.

Re/. 6/0045P L

3525-014 Argon is introduced into the filter canister at an initial pressure of approximately 3 psig. The argon pressure is then increased by approximately 1 psi increments, using V002A/B (PCV-1A/B) and indicator PI-2A/B, whenever gas flow, indicated by FI-3A/B, reaches one-half of its previous maximum value.

This pressurization sequence continues until gas bubbles are visible in the sight glass FG-5A/B, at approximately 20 to 40

~

psig. These bubbles, along with a steady flow of argon through FI-3A/B, indicate the canister is dewatered te the extent possible.

The last defueling canister to be dewatered will be the normal DS filter canister, DS-F-1. This canister will be dewatered using the same procedure as described above.

3.3.2.2 Knockout and fuel Canister Dewatering Argon is introduced into the knockout and fuel canisters at an initial pressure cf approximately 3 psig. The argon pressure is then t.iised, using V002A or V0028 (PCV-1A or PCV-18), until gss bubbles are visible in the sight glass FG-5A or FG-58, at asproximately 20 to 40 psig. These bubbles, along with a steady fic'. of argon through FI-3A/B, Indicate the canister is dewatered to the extent possible. The knockout and fuel canisters do not have restrictioiis on the rate the pressure is increased during dewatering.

3.3.3 Canister Gas Covering When the gas bubbles appear in the sight glass, FG-5A or FG-53, valve V004A or V004B is closed and the drain port (effluent line) is disconnected. The canister is filled with arg.n. the cover gas, at 13 to 15 psig. Covering the canister with argon is complete when the flow indicator FI-3A or FI-38 reads ze o. Valve V004A or V0045 is then closed. The canister pressure can be recorded from pressure indicator PI-12A or PI-128 by opening valve V014A or V014B. The argon supply line is then disconnected.

3.3.4 Post-Covering Cr out Requirements The saquence for removing canisters after completing covering operations is as follows:

1. Ensure supply and effluent lines are ciisconnected.

2. Measare the radiation field values of the canister os the canister is removed, if desired,

3. Rcord the canister weight,

4. Reduce pressure in argon supply lire to 1 psig by tileeding argon through valve V006A or V006B, and Rev. 6/0045P

3525-014

5. Close valve V014A or V014B to isolate pressure indicator PI-12A or PI-128.

3.3.5 Transfer DHCS

'Th'e water from the defueling canisters is stored temporarily in the DS holdup tar.k. When the tank becomes full, a transfer pump, P-1A or P-18, is started with HIS-9A or HIS-98 and the l water'Is recirculated throuah filter F-1 by opening valve V025 and closing valves V013A and V0138. .This operation filters the water in a more efficient manner than occurs auring the effluent's first pass. The water is sampled through the sample line by opening valves V028, V029, and the appropriate valves in the sample box. The concentration of the water from the tank should be below 0.S4 uC1/cm3 Cs-137 prior to transferring the water to DHCS. The water is transferred to the CHCS ion exchanger, K-2, by opening valve V030,.or to the Miscellaneous Haste Holdup Tank (HDL-T-2), by opening valves V030 and V034, and closing the recirculation line by closing valve V025. The sample line is closed by closing valves V028 and V029. Hhen the tank level drops between 24 and 36 inches, the pump is stopped with the appropriate switch, HIS-9A or H15-98, and valves V013A and V0138 are opened.

Canisters cannot be dewatered during pump operations because the effluent lines are isolated from the filter, F-1. The canisters can be covered with argon gas during pump operation.

3.3.6 Canister Pressure Check The DS will be used to check the pressure of a defueling canister previously dewatered and covered. The defdeling canister is placed in either of the two (2) canister locations used for dewatering. Valve V016A or V0168 is closed, and the appropriate argon supply line is connected. The canister pressure is read from pressure indicator PI-12A or PI-128 by opening valve V014A or V0148. The cover gas reading may vary from the value recorded when the canister was initially covered because of vaporizattor of water, heating of the cover gas or cooling of the cover gas. The cover gas pressure is adjusted to the original value by adjusting the pressure regulatory, V002A or V0028 (PCV-1A or PCV-18), and opening valve V016A or V016B. The argon isolation valve, V016A or V0168, is then closed. The cover gas pressure is monitored by pressure indicator PI-12A or PI-128. Once the cover gas har been applied, the relief valves are removed and the purge and drain connections are capped. The canister is then monitored for ,ainimum of ten (10) minutes. In this time period, if bubbles from the canister are visible from the DS platform, the canister wiil not be shipped. The leak will be located and repaired, and the canister will be repressurized and pressure checked again bef're shipi ing. Repair procedures for a leaking canister are not within the scope of this document.

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-3525-014 3.4 Shutdown The DS is shutdown by:

1. Isolating the argon gas from the supply line, and

2. Stopping the transfer pump (if operating) and' closing the DHCS and SDS tie-in valves, V030 and V027.

3.5 Draining Draining of the DS is not expected during the life of' the system.

However, the majority of the piping between the dewatering canisters and the holdup tank can be drained to the holdup tank.

Then the tank can be pumped down. The transfer lines and sample lines are provided with low point drains.

3.6 Refilling See Section 3.1, Initial Fill 3.7 Infrequent Operations 3.7.1 Backflushing During. dewatering, it may become necessary to unclog a drain screen in either a fuel or knockout canister. The following conditions would indicate the existence of this situation:

1. A sufficiently high dewatering supply pressure (e.g., 20 to 40 psig), l

2. A stationary sight glass paddle,

3. No gas bubbles visible in the sight glass, and

4. No argon flow through FI-3A/B.

Mckflushing is required to clear a b'ocked canister drain.

For we.ter, the backflush vent / drain line is opened for the appropriate train, while the argon supply line for that train is isolated with the three-way plug valve V006A or V006B. The backflush argon supply line is isolated, while the line to vent valve V044 is opened with the three-way plug valve V043.

The transfer line and the effluent line must be isolated by closing valves V030, V013A, and V0138, respectively. The backflush line is filled by one of two ways: 1) A transfer pump, P-1A or P-18, is dead headed against V030 and V025 with V022 open to fill the line back to V044; or 2) A transfer pump, P-1A or P-1B, is started with V025 open so that the system is in the recirculation mode; then V022 is opened to fill the line back to V044. Valve V022 is then closed and the Rev. 6/0045P

n of 3525-014 argon; supply pressure is adjusted. The three-way plug valve, V043,'is positioned to open the argon line and close the vent line. Transfer pump, P-1A or P-1B, is stopped und valve V015 is closed. The three-way plug valve, V005A or V005B, is positioned to allow the backflush water into the appropriate canister. When backflushing is completed,' valve V025 is closed, valves VOIS, V013A, and V013B are opened, and the three-way plug valves V043, V005A, V0058, V006A, and V0068 are adjusted to their normal positions as shown on Reference 1.

For a backflush using_ argon, three-way_olug valve V006A or V006B is lined up to DS-F-1. The argon supply pressure is adjusted-using V041. Valve V043 is positioned to open tne argon line and_close the vent line. The three-way plug valve, V005A or V005B, is positioned to allow backflush through the appropriate canister. When backflushlag is complete. V041 is closed and the three-way plug valves V043, V005A, V0058, V006A, and V0068 are returned to their normal positions as shown on Reference 1.

3.7.2 Canister Pressure Reduction If a defueling canister is inadvertentiy overpressurized (i.e., P > 15 psig), the pressure may be reduced by bleeding off argon from the canister, through valve V006A or V0068, and the automatic vent valve, V008, to the holdup tank.

3.7.3 Rewetting Filter Media If the filter media buoble point is broken, then the filter canister cannot be effectively dewatered and the media must be rewetted. This situation will be detected by weight measurement after the dewatering canister is disconnected from the DS and is being raised by the CHB (see Section 2.1). The canister is relecated in a 05 rack and a Hansen 1/4 inch tool with a socket is used tc flood the canister or the canister is back filled from DS-T-1 using either DS-P-1A or DS-P-18. A one hour period is allowed to let the water adhere to the filter media before attempting dewatering again.

4.0 CASUALTY EVENTS AND RECOVERY PROCEDURES 4.1 Casualty Events The following five (5) events will shutdown the OS:

1. A lor.s of power will render the transfer pumps, lights, and cameras inoperable,

2. A line break disrupts the dewatering flow naths,

3. A loss of instrument air prevents the tank level indicator from working, Rev. 6/0045P

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, 3525-014 C

4. Canister handling accidents can damage the canister, tools, or portions of the DS, and

5. Filter canister filter media rupture will spread fuel fines throughout the system piping.

4.2 Design Features to Mitigate Effects of Casualty Events The CS mitigates the effects of the events listed in Section 4.1 as follows:

1. Loss of Power - Adverse conditions would not result, but the system should be shutcown (see Section 3.4).

2. Hose or Line Break - Armored hose is being used where possible to reduce the possibility of a hose rupture. This is not a radiological or safety concern because any loss of contaminated water from the DS is insignificant compared with the large volume of borated pool water.

3. Loss of Instrument Air - Adverse conditions would not result, but the system should be shutdown (see Section 3.4).

4. Canister Handling Accident - Canister handling accidents, including drops, are addressed in a separate analysis (see Reference 4).

5. Filter Canister Filter Media Rupture - The maximum pressure in the system is 55 psig. This is below the operating differential pressure capability of the filter.

4.3 Recovery Procedures Recovery procedures for the casualty events listed in Section 4.1 are as follows:

1. Loss of Power - The system is shutdown (see Section 3.4),

power is restored, and normal operations resume (see Section l 3.3).

2. Line or Hose Break - The system is shutdown, the pipe or hose I is replaced, and normal operations resume.

I l 3. Loss of Instrument Air - The system is shutdown, the air i supply is restored, and normal operations resume.

l 4. Canister Handling Accident - The system is shutdoun, if

necessary, the damage is repaired, and normal operations l resume.

i i S. Filter Media Rupture - The filter, F-1, is replaced and the system is run in the recirculation mode (see Section 3.3.5) before normal operations resume.

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3525 014

. m 5.0 MAINTEN NCE-  ;

The maintenance procedures are the recommended practices and intervals as 1 prescribed by instrument ar.d equipment vendors. '

6.0 TESTING 6.1 Hydrostatic Testing All piping and hose will be hydrostatically or pneumatically pressure tested to moet the requirements of ANSI B31.1-1983 Power Piping. '

6.2 Instrument Testing All instruments will be calibrated by the field and verified operational after installation.

, 6.3 Periodic Testing

,- No periodic tests are required.

7.0 HUMAN FACTORS The argon supply hose and effluent hose are different sizes for identification of inlet and outlet canister connections.

Quick disconnects are used for canister connections to facilitate hook-up operations.

i All instruments, valves, and equipment have name plates for I

identification. Controls and instruments are mounted several feed above tne floor or the platform.

i 1  ?

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Rev. 6/0045P 1

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