ML20212H585

Rev 5 to Process Control Program for Processing of Radioactive Wet Waste

ML20212H585
Person / Time
Site:	Quad Cities
Issue date:	02/11/1987
From:	COMMONWEALTH EDISON CO.
To:
Shared Package
ML20212H508	List: ML20212H503 ML20212H570 ML20212H585
References
PROC-870211, NUDOCS 8703060156
Download: ML20212H585 (9)

Text

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L '0UAD-CITIES STATION 1

PROCESS CONTROL PROGRAM .

t-i FOR ,

f PROCESSING OF RADIOACTIVE WET WASTE

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s I. PURPOSE

-The purpose of this Process Control Program (PCP) is to insure that all low tevel radioactive wet wastes solidified or dewatered at Quad-Cities Nuclear Power Station meet the applicable federal, state, and burial site requirements. This PCP sets forth the steps used to solidify or dewater. radioactive wet wastes and to verify the final product meets the applicable requirements. This program covers the in-plant cement, i- vendor cement and vendor dewatering systems. Wet wastes at Quad-Cities Station consist of filter media (powdered resin and fiber) and bead

. resin. When expended, these wastes are transferred to various storage tanks.

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11. IN-PLANT CEMENT SOLID WASTE SYSTEM DESCRIPTION (Class A unstable waste form only)

The resin slurry is transferred to one of two centrifuges for l

dewatering'. The centrifuges have a capacity of 25 gpm. The solids are

( separated from the water and drop into a hopper associate'd with each centrifuge. The water is routed back to a storage tank.

Each hopper has a 40 cubic foot capacity. At the bottom of the hopper there is a hopper discharge valve. This is a remotely operated, air-operated, fail closed valve. Connected to the hopper discharge valve is the sludge chute and the drum feed valve. The sludge chute is 8 inches l

in diameter and 6 feet 5 inches long, with a capacity of 2.2 cubic feet.

i l The drum feed valve is also remotely operated, air operated, and l

l: fail-closed. The hopper discharge valve and the drum feed valve are l

interlocked to prevent both valves from being open simultaneously.

Coment is added to a drum from the cement silo. The cement silo has a capacity of 620 cubic feet. Cement is fed through a i

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. . . rotcry feed 3r dL:n a transfer tuba through tha mixer herd, into the drum. The mixer goes into the drum and forms a seal to prevent dispersi6n of cement dust or spillage during mixing. The mixer has two speeds, 100 rpm and 200 rpm, that are programmed into the mix cycle.

Drums are capped at the load-out conveyor area before loading into a shipping cask. A cap is set in place and a seal ring is snapped over it. A threaded bolt is used to tighten the seal ring.

Drum storage consists of three conveyor lines, with room for 25 drums on each line. Drums stored on the storage lines are removed and either shipped, stored in storage bins located in the radwaste facility, or stored in the Interim Radwaste Storage facility.

Ill. OPERATION OF THE IN-PLANT CEMENT SOLID WASTE SYSTEM In order to insure solidification of spent resins with no free water, tests were conducted at Quad-Cities Station using unspent resin.

Fresh resins were mixed up in the proportions that would be expected to be normally processed. These resins were then put into a drum and the drum was processed through the cement system. The drum was capped as normal and allowed to set in storage for 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. After 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, the drum was cut open lengthwise and inspected. The results of the inspection resulted in a change of the proportions of water and cement until the final product was solid and free of water. A series of drums were processed using spent resins, and the drums were visually inspected for no free water prior to shipping. No free water was observed.

The general procedure that is followed to process spent resins is

described below. Specific plant operating procedures are followed by the l operator.

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• A. Tha empty drum is c:vered nith a plastic big and taped in pirce to prevent external contamination.

B. A half'of a bag of dry cement is added to the empty drum.

C. .The empty drums are loaded on a conveyor.

D. . One empty drum from the conveyor is loaded on a transfer cart (remote operation).

E. The transfer cart is advanced to the selected hopper station (remote operation).

F. Water is added (remote operation). Normally 12 gallons of water are added to each drum. This amount can be varied if necessary for complete solidification. The amount of water required is selected, and a flow integrator gives the inlet valve a closed signal when that amount is delivered.

G. The drum is filled with resins to a prescribed level (remote operation). The resin is transferred from the hopper to the drum through the sludge chute. The discharge valve on the sludge chute is a manually operated remote valve. The operator views the drum through a mirror and fills the drum to the first roll hoop f rom the top of the drum. Although this method of adding resin to the drum is not precise, it can be controlled to a high degree. If an operator determines that the quantity of resins varies from the prescribed level, he can compensate with water and/or cement.

H. The drum is transferred to the mixing station (remote operation).

1. The cement timer is set.

J. The mixer cycle (remote operation) is started. The mixer lowers into the drum and forms a tight seal. The mixer will begin to 01530

,, ,- rotats at slow sp2ed. Tha air slide bloxsr end dust collector are

< started. The cement feeder end vibrators start and cement is metered to the drum. The mixer increases to fast speed. The cement feeder stops and the air slide blower and dust collector stop. When the mixer completes the cycle, the RPM meter will start to decrease. At this point, the mixer control switch is moved from AUTO to FAST and the mixer is given an additional 5 minutes on fast speed. The switch is then returned to AUTO, and the mixer cycle is complete.

K. The drum is transferred to the inspection station (remote operation).

L. The mixed drum contact radiatior, reading are logged and the contents of the drum are observed. If it is determined that more cement is required, the drum is returned to the mixer and additional cement is added. When the mix is satisfactory, the drum is transferred to the drum storage lines.

IV. VERIFICATION OF IN-PLANT CEMENT SYSTEM SOLIDIFICATION The solidified drum is verified to be void of free water prior to shipping or storage. The drum is transferred from the storage lines to the load-out conveyor. At this point, the drum is visually verified to be void of free water, the protective plastic bag is removed, and the drum is capped. The drum is then surveyed for smearable contamination and dose rate. The drum is then loaded into the shipping vehicle or placed in storage.

If a drum is found to contain free water, it will be noted as such.

Dry cement will be added such that all of the free water is, absorbed or the drum will be recycled through the mixing line as required. The drum will not be shipped until all free water is absorbed.

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.. , V. VENDOR SUPPLIED SOLIDIFICATION SYSTEM (Stablo Waste. Forms)

Contractor solidification services are utilized at the Station for wastes which are required to be classified as stable waste per 10 CFR 61 and/or burial site licenses. The contractor must have a PCP (Process Control Program) to produce a waste form which is stable as defined in 10 CFR 61. Solidification is done in either the cask or a process shield i

and offers the advantage of reduced radiation exposure to personnel involved in performing the necessary package handling operations.

A batching tank is utilized to collect the radwaste to be solidified. The tank can be filled from any of the following:

Condensate Phase Separators.

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B. Cleanup Phase Separators.

C. Spent Resin Tanks.

D. Waste Sludge Tank.

E. Floor Drain Demineralizer.

After the tank is filled with radwaste, a decant pump is used to remove water from the top of the settled sludge. When the decanting operation is completed, the tank contains about 1,900 gallons of sludge.

The mixing tank is operated on recirculation in order to allow a l

tank sample to be taken for analysis and sample solidification tests.

A temperature monitor in the liner is used to note the maximum temperature during the exotherm. After sufficient cooling the liner is prepared for shipment or storage.

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1. , s VI . OPERATION OF THE VENDOR SOLI 0lFICATION SYSTEM A liner. is prepared for use by installing a thermocouple and tubing for level indication. The fill _ head is placed over the. liner and locked in-place.

The radwaste is added to the liner. The mixing tank is first mixed for about 10 minutes. The proper amount of radwaste is delivered by the radwaste pu.np. Waste flow to the liner is monitored by a TV camera. The radwaste pipe lines and waste transfer hose to the fill head are then flushed.

After the radwaste has been put into the liner the process is L

completed by the contractor. The contractor adds cement and additives in accordance with their approved PCP. After final mixing the temperature is monitored and the maximum temperature is noted. When the solidified liner has suf ficiently cooled the contractor visually inspects the product and verifies that it is an acceptable product. The liner is then-covered with a lid, secured, surveyed and shipped or stored in the j interim Radwaste Storage Facility.

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l l' Vll. VERIFICATION OF VENDOR SUPPLIED SOLIDIFICATION SYSTEM Verification of solidification first involves sampling the radwaste prior to solidification in order to determine the proper proportions of the ingredients that will produce an acceptable product. A l

representative laboratory sample of waste is taken from the sampling 1

line. Small, scaled-down amounts of cement and additives are added in the proper quantities. Based on an acceptable product, scale-up factors are developed for the full scale solidification.

To further verify solidification, a visual inspection of the liner is performed prior to installing the lid. The visual inspection verifies that the product is acceptable per the contractors PCP.

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, , pl I . VENDOR SUPPLIED DEWATERING SYSTEM (STABLE WASTE FORMS)

Contractor dewatering services may be utilized at the Station in lieu of solidification for stable waste forms as directed by station operating personnel. The contractor cust have a Process Control Program (PCP) to produce a waste form which meets all the requirements of 10CFR61 and the applicable burial site criteria. Dewatering may either be done in a cask or a process shield.

A mixing tank is utilized to collect the radwaste to be dewatered.

The tank can be filled from any of the following:

A. Condensate Phase Separators B. Cleanup Phase Separators C. Spent Resin Tanks D. Waste Sludge Tank After the tank is filled with radwaste, a decant pump is used to remove water from the top of the settled sludge. When the decanting operation is completed, the tank contains about 1,900 gallons of sludge.

The mixing tank is operated on recirculation in order to allow a tank sample to be taken for analysis.

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, ,, L X . OPERATION OF THE VENDOR DEWATERING SYSTEM A High: Integrity Container (HIC) is prepared for use by installing a thermocouple, if not already installed, tubing for level indication, and inspecting dewatering elements and thermocouple leads, if installed. The fill head is placed over the liner and locked in-place.

The radwaste is added to the HlC. The mixing tank is first mixed for approximately 10 minutes. The proper amount of radwaste is delivered by the radwaste pump. Waste flow to the HIC is monitored by a TV camera. The radwaste pipe lines and waste transfer hose to the fill head are then flushed.

After the radwaste has been put into the HIC, the process is completed by the contractor. The contractor dewaters in accordance'with their approved PCP until the acceptance criteria is met. When the process is complete, the contractor verifies that it is an acceptable product. The HIC is then covered with a lid, secured, surveyed and shipped or stored in the Interim Radwaste Storage Facility.

X. VERIFICATION OF VENDOR SUPPLIED DEWATERING SYSTEM Verification of an acceptable dewatered product is delineated in the l

contractors Process Control Program and operating procedures. The criteria is dependent upon the type of dewatering system used and the l

material dewatered.

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