Reactor Cavity Decontamination

Quality Nuclear Services, Inc. offers two separate processes for reactor cavity decontamination. Both methods are very effective in reducing contamination to acceptable levels for cavity work. QNS provides experienced personnel, equipment and supervision to perform reactor cavity decon using strippable coating or ALCONOX applications.

Strippable Coating:

Strippable coating is an effective method for controlling the spread of contamination, especially where hot particle control is necessary. The paint is applied to the cavity walls and floor by means of an airless sprayer. QNS uses a Graco sprayer for all strippable coating applications.

Advantages:

  • Good decontamination factor
  • Minimal rad-waste produced
  • Immobilizes hot particles
  • Low risk for airborne radioactivity
  • Produces NO liquid waste

Disadvantages:

  • Overhead crane support required for application and removal
  • Cavity must be dry prior to application
  • Minimum of 4 hours cure time prior to placement of floor mats

ALCONOX:

The ALCONOX method of cavity decon is a basic, labor intensive process. The attractive feature of this process is that no overhead crane support is required and, therefore, does not impact critical path activities.
ALCONOX is a precision cleaning detergent that is injected through a pressure washing system and sprayed on the reactor cavity walls and floor. As the walls are being sprayed technicians scrub the walls with extendible poles and scouring pads. The cavity surface is then pressure washed using demin water to remove the residual soap and to achieve the lowest contamination levels possible.

Advantages:

  • NO overhead crane support required
  • Cavity decon can be completed in 12 hours or less
  • Very good decontamination factor

Disadvantages:

  • Relatively new process
  • Labor intensive
  • Detergent cannot be applied until drain down is complete and proper system alignment is achieved

QNS uses an electric pressure washer for this process. It requires a 480 volt, 3 phase power supply for operation. The washer output pressure is adjustable from 400-3000 psi and dispenses water at a rate of up to 4.8 gallons per minute. A floor cleaning attachment may also be used to clean the cavity floor.