TOPIC 3: Shutter Operations

Let’s explore producers for checking the shutters.

—

There are many different types of shutters.

This one the shutter is a vertical cylinder with a hole in it.  It is rotated 90 degrees to allow the beam to pass through the cylinder hole.

—

This shutter is a simple PUSH – PULL.  To move the source to the hole, the plunger is pushed.  To shutter the beam, the plunger is pulled out.

—

This shutter is on a horizontal lever that rotates the shutter to block or “close” the source.   To “open” the shutter, the handle is rotated which allows the beam to go through.

—

This shutter is tied to the source and the whole shutter rotates with the source to allow it to be exposed.  The shutter locking mechanism is on the back side which allows the user to lock the lever in the “CLOSED” position.

—

How do you do a shutter check?

• Use a calibrated survey meter and measure the radiation levels as close to the shutter as you can.
• Close the shutter and see a drop in radiation.
• Return the shutter to the open position.

Can you do a shutter check without a portable survey meter?

• Yes. Use the mounted detector opposite the source holder.
• Communicate with the Control Room that the shutter is to be closed.  Have the operator tell you when there is a change in the signal in the Control Room.
• Return the shutter to the open position.

Who can do a shutter check?

• An 8-hour Authorized User
• The Advanced Authorized User (40-hour)
• The RSO or the manufacturer of the device.

—

What is the difference between Shutter Check and Lockout/tagout (LOTO)?

Verifying a shutter can be closed does not require a lock

Locking a shutter closed may or may not fall under the facility’s LOTO procedures.

Locking a shutter for operational concerns does not require personal locks on the Source.

Only if the source is locked for safety from someone working in the area.

Operationally, only an 8-hour Authorized User, the Advanced Authorized User (40-hour), the RSO or the manufacturer of the device can lock the source.

But – always, always follow the facility’s LOTO procedures if the lock is required for safety reasons.