Credited Controls at C-AD Photo of the Week E. Lessard Collider-Accelerator Department Take 5 for Safety

Credited Controls Policy  DOE requires that C-AD management address non-standard industrial hazards in the Accelerator Safety Envelope (ASE) by identifying specific Credited Controls  At C-AD, specific Credited Controls provide protection from the following non-standard industrial hazards  exposure to ionizing radiation from accelerator beams  airborne radioactive material from accelerator targets  oxygen deficiency hazards involving liquid helium or SF 6 releases  For 9 C-AD accelerators and 8 accelerator facilities, there are 144 Credited Controls in 6 ASEs  Non-credited controls (e.g., PPE, training, SBMS requirements, etc.) also protect people and the environs, but are acknowledged as defense in depth for standard industrial hazards and not included in the ASE 2

Determining Credited Controls  Determining Credited Controls is based on risk but it is an art and not a science  For a specific event, C-AD determined the event frequency range and potential consequences range by engineering judgment, actual data and/or engineering analyses  In the Table in the next slide, the green risk levels for non-standard industrial hazards are where C-AD chooses to operate the accelerators  C-AD does not operate in the orange risk levels  No hard divide between unacceptable and acceptable risk  C-AD adds additional Credited Controls to reduce risk to an “acceptable” level  C-AD does not operate in the red risk levels 3

C-AD Consequence, Frequency, Risk and Control Template 4

Criteria for Extremely-Low Consequence Events  Extremely-low consequence events do not result in a significant injury or occupational illness or do not significantly affect the environs  C-AD uses ALARA Controls for these types of events even if they occur frequently  Example events are routine radioactive emissions  On the other hand, C-AD values the trust of the public and the regulators, and identifies Credited Controls for tritium in the ground water, which is an extremely-low consequence event for an accelerator:  Rainwater impermeable caps over activated soils require semi-annual inspection  C-AD has identified cap inspection as a Credited Control in the ASE in order to provide additional quality control, design margin, and operational attention to this control  Selecting Credited Controls is more of an art than a science and selection depends on economic and social factors, not just regulations or risk 5

Orange to Green for Soil Caps Leaks 6

Criteria for High-Consequence Events  High-consequence events cause serious impact onsite or offsite (deaths or loss of facility/operation and a) significant impact on the environment or b) significant concern on the part of the public or the regulators)  C-AD’s Table of Controls indicates ALARA, Regulatory Controls, SBMS Controls and Credited Controls for these events if the frequency of occurrence is greater than once in 10,000 years  C-AD considers risk of immediate radiation injury from beam unacceptable even though the Access Controls System (ACS) for preventing radiation deaths or injuries has an estimated failure rate less than once in 10,000 years  Even if there is no environmental impact, regulators and the public would be extremely concerned about a radiation injury  C-AD has identified the ACS as a Credited Control in order to provide additional quality control, design margin, and operational attention to the radiological hazards from accelerator beams 7

Orange to Green – ACS Credited Control Added to Prevent Exposure to Beams 8

Photo of the Week - Fall Protection Isn’t Actually Fall Protection 9 US Navy workers had to lift an antenna dome, and before they started, fall protection was inspected The stanchions were made of thin aluminum, with bases bolted on the platform with rusted quarter-inch bolts, and the chain was quarter-inch plastic The chain and stanchions had originally been installed to prevent electromagnetic interference; one problem solved, two more created