Hanford contractor CH2M Hill Plateau Remediation Co. has received an enforcement letter after a worker picked up a capsule of radioactive material off the floor and others handled it before realizing what it was.
The Department of Energy's Office of Enforcement and Oversight sent the letter just released publicly this week, but did not issue a fine or other penalty for the October incident.
Four Plutonium Finishing Plant workers were exposed to radiation when they handled the material, according to the letter signed by John Boulden III, director of the enforcement office. Their exposure did not exceed occupational limits, but CH2M Hill "narrowly avoided exceeding the dose limits," the letter said.
The capsule was a "radioactive source" used to calibrate radiation detection equipment to make sure it takes accurate readings. It contained strontium 90.
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On Sept. 18, a Plutonium Finishing Plant worker tagged a piece of equipment as out of service because of a mechanical problem with the part that kept the capsule in place and locked the equipment in a cabinet, according to the report.
On Oct. 16, a radiation control technician found what appeared to be a watch or hearing aid battery on the floor and placed it on a desk to decide what to do with it. Before a decision was made, two other workers handled it, but could not identify what it was, according to a report by the Defense Nuclear Facilities Safety Board staff.
The next day, a fourth worker initially thought it was a magnet and handled it. But then the worker noticed the radioactive trefoil symbol on the capsule and identified it as a sealed radioactive source that had fallen from its holder, according to the defense board staff report.
A survey was done then to determine its radioactivity. But a small error in measuring radiation a half-inch from the capsule caused the radioactivity to be under-reported and delayed understanding the potential consequences to workers, the enforcement letter said.
Multiple problems in CH2M Hill's nuclear safety management and occupational radiation programs were identified by DOE and CH2M Hill.
They included weaknesses in documents and records, quality improvement, training and qualification, workplace controls, radiation safety training and written procedures, according to the letter.
CH2M Hill earlier received information shared by another DOE contractor warning that the mechanism that held the capsule in place could degrade over time, the letter said. CH2M Hill had workers perform inspections, but did not train them on how to verify there was not a problem.
The technical document on control of sealed radioactive sources should have provided directions on how to remove defective equipment or repair it, the letter said.
But lacking detailed guidance, a worker used masking tape to label the equipment "do not use" and locked it up. That was a reasonable attempt by the worker to temporarily prevent its use until more action was taken, but it contributed to worker exposure, the letter said.
Workers should have been trained to recognize the radioactive capsules, the letter said.
Once they found an unknown item, which was in an area posted as potentially containing radioactive materials, they should have treated it as possibly being radioactive, the letter said.
The Office of Enforcement chose not to take action beyond sending the letter because CH2M Hill completed a thorough analysis of the event and developed comprehensive actions to prevent it from happening again, the letter said. The enforcement letter drew on many of the findings from CH2M Hill's investigation.
CH2M Hill has improved training for workers responsible for sealed radioactive sources and revised procedures.
That has included developing a process for isolating faulty equipment by bagging and wrapping it and placing it in an isolated, locked location or container with controlled keys, according to CH2M Hill.
-- Annette Cary: 582-1533; firstname.lastname@example.org; Twitter: @HanfordNews