Published in The Coast Star on April 23, 1998
In addition to preparing to remove the cobalt safely stored in the pool, the remediation team has d one a survey of the area outside checking for cobalt 60 in the soil. There was a cobalt spill in the 1950s which was cleaned up then and again in 1980, according to increasingly strict contemporary standards.
According to Dave Craig, program manager for IceSolv Inc., from Hershey, Pa., the contractor hired by the government to perform the remediation process, the current survey concludes that there are levels of cobalt at the site; however, the levels are so low, they do not pose a public health and safety threat. Surveys of the entire area have gone to the U.S. Nuclear Regulatory Commission (NRC) for approval.
The Evans Area of Fort Monmouth has been used by the Army to support the research and development of communications and electronic equipment, since the beginning of World War II. Use of the radioactive materials supporting the mission began in 1950 and continues today. The NRC regulates the use of radioactive materials through licenses issued to users.
Scientists working at the site in the late 1950s and early 1960s needed a radioactive source for testing and research, so they created cobalt 60.
To make cobalt 60, the scientists bombarded rods of cobalt 59, a naturally occurring isotope which is non-radioactive, with neutrons which attach to the cobalt 59. The neutrons then transform to cobalt 60, a hazardous, radioactive material.
The cobalt 60 was housed in an aluminum-sided pool to shield the researchers from its radiation. According to Mr. Craig, the source, cobalt 60, has been in the area for 20 years.
Cobalt 60 has a 5.27 year half life, meaning that its radioactivity loses energy every 5.27 years, Mr. Craig said.
When the facility was new, the light given off by the rods was strong enough to read a newspaper by. The cobalt stored in the pool has “now gotten to the level that it’s not of adequate strength for a research tool, but still would present a hazard to individuals,” Mr. Craig said.
Because the level of cobalt found via the survey are in such low concentrations, it would not be economically feasible to take remediation action, he said.
“The NRC recognizes that once you get certain isotopes into the soil, there is a level below which they genuinely don’t pose a hazard to public safety. The traces they found the cobalt 60 in are 10 times lower than the NRC’s release limit,” Mr. Craig said.
The NRC, which has been following and checking the remediation process all along, requires a specific license for cobalt 60, which stipulates that it must be stored under 20 feet of water in order to shield people working with it.
To that end, the cobalt has been placed in aluminum rods and stored in an aluminum-sided pool filled with 20 feet of water.
The rods had been in an aluminum matrix. Now hat the rods are old, the aluminum had to be broken free of the cobalt. The team accomplished that, then cleaned the pool, placed the cobalt in containers and out them in the bottom of the pool.
The next step is to place the containers of the rods in shields which are 12 inches thick with lead and steal siding. This shield will bring the rods out and protect everyone in close proximity from the radiation instead of the water.
The cobalt will then be transported by truck, in accordance with all applicable Department of Transportation guidelines, to be buried at a site that has been in operation for 40 years in Barnwell, S.C.
The sources in the pool will be removed next week. Once the sources ate gone, the team will check for residual contamination; the water will go through a filter basin, then mixed resin beds. When it is found safe, it will be released into the sewerage system, Mr. Craig said.
The results of the remediation team’s cobalt testing of the site is currently being reviewed for approval by the NRC.
According to Base Transistion Coordinator Mike Ruane, the entire Evzns area has been surveyed by the remediation team. The surveys have all been sent to the NRC for analysis and release. The surveys of about 100 or 100 acres of the site have already been approved by the NRC; the remediation team is awaiting approval of the surveys of the remaining 90 acreas.
“We anticipate approval from the NRC on the 90 acres in May of June,” Mr. Ruane said.