February 18. 2016 8:45PM

Radioactive material to stay put as factory becomes retail center

New Hampshire Union Leader

The old Sylvania/Osram building on South Willow Street in Manchester on Thursday. (Thomas Roy/Union Leader)

MANCHESTER — Before developers go ahead with the conversion of the former Osram Sylvania light-bulb factory into a $60 million shopping center, they have to address one little problem — a buried vault of radioactive material on the property.

Earlier this month, developer Dick Anagnost disclosed the only containment of its kind in New Hampshire of radioactive contaminated soil.

Reportedly safe, it will be located beneath a portion of the parking lot of the would-be shopping center. But for financing purposes, Anagnost and his partner, Brady-Sullivan Properties, need to carve off a half-acre lot that contains the vault. He has asked the Manchester Planning Board to approve the subdivision.

The concrete vault contains thorium, a radioactive element used at the plant from the mid-1960s to mid-1980s, according to state health officials.

When decommissioning the plant, Sylvania discovered that thorium had contaminated some soil. The contaminated material was encapsulated following guidelines set by the U.S. Nuclear Regulatory Commission, Anagnost told the New Hampshire Union Leader.

“It’s tiny, it’s encapsulated and not dangerous,” Anagnost said. He said radiation-detection equipment was brought on the property and no readings were found. He said further testing is not required; the material is encapsulated for perpetuity.

Anagnost said the vault is about 1,300 square feet and reaches down 10 feet. It is demarcated by brass plates. The vault and plates are currently within a plant building that will be demolished for the shopping center, he said.

Anagnost brought the matter up before the Planning Board two weeks ago. It was apparently the first public disclosure of the spill and containment effort. The state Department of Environmental Services had no records when contacted by a Union Leader reporter.

But the containment vessel is disclosed in the property deed, Anagnost said. And the Radiological Health Section of the state Department of Health and Human Services has a file on the property. The soil contamination was discovered in 1986 when GTE Sylvania hired General Dynamics to decommission the site, said Michael Dumond, chief of Public Health Protection for the state, in an email.

“During this task, it was determined that encapsulation would be a necessary option due to discovery of soil contamination,” Dumond wrote. The deed prohibits any excavation beyond a foot without prior approval of Radiological Health Services, he said.

Named after Thor

Named after the Norse god Thor, thorium is a naturally occurring element. It is prevalent in granite, and the thorium-232 isotope is relatively harmless, with a half-life of more than 14 billion years, said Dr. Samuel Mukasa, dean of the college of engineering and physical sciences at the University of New Hampshire.

But other isotopes have shorter half-lives, which mean they emit more subatomic particles and are more dangerous.

“The most important question to ask is what isotope is it?” Mukasa said.

Anagnost said he’s not aware of the isotope, but a plant manager told him it was a small amount of low-grade thorium.

He said the element was used to improve the illumination of street lights.

Mukasa also said a concrete vault can pose problems. When exposed to groundwater or mud, concrete will deteriorate. And if the radioactive material were liquid, it could cause deterioration.

“When a vault is involved, more questions need to be asked before you understand what’s there,” Mukasa said.

Too costly to remove

In an interview, Anagnost said he hired an environmental engineering firm to research the property. The firm reported that the containment vessel was filled with sand. He said the plant manager told him the thorium had a “life” of 100 years, but he’s not sure what that meant.

Anagnost needs the subdivision because banks will not finance the project if the containment vessel is in the chain of title, he said.

He said the company developing the property, 655 S. Willow St. LLC, will retain ownership of the half-acre once it is subdivided. It would have been too costly to remove the material, he said.

“If it was feasible to have been removed, Sylvania — which is a much bigger company than Brady-Sullivan or Anagnost — would have done that,” he said.

Anagnost and Brady-Sullivan have already purchased the property, and the city has rezoned it. He has yet to bring a site plan forward, but Anagnost said the vault will be below a parking lot near the main entrance to the property, which will be off Driving Park Road. The deed requires that the brass plates remain intact.

When the development was announced, expectations were for 10 to 12 retailers by the end of 2017. The shopping center is expected to generate $1.2 million in tax revenues for the city.

According to Dumond, the Sylvania factory was licensed by the then-Atomic Energy Commission in 1965 to use thorium-dioxide to coat electrodes in high-intensity light bulbs. The process was discontinued in February 1986. Anagnost said the containment was completed in October of that year.