WOOD RIVER JUNCTION, R.I. — Fifty-two years ago this July an explosion rocked this rural village and devastated a local family.

On July 24, 1964, an accident occurred at the United Nuclear Corp.’s fuels recovery plant, killing a 37-year-old production technician. On the evening of the accident, Robert Peabody was reportedly pouring what he thought was a bottle of trichloroethylene, to remove organics, into a mechanical mixer when he saw a blue flash. He had accidentally poured a concentrated uranium solution into the mixer, which contained sodium carbonate, resulting in a critical nuclear reaction.

With so much uranium in one container, it reached critical mass and reacted, knocking Peabody to the floor, splashing him with radioactive liquid and exposing him to a fatal radiation dose of 10,000 rads (1 rad equals 0.01) — 1,000 times the lethal dose and the equivalent of 700,000 chest X-rays. Peabody, bombarded by neutrons and gamma rays, had been exposed to more radiation than anyone outside of Hiroshima or Nagasaki, Japan, two decades earlier.

Peabody died two days later. His wife and their nine children were left with a small cash settlement. The accident was blamed on a combination of factors, including incorrect procedures approved by supervisors.

The Atomic Energy Commission eventually charged United Nuclear Corp. with 14 violations of nuclear-safety regulations, eight directly involved in Peabody’s accident, but no fines were ever imposed.

When the United Nuclear facility had opened four months earlier, then-Gov. John Chafee called it “a tremendously exciting thing for us here in Rhode Island,” according to a 2000 New York Times story.

However, the now long-closed nuclear facility also left behind another legacy.

Plume of pollution
The facility was designed to recover uranium from scrap material left over from fuel-element production. The plant took uranium scrap, spent fuel rods from reactors or the dross from manufacturing, dissolved the material in acid and passed it through a series of processes to recover enriched uranium, according to a 1994 Yankee magazine story. There was no nuclear reactor.

The facility, in southwestern Rhode Island, closed in 1980, 16 years after Peabody’s death. The company and federal government then began a multimillion-dollar, decades-long decontamination of the 1,114-acre site at the elbow of the Narragansett Trail. The Pawcatuck River flows through the property’s northwest corner.

The Nuclear Regulatory Commission declared the site safe in October 1995. In 2011, state and federal officials determined no further clean-up action was required. Last month, The Nature Conservancy removed 3,000 feet of chain-link fencing that had formerly surrounded the facility.

But for nearly two decades the nuclear plant dealt with some nasty stuff. Acid digestion with hydrofluoric and nitric acids and organic separation with tributyl phosphate and kerosene were used to extract uranium from test-reactor fuel rods, from machinery used in their manufacturing, and from miscellaneous laboratory and hospital equipment. Solid wastes from the process were shipped off-site, and lime-neutralized liquid wastes were initially discharged into the Pawcatuck River through a drainpipe and later to “evaporation” ponds and trenches.

From 1966 to 1980, liquid wastes, containing radionuclides and other chemical solutes, were discharged into the environment through those uncovered ponds and trenches. Overflow problems caused by precipitation and disposal-flow rates, which ranged from 360 to 1,400 gallons a day, according to a mid-1980s report, led to the periodic construction of additional ponds and trenches.

Leakage from all these ponds and trenches, which ultimately encompassed about 25,000 square feet, resulted in a plume of contaminated groundwater that extended northwestward to the Pawcatuck River, through a highly permeable sand and gravel aquifer.

Among the chemicals used at the plant in the recovery and waste-treatment processes were aluminum nitrate, ammonia, boron salts, chlorothene, mercury, oxalic acid, potassium hydroxide, sodium hydroxide, strontium carbonate and tributyl phosphate.

The possibility that future drinking-water supplies might become contaminated, as a result of the migration of contaminated water from the facility, was a concern noted by local water managers and residents.

In April 1981, the U.S. Geological Survey (USGS) began a 3.5-year study of groundwater contamination in and around the Wood River Junction site, as part of its Low-Level Radioactive Waste Program.

The study’s objectives were to identify chemical and radiochemical constituents in the plume; assess the interaction of solutes with the aquifer materials; determine the location, movement and fate of constituents in the plume; and estimate the effects of groundwater contamination on future development near the site.

Water quality data from about 150 observation wells indicated that the plume was about 2,300 feet long and 300 feet wide, according to the USGS report. Chemical and radiochemical constituents in the plume included boron, calcium, nitrate, potassium, strontium-90 and technetium-99.

Of greatest concern, from a public-health standpoint, were nitrate and strontium-90. The maximum nitrate concentration exceeded the maximum contaminant level by 73 times, and the maximum strontium-90 concentration exceeded drinking-water criterion by 36 times, according to the report.

Water-quality data from wells screened at multiple depths on both sides of the Pawcatuck River indicated that contaminants discharged into the river and to a swampy area west of the river.

The 102-page study concluded that groundwater quality in the Wood River Junction area would be affected by the plume but probably not enough to prevent development of water supplies, if pumping rates are limited to about 0.25 million gallons daily.

For the past 36 years, however, the site of a horrible death and a source of environmental contamination has been on the road to recovery.

Wildlife habitat
The 1,112-acre Francis C. Carter Preserve, off Route 112 in Charlestown and Richmond, was once the home of the United Nuclear plant. When United Nuclear owned the property, the company only used about 12 acres for its operations, so most of the property had been undisturbed for decades.

Today, the site is the second-largest Nature Conservancy property in Rhode Island. In 2014, after additional contaminants were removed, The Nature Conservancy took ownership of the remaining 271 acres, which included a mile of riverfront. After the first phase of the cleanup was completed, in 2001, the conservancy obtained the initial 841 acres from General Electric, which had bought out United Nuclear. Grants from The Champlin Foundations made both purchases possible.

“Securing the fields and forest next to the Carter Preserve has been one of the conservancy’s highest land protection priorities for over a decade,” Terry Sullivan, state director of The Nature Conservancy in Rhode Island, said at the time. “It is a special place in terms of its biodiversity and it is one of the largest and most beautiful protected areas in South County.”

The preserve provides habitat for nearly a third of Rhode Island’s bird species of greatest conservation need, according to The Nature Conservancy.

The conservancy is currently expanding grassland by clearing poor-quality pines and removing invasive shrubs, such as autumn olive and multiflora rose. This work will help restore field and shrub habitat, with direct benefits for American kestrels, grasshopper sparrows, prairie warblers and more than a dozen other bird species.

The preserve’s forested wetlands now play an important role in absorbing stormwater and protecting water quality downstream.