nuclear-news

The reactor pressure vessel for Unit 1, the first of three reactors on site, will get a permanent home in Utah, By TERI SFORZA | tsforza@scng.com | Orange County Register, May 1, 2020   The original plan, nearly 20 years ago, was to plop the retired nuclear reactor pressure vessel on a barge and ship it off — via the Panama Canal or all the way around the tip of South America — to a final resting place in South Carolina.But there were strong objections to transporting the huge metal shell that way. After all, atoms had actually been split inside it. And so the giant, but empty, heart of San Onofre Nuclear Generating Station’s Unit 1 was packed away in a huge steel cylinder in 2002. The cylinder was filled with grout for shielding against radiation. It was sealed, and has been stored at the plant ever since.

Now — as serious tear-down work gets under way on Units 2 and 3 — the heart of long-ago-dismantled Unit 1 is finally slated to leave San Onofre forever.

Operator Southern California Edison is preparing to ship Unit 1’s reactor pressure vessel to a licensed disposal facility in Clive, Utah, which is owned by Energy Solutions, one of San Onofre’s decommissioning contractors. It will have company: San Onofre’s retired steam generators were shipped to Clive in 2012.

Though officials can’t get too specific on precisely when or how the vessel will go — for safety reasons — they’ve been preparing a rail spur to haul heavy components off site.

The reactor vessel is considered low-level waste, the least hazardous of the Nuclear Regulatory Commission’s radioactive waste classifications. Contaminated cleaning supplies, used disposable protective clothing and reactor parts are other examples of low-level waste.

How can the crucible for nuclear reactions be low-level waste? The most radioactive parts within it were removed, cut up, and stored with higher-level waste on site, said John Dobken, a spokesman for Edison. What’s left is Cobalt-60, which has a half-life of about five years.

Unit 1 was retired in 1992, and the reactor vessel has been packaged for 18 years, so it has gone through about five half-lives, reducing its radioactivity, Dobken said.The contact dose rate for the vessel package is less than 0.1 millirem an hour, which is 500 times below the Department of Transportation limit for these types of shipments, Edison said in a primer on the move. For comparison, a chest X-ray provides a dose of 10 millirem.

Since this is low-level waste, it was never part of Edison’s contract with the federal government requiring the U.S. Department of Energy to haul away high-level waste by 1998 in exchange for payments into the Nuclear Waste Fund.

The federal government’s paralysis on finding a permanent home for the nation’s high-level nuclear waste is why 40 years’ worth of it remains stuck on site, generating sharp controversy.

While critics have called on Edison to cease decommissioning work at San Onofre during the lock-down, it proceeds with “pandemic protocols” in place, Dobken said. Everyone on site must wear a mask and practice social distancing.

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By the numbers: The package weighs 770 tons, or more than 1.5 million pounds. Inside is the Unit 1 reactor pressure vessel, pieces of radioactive metal and grout for radiation shielding. It’s a 2-inch-thick carbon steel cylindrical canister with a 3-inch-thick carbon steel liner; top and bottom plates are 3 inches thick. The canister is 38.5 feet long and 15.5 feet in diameter.