(Bloomberg) — The Nuclear Regulatory Commission thinks the reactor in unit 2 of Japan’s disabled power plant got so hot it “probably melted through the reactor pressure vessel,” U.S. Representative Edward Markey said.
Martin Virgilio, the agency’s deputy director for reactor and preparedness programs, told reporters after a House hearing today that the commission doesn’t think the “core has breached,” which would let radiation escape. The commission gets reports several times a day from agency staff in Japan and none mentioned a breach, he said.
The pressure vessel is one line of defense preventing a larger radiation leak from Fukushima Dai-Ichi’s crippled reactors, where workers have sought to reconnect power to provide a steady supply of water.
“After you lose the vessel, then you are down to one final barrier, that’s the containment,” Virgilio told reporters.
Markey, a Massachusetts Democrat, has pressed for new safety regulations in response to the crisis in Japan, triggered by the 9-magnitude earthquake and resulting tsunami on March 11. Virgilio said workers have yet to stabilize the damaged facility.
Giselle Barry, a spokeswoman for Markey, said information on the status of the unit 2 reactor came from correspondence between his staff and the Nuclear Regulatory Commission.
Markey and Virgilio spoke at a House Energy oversight and investigations subcommittee hearing today on the Japan crisis.
Virgilio said he wasn’t aware of an agency report, cited by the New York Times, that said water used to keep fuel from overheating at the Japanese plant makes containment vessels more vulnerable to rupture amid aftershocks that have rattled the region since March 11.
The report raises the possibility of explosions inside containment structures from the release of hydrogen and oxygen in the seawater pumped into the reactors, according to the Times. The assessment doesn’t speculate on the risk of new explosions or damage from an aftershock, events that may lead to a more serious release of radiation from the nuclear core, the newspaper reported.
The NRC report, dated March 26, offers a “snapshot” of what U.S. experts considered possible conditions inside the station, the agency said today in a statement. It isn’t a reflection of the agency’s “understanding of the current situation,” according to the statement.
The agency offered recommendations to Tokyo Electric Power Co., owner of the crippled plant, which pursued “an alternative set of strategies to control the plants,” according to the statement.
Peach Bottom Risks
Republicans on the committee today said nuclear power plants are safe, as Democrats said accident models developed by the commission raised questions about the Peach Bottom power plant west of Philadelphia.
The analysis showed a two-day loss of power at Peach Bottom would put the plant within an hour of a meltdown, said Representative Diana DeGette, a Colorado Democrat. The model raises “grave questions about our nation’s preparedness to address reactor accidents,” she said.
Representative Brian Bilbray, a California Republican, said living along a coast was more dangerous than being near a nuclear power plant, given the deaths caused by the tsunami after the 9-magnitude earthquake.
Deaths in Japan exceeded 12,500 as of today with more than 15,000 people missing, according to website of the National Police Agency in Tokyo. None of those deaths have been linked to radiation releases, Bilbray said.
Representative Tim Murphy, a Pennsylvania Republican, said Peach Bottom is few hundred feet above sea level and wouldn’t suffer water damage from a tsunami, which wiped out power systems at Fukushima, triggering the crisis.
By Jim Snyder and Jim Efstathiou Jr. – Apr 6, 2011 9:01 PM GMT+0200