Sodium metasilicate with a hardening agent helped to plug a radioactive water leak at the damaged Japanese nuclear reactor
Over the weekend, workers at the ill-fated Fukushima Daiichi Nuclear Power Station attempted to plug a leak in the reactor with a polymer mix, but initially failed. According to reports in The Wall Street Journal and The New York Times, Japanese officials found that radioactive water was leaking directly from the nuclear plant, ruined by the March 11 earthquake, into the Pacific Ocean from a crack on the reactor’s premises.
The leak was found at a maintenance pit near the plant’s No. 2 reactor. The pit, also called a chamber, connected to a tunnel for cables running to the No. 2 reactor, and is normally used to inspect electrical cables that power the intake of ocean water to cool the nuclear fuel.
The crack in the pit was about eight inches wide. When the leak was discovered, the roughly six-foot-deep pit had between four and eight inches of contaminated water. Officials were unable to assess how much water had escaped and for how long.
Workers had tried to fill the crack with concrete on Saturday, but the concrete didn’t seem to set, according to business reporters Ken Belson and Hiroko Tabuchi in their New York Times article. The next day, Toko Sekiguchi and Takashi Mochizuki reported in The Wall Street Journal that the workers poured “132 pounds of sawdust, 18 pounds of polymer and three bags of shredded newspaper into the pit.”
That Sunday night, regulators said that the materials hadn’t absorbed the radioactive water, which kept flowing into the sea. Officials didn’t understand why the concrete or other attempted fixes at first failed to plug the crack. Their efforts were eventually successful, however.
Science and medical writer Thomas H. Maugh II reported on Wednesday in the Los Angeles Times:
After several failed attempts to halt the leak, engineers finally succeeded Wednesday afternoon by pumping in a silicon-based polymer sometimes referred to as liquid glass. They planned to then pour concrete on top of the polymer to further seal the leak.
Liquid glass, also known as water glass, is sodium metasilicate (Na2SiO3). It’s used in cements, passive fire protection, and automobiles.
Source:Â ”Japan’s Efforts to Plug Leak Fall Short,” The Wall Street Journal, 04/04/11
Source: “Japan Struggles to Plug Leak as Radioactive Water Seeps Into the Sea,” The New York Times, 04/02/11
Source: “Engineers try to lower danger level at crippled Japanese nuclear plant,” Los Angeles Times, 04/06/11
Copyright-free image by Chemicalinterest via Wikimedia Commons.
Rajendrani "Raj" Mukhopadhyay is a science writer and editor who contributes news stories and feature articles on scientific advances to a variety of magazines. Raj holds Ph.D. in biophysics from Johns Hopkins University.
