Leaks at Minnesota Reactor

By North American Water Office

Events having the potential to affect public health and safety are occurring at Xcel Energy’s Monticello single nuclear power reactor, about 35 miles up the Mississippi River from Minneapolis. Primary cooling water containing tritium (radioactive hydrogen) has been leaking into the ground at least since last November.

Xcel Energy and the Minnesota Department of Health didn’t bother to report the Monticello leak of about 400,000 gallons until mid-March, and then announced, with much fanfare, that there is no risk to public health and safety and that the leak had not reached the Mississippi River. Then, a few days later Xcel Energy announced a second leak of several hundred gallons because the tank into which contaminated water had been collected overflowed. Not bad, for a clown show.

While state and corporate officials say not to worry, the problem is that these same people fail to consider the authority of the National Academy of Sciences in its 2006 report BEIR VII — the Biological Effects of Ionizing Radiation. The book-length BEIR VII conclusively reported that there is no safe dose of ionizing radiation, no level of exposure that can be declared harmless. Every exposure, no matter how small, carries a potential for causing cancers and other mutations.

Considering that the radioactive half-life of tritium is just over 12 years, and that it takes about 10 half-lives before a radioactive substance becomes relatively benign biologically, it is probably premature to speculate about public health and safety impacts. In fact, there are three pathways for leaked radiation to affect the public: it can migrate to the river, which supplies most of the drinking water for Minneapolis; it can migrate into groundwater off-site, where it becomes available for private and municipal water pumps; and it can evaporate. There is no doubt that during the next 120 years, some fraction of the leakage will follow each of these pathways and then affect biological activity. Of course, nobody will ever know how much contamination went where, or know what it did when it got there, because radiation monitoring at Monticello, as well as at the rest of the global commercial nuclear fleet, is mostly incapable of detecting radiation in any of these pathways. It makes better PR to just say there is no threat to public health and safety.

This Monticello pipe leak could be an omen of things to come. The leak occurred because a pipe carrying primary cooling water broke. Primary cooling water circulates through the reactor and thereby becomes radioactive. This radioactivity bombards the pipe through which it flowed with neutrons, and over time, this neutron bombardment causes metals to get brittle. Arguably, the pipe broke because it had become embrittled and something jarred it. The problem here – as with all nuclear reactors — is that every bit of metal at Monticello that is part of the primary system, which contains and controls the nuclear reaction, has also been subjected to this same neutron bombardment. All these metals are at some elevated state of embrittlement, now that the reactor is over 50 years old. As a result, we all now get to sit around and wait to see which components will be next in line to brake, and what the consequences of that breakage will be. That could get real exciting very quickly.

— Additional news on Minnesota reactor troubles can be found at Water for Life, the newsletter of the North American Water Office (nawo.org)