nuclear-news

The U.S. Energy Department said workers at Washington state’s Hanford Nuclear Reservation detected higher radioactivity levels under tank AY-102 during a routine inspection Thursday……. AY-102 is one of Hanford’s 28 tanks with two walls, which were installed years ago when single-shell tanks began leaking. Some of the worst liquid in those tanks was pumped into the sturdier double-shell tanks.

The tanks are now beyond their intended life span.

Two radionuclides comprise much of the radioactivity in Hanford’s tanks: cesium-137 and strontium-90. Both take hundreds of years to decay, and exposure to either would increase a person’s risk of developing cancer.

The Energy Department announced last year that AY-102 was leaking between its two walls, but it said then that no waste had escaped.

However, Seattle television station KING5 has reported that the cleanup contractor knew a year earlier that the tank was leaking.

Mike Geffre, an instrument technician who works for contractor Washington River Protection Solutions, said Thursday’s inspection came from a pit under the tank, like a saucer under a teacup. Water samples from the pit had an 800,000-count of radioactivity and a high dose rate, which means that workers must reduce their time in the area.

“Anything above a 500 count is considered contaminated and would have to be disposed of as nuclear waste,” Geffre said. “Plus, the amount of material we’ve seen from the leak is very small, which means it’s a very strong radioactive isotope.”……..

Today, it is the nation’s most contaminated nuclear site, with cleanup expected to last decades. The effort — with a price tag of about $2 billion annually — has cost taxpayers $40 billion to date and is estimated will cost $115 billion more.

The most challenging task so far has been the removal of highly radioactive waste from the 177 aging, underground tanks and construction of a plant to treat that waste.

The one-of-a-kind plant, long considered the cornerstone of Hanford cleanup, will encase the waste in glasslike logs for permanent disposal. But workers designing and building it have encountered numerous technical problems, delays and skyrocketing costs.

The latest concerns center on adequate mixing of the waste, with the potential for explosions if radioactivity is allowed to build up in one area, and erosion and corrosion in vessels and piping. Last priced at $12.3 billion, the cost is expected to rise further….. http://www.wunderground.com/news/nuclear-waste-site-washington-state-leaking-again-20130625