A record high level of beta rays released from radioactive strontium-90 has been detected at the crippled Fukushima nuclear power plant beneath the No. 2 reactor’s well facing the ocean, according to the facility’s operator.
Tokyo Electric Power Company (TEPCO) measured the amount of beta ray-emitting radioactivity at more than 2.7 million becquerels per liter, Fukushima’s operator said as reported in Japanese media. The measurements were taken on Thursday.
There has been a spike of radiation in this area since the beginning of the year. The measurements taken on Monday showed 2.4 million Bq/l, while the results taken on January 9 indicated the amount of beta rays at 2.7 million Bq/l, according to TEPCO’s Friday announcement.
Strontium-90 is a “bone seeker” that exhibits biochemical behavior similar to calcium, the next lighter group 2 element. After entering the organism, most often by ingestion with contaminated food or water, about 70–80% of the dose gets excreted. Virtually all remaining strontium-90 is deposited in bones and bone marrow, with the remaining 1% remaining in blood and soft tissues. Its presence in bones can cause bone cancer, cancer of nearby tissues, and leukemia. The overall biological half life is estimated to be about 18 years.
Strontium-90 was among the most important isotopes regarding health impacts after the Chernobyl disaster. As strontium has an affinity to the calcium-sensing receptor of parathyroid cells that is similar to that of calcium, the increased risk of liquidators of the Chernobyl power plant to suffer from primary hyperparathyroidism could be explained by binding of strontium-90.
In March 2011 an earthquake triggered a tsunami that hit Japan’s coast, damaging the Fukushima Daiichi nuclear power plant. The catastrophe caused the meltdown of three nuclear reactors at the facility, leading to the worst nuclear disaster since Chernobyl.
The water used to cool the reactors has been leaking into the soil and contaminating the ground water ever since. Some of the radioactive water has been escaping into the Pacific Ocean.
TEPCO plans solve the problem by setting up special equipment to freeze the ground around the reactors. The works which are to start this month include plunging tubes carrying a coolant liquid deep into the ground. The coolant would freeze the ground solid so that no groundwater could pass through it.