English below
Rekordowe odczyty radiacji w Fukuszimie
Wg TEPCO, po raz pierwszy od początku katastrofy (11.3.2011) zmierzono rekordowe poziomy radiacji w podziemiu reaktora 1, co opóźni oczyszczanie siłowni w Daiiczi. Odczyty uzyskano po wprowadzeniu instrumentów przez otwór w suficie. Ponad lustrem skażonej wody, radiacja wynosi 10,3 tys. milisievert/godz. — tj. podniesiony po katastrofie limit dla ratowników osiąga się po 20 sekundach ekspozycji. Dawka może zabić szybciej niż po 1-godzinnym napromieniowaniu. ratownicy nie mogą więc wejść do podziemii w celach robót. Wg TEPCO, tak wysoki poziom radiacji w reaktorze 1 (ok. 10 razy wyższy niż w uszkodzonych reaktorach 2 i 3) pochodzi z większej liczby stopionych prętów paliwowych niż z początku przypuszczano.
Plan ratunkowy Daiiczi przewiduje demolkę 3 uszkodzonych reaktorów i bloku 4 (opróżniony reaktor w momemencie katastrofy, ale przeładowany basen ze zużytymi prętami paliwowywmi), co potrwa 40 lat i będzie wymagać opracowania nowych technik.
Do zagrożeń dołączył sezon tajfunowy, który może dalej zniszczyć obiekt w Daiiczi i spowodować więcej wycieków promieniotwórczych. Wg Kazuhiko Kudo, profesora inżynieri reaktorów na U. Kjusziu, tornado o szybkości wiatru 100 m/sek mogłoby wyssać ciecz z gołych basenów 3 i 4, obnażając pręty paliwowe [co spowodowałoby reakcje łańcuchowe].
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Record high radiation levels detected at Fukushima reactor
Tuesday, July 03, 2012 by: J. D. Heyes
(NaturalNews) – Measurements taken recently at the tsunami-damaged Fukushima nuclear complex in northern Japan have revealed record levels of radiation contamination, officials with the plant’s operator, Tokyo Electric Power Company, said.
The elevated contamination levels were discovered in the basement of reactor No. 1, officials said – a discovery that will further delay and impede operations aimed at cleaning up the site. It was the first internal measurement carried out since three of the plant’s nuclear reactors were damaged by a tsunami caused by a major earthquake off Japan’s northeastern coast in March 2011.
TEPCO engineers reportedly gathered samples from the basement after inserting a camera and consulting measuring instruments through a drain hole located in the ceiling of the basement.
The company said radiation levels above radiation-contaminated water in the basement measured as high as 10,300 millisievert per hour – a dose plenty high enough to kill human beings in short order after making them sick within minutes.
Radiation levels even higher than anticipated
Put another way, the annual allowable dose for plant workers at the site is reached in just 20 seconds. One report said the dose was enough to kill humans in less than an hour.
“Workers cannot enter the site and we must use robots for the demolition,” said TEPCO, in a statement.
TEPCO official, Junichi Matsumoto said he believed there was a higher radiation level in the No. 1 reactor because more fuel rods than suspected melted down following the incident.
The power company said radiation levels there were 10 times what they have measured at the plant’s other damaged reactors, numbers two and three. In all, the Fukushima plant contained six reactors.
The meltdown of the reactors came after the tsunami managed to cut power to their cooling systems.
The plan now is to demolish the three damaged reactors, as well as the plant’s No. 4 unit, but that is expected to take 40 years and will require use of new technologies.
New danger – the weather
Meanwhile, Fukushima now faces yet another impending typhoon season, which could result in even more damage and contamination at the site.
Already this season Typhoon Guchol has hit Japan, which led to warnings of floods and landslides from the Japan Meteorological Agency.
Typhoons are common to Japan this time of year so that part is nothing new. But given the exposure and vulnerability of the Fukushima Daichai plant, the risk of a violent storm causing even more calamity is real.
A major tornado also struck in the latter part of June, killing a teenage boy, injuring 50 others and destroying houses and property.
Scientists are particularly worried about twisters hitting the damaged plant.
“Uranium spent fuel pools of No. 3 and No. 4 reactors are currently naked,” Kazuhiko Kudo, a research professor of nuclear engineering at Kyushu University, said June 5. “A tornado with winds of 100 meters per second like the one that hit Tsukuba could suck up the pool water,” exposing the fuel rods, he said.
Sources:
http://uk.news.yahoo.com
http://www.rttnews.com
http://fuelfix.com