Image: Roof work at the Unit 3 reactor building of the Fukushima Daiichi nuclear power plant
TEPCO  /  EPA file
Tokyo Electric Power Co. shows work being done on a roof to protect against rain and an expected typhoon at the Unit 3 reactor building of the Fukushima Daiichi nuclear power plant in northeastern Japan.
By Justin McCurry Correspondent
Christian Science Monitor
updated 7/20/2011 4:25:00 PM ET 2011-07-20T20:25:00

Even as Japan's embattled prime minister urged Japan to phase out nuclear power, engineers at the crippled Fukushima Daiichi nuclear power plant had reason for cautious optimism.

The crippled reactors, three of which went into partial meltdowns, are stable more than four months after the devastating earthquake and subsequent tsunami rocked the north, says the government and plant operator. Now the reactors appear to be on track for a cold shutdown.

Reactor No. 3
Days after Japan's government announced it would conduct "stress tests" at all of the country's atomic facilities, the plant's operator, Tokyo Electric Power (Tepco), said it would start injecting nitrogen into the No. 3 reactor – one of three that suffered meltdowns in the aftermath of the March 11 earthquake and tsunami.

That unit was the only one of the three stricken reactors that hadn't received injections of the inert gas, which lowers hydrogen levels inside the units and prevents the kind of explosions that rocked the facility four months ago.

RELATED Japan's nuclear fallout

Tepco had said that treating the reactors with nitrogen was critical to its broader aim of stabilizing them by mid-July. But the injections carry the risk of causing further radiation leaks from the reactor's containment vessel. Japan's nuclear safety agency said any leaks would not be big enough to hurt the surrounding environment.

Workers have also finally begun circulating water around the three most troublesome reactors in order to cool the melted fuel rods inside.

Next steps and more hurdles
In April, Tepco announced a self-imposed deadline of January 2012 to bring all six Fukushima reactors to a safe state known as cold shutdown. But a series of technical setbacks, notably solving the problem of how to contain and treat an estimated 120,000 tons of radioactive water, has cast doubt on the firm's ability to meet that deadline. With the reactors stabilized, tentative optimism has returned.

The water treatment system has suffered leaks, and engineers have struggled to find a way to store the contaminated water. Much of it still sits in the basements of reactor buildings.

Construction of large steel radiation covers for three units is scheduled for October, according to Tepco.

Meanwhile, concern is rising for the health of the plant's 2,902 workers – all but 373 of them contract employees brought in from outside – who are battling not only radiation but also the arrival of an early-summer heat wave. Tepco says it has stepped up radiation monitoring and is opening more on-site rest areas and providing workers with coolant vests and refrigerant packs.

If the short-term prognosis for Fukushima has improved, Japan's leaders have conceded that the cleanup and decommissioning could take much longer than expected.

This article, "Japan's nuclear crisis: Fukushima plant stability in sight?," first appeared on CSMonitor.com.

© 2012 Christian Science Monitor

Photos: After Japan's earthquake and tsunami - week 8

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  1. A radiation measuring instrument is seen next to some residents in Kawauchimura, a village within the 12- to 18-mile zone around the Fukushima Daiichi nuclear plant, on April 28. Most residents of Kawauchimura have evacuated in order to avoid the radiation, but some remain in the area of their own accord. (Koichi Kamoshida / EPA) Back to slideshow navigation
  2. A brazier heats the house of Masahiro Kazami, located within a 12-mile radius of the Fukushima Daiichi nuclear plant, April 28. (Koichi Kamoshida / EPA) Back to slideshow navigation
  3. Volunteers help clean a cemetery at Jionin temple in Ishinomaki, Miyagi prefecture, northeastern Japan, on April 29. Many volunteers poured into the disaster-hit region at the beginning of the annual Golden Week holiday. (Hiro Komae / AP) Back to slideshow navigation
  4. Japanese government adviser Toshiso Kosako is overcome with emotion during a news conference on April 29 in Tokyo announcing his resignation. The expert on radiation exposure said he could not stay on the job and allow the government to set what he called improper radiation limits for elementary schools in areas near the tsunami-damaged Fukushima nuclear plant. (AP) Back to slideshow navigation
  5. Fuel rods are seen inside the spent fuel pool of the Fukushima Daiichi nuclear plant reactor 4 on April 30. (Reuters) Back to slideshow navigation
  6. A volunteer girl from Tokyo works to clean the debris of a house in Higashimatsushima, northern Japan, on April 30. (AP) Back to slideshow navigation
  7. Farmer Tsugio Sato tends to his Japanese pear trees in Fukushima city, May 1. He said he expects to harvest the pears in October. Farmers and businesses face so-called "fuhyo higai," or damages stemming from the battered reputation of the Fukushima brand. (Hiro Komae / AP) Back to slideshow navigation
  8. Members of Japan Ground Self-Defense Force in protective gear receive radiation screening in Minamisoma in Fukushima prefecture, after searching for bodies at an area devastated by the March 11 earthquake and tsunami. (Reuters) Back to slideshow navigation
  9. Ruriko Sakuma, daughter of dairy farmer Shinji Sakuma, rubs a cow at their farm in the village of Katsurao in Fukushima prefecture on May 3. Thousands of farm animals died of hunger in the weeks following the quake. (Yoshikazu Tsuno / AFP - Getty Images) Back to slideshow navigation
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