Media playback is unsupported on your device Media caption Rupert Wingfield-Hayes reports that the change in severity level is regarded as "significant" 
 
 Japan's nuclear agency has upgraded the severity level of a radioactive water leak at the Fukushima plant from one to three on an international scale. 
 
 Highly radioactive water was found to be leaking from a storage tank into the ground at the plant on Monday. 
 
 It was first classified as a level one incident on the International Nuclear and Radiological Event Scale (Ines). 
 
 But Japan's Nuclear Regulation Authority proposes elevating it to level three on the seven-point scale. 
 
 Media playback is unsupported on your device Media caption Joanna Gosling explains where the leaks are coming from 
 
 Japanese reports say it is a provisional move that had to be confirmed with the IAEA, the UN's nuclear agency. 
 
 This week is the first time that Japan has declared an event on the Ines scale since the 2011 earthquake and tsunami. 
 
 The move was announced in a document on the agency's website and was subsequently approved at a weekly meeting of the regulatory body. 
 
 Shares of plant operator Tokyo Electric Power Company (Tepco) fell as much as 13% to 537 yen as investors worried about the impact of the development. 
 
 'Five-year dose' 
 
 Image caption Workers discovered the water was leaking from a tank on Monday 
 
 The March 2011 tsunami knocked out cooling systems to the reactors at the plant, three of which melted down. 
 
 Water is now being pumped in to cool the reactors but this means that a large amount of contaminated water has to be stored on site. 
 
 What is Ines? Overseen by the UN nuclear agency, the IAEA 
 
 Events are classified at seven levels: Levels 1-3 are "incidents" and Levels 4-7 "accidents" 
 
 In order, the levels are classified as: anomaly; incident; serious incident; accident with local consequences; accident with wider consequences; serious accident; major accident 
 
 To date, two incidents have been classified as level 7 - Chernobyl and Fukushima 
 
 The severity of an event is about 10 times greater for each increase in level on the scale Source: IAEA website 
 
 There have been leaks of water in the past but this one is being seen as the most serious to date, because of the volume - 300 tonnes of radioactive water, according to Tepco - and high levels of radioactivity in the water. 
 
 Japan's Nuclear Regulation Authority (NRA) said it feared the disaster was "in some respects" beyond Tepco's ability to cope. 
 
 "We should assume that what has happened once could happen again, and prepare for more," watchdog chairman Shunichi Tanaka told a news conference. "We are in a situation where there is no time to waste." 
 
 He said Tepco had failed to spot the leak for days - maybe weeks - despite patrols that are supposed to check each storage tank twice every day. Workers had also left a tap open in the safety barrier that surrounds the base of the leaking storage tank. 
 
 That had allowed highly toxic water to trickle away into the ground. Latest reports from the plant suggest some of it may already have reached the nearby Pacific Ocean. 
 
 The BBC's Rupert Wingfield-Hayes in Tokyo says it all adds to the impression that the clean-up operation is riddled with complacency and incompetence. 
 
 A puddle of the contaminated water was emitting 100 millisieverts an hour of radiation, Kyodo news agency said earlier this week. 
 
 Masayuki Ono, general manager of Tepco, told Reuters news agency: "One hundred millisieverts per hour is equivalent to the limit for accumulated exposure over five years for nuclear workers; so it can be said that we found a radiation level strong enough to give someone a five-year dose of radiation within one hour." 
 
 Teams of workers at the plant have surrounded the leaking tank with sandbags and have been attempting to suck up large puddles of radioactive water. 
 
 But our correspondent says it is a difficult and dangerous job. The water is so radioactive that teams must be constantly rotated and it is clear that most of the toxic water has already disappeared into the ground. 
 
 Under the Ines, events have seven categories starting with Level 0 ("without safety significance") and Levels 1-3 denoting "incidents" while Levels 4-7 denote "accidents". 
 
 The triple meltdown at Fukushima two years ago was classed as a level 7 incident, one of only two nuclear events ever rated that highly - along with the 1986 Chernobyl disaster in the former Soviet Union. ||||| TOKYO Japan's nuclear crisis escalated to its worst level since a massive earthquake and tsunami crippled the Fukushima plant more than two years ago, with the country's nuclear watchdog saying it feared more storage tanks were leaking contaminated water. 
 
 The U.N.'s International Atomic Energy Agency (IAEA) said on Wednesday it viewed the situation at Fukushima "seriously" and was ready to help if called upon, while nearby China said it was "shocked" to hear contaminated water was still leaking from the plant, and urged Japan to provide information "in a timely, thorough and accurate way". 
 
 "We hope the Japanese side can earnestly take effective steps to put an end to the negative impact of the after-effects of the Fukushima nuclear accident," China's Foreign Ministry said in a statement faxed to Reuters in Beijing. 
 
 Japan's Chief Cabinet Secretary Yoshihide Suga called the situation "deplorable", and the Nuclear Regulation Authority (NRA) said it feared the disaster - the worst nuclear accident since Chernobyl a quarter of a century earlier - was "in some respects" beyond the plant operator's ability to cope. 
 
 The plant's operator, Tokyo Electric Power Co, or Tepco, has been criticized for its failure to prepare for the disaster and has since been accused of covering up the extent of the problems at the plant. After months of denial, Tepco recently admitted the plant was leaking contaminated water into the Pacific Ocean from trenches between the reactor buildings and the shoreline. 
 
 It said on Tuesday that contaminated water with dangerously high levels of radiation was leaking from a storage tank - the most serious problem in a series of recent mishaps, including power outages, contaminated workers and other leaks. 
 
 The NRA said it was worried about leakage from other similar tanks that were built hastily to store water washed over melted reactors at the station to keep them cool. Water in the latest leak is so contaminated that a person standing close to it for an hour would receive five times the annual recommended limit for nuclear workers. 
 
 A spokesman for the NRA said the agency plans to upgrade the severity of the crisis from a Level 1 "anomaly" to a Level 3 "serious incident" on an international scale for radiological releases. An upgrade would be the first time Japan has issued a warning on the International Nuclear Event Scale (INES) since the three reactor meltdowns at Fukushima in March 2011. Explosions then led to a loss of power and cooling, triggering a maximum INES Level 7 at the plant. 
 
 "HAUNTED HOUSE" 
 
 NRA Chairman Shunichi Tanaka likened the stricken nuclear plant to a house of horrors at an amusement park. "I don't know if describing it this way is appropriate, but it's like a haunted house and, as I've said, mishaps keep happening one after the other," he told reporters. "We have to look into how we can reduce the risks and how to prevent it from becoming a fatal or serious incident." 
 
 He said the NRA would consult with the IAEA about whether it was appropriate to assign a rating to the leakage at the plant. 
 
 "Japanese authorities continue to provide the Agency with information on the situation at the plant, and Agency experts are following the issue closely," Gill Tudor, spokesperson at the Vienna-based IAEA, said in an e-mailed statement. 
 
 "The IAEA views this matter seriously and remains ready to provide assistance on request." 
 
 Each one-step INES increase represents a 10-fold increase in severity, according to a factsheet on the IAEA website. (www.iaea.org/) A Level 3 rating is assigned when there is exposure of more than 10 times the limit for workers, according to the factsheet. 
 
 In an emailed comment, Andrew Sherry, director of the Dalton Nuclear Institute at the University of Manchester, said: "Though serious, this leak is a long way from the Level 7 incident we were facing in 2011. The approach taken by Tepco to drain the tank, pump leaked water to temporary storage, and protect the drainage of contaminated water to ground water, is entirely sensible." 
 
 "This incident highlights the need for an inspection program for these many hundreds of storage tanks, and the need to consider replacing bolted or sealed storage tanks, which were relatively quick to build, with a more robust welded design." 
 
 South Korea's Asiana Airlines Inc said it would cancel charter flights between Seoul and Fukushima city in October due to public concerns over the radioactive water leaks. 
 
 The city, around 60 kms (37 miles) from the nuclear facility and with a population of some 284,000, is a popular destination for golfers and tourists visiting nearby local hot springs and lakes. 
 
 (With additional reporting by Kentaro Hamada, Olivier Fabre and Chris Meyers in TOKYO, Ben Blanchard in BEIJING, Kim Miyoung in SEOUL, Fredrik Dahl in VIENNA and Kate Kelland in LONDON; Writing by Aaron Sheldrick; Editing by Edmund Klamann, Paul Tait and Ian Geoghegan) ||||| INES 
 
 The International Nuclear and Radiological Event Scale 
 
 
 
 
 
 What is INES? 
 
 INES is a tool for promptly and consistently communicating to the public the safety significance of events associated with sources of ionizing radiation. 
 
 What is the purpose of INES? 
 
 The primary purpose of INES is to facilitate communication and understanding between the technical community, the media and the public on the safety significance of events. The aim is to keep the public as well as nuclear authorities accurately informed on the occurrence and consequences of reported events. 
 
 Scope of INES 
 
 The INES scale applies to any event associated with the use, storage and transport of radioactive material and radiation sources, whether or not the event occurs at a facility; this includes events involving the loss or theft of radioactive sources or packages and the discovery of orphan sources, such as sources being discovered in scrap metal. 
 
 INES is also used for the rating of events resulting in actual exposure of workers and the public in medical, research and educational institutions. 
 
 The scale does not cover the actual or potential consequences for patients exposed as part of a medical procedure. 
 
 INES is intended for use in civil, i.e. non-military applications and only relates to the safety aspects of an event. 
 
 It is not appropriate to use INES to assess or to compare safety performance between facilities, organizations or countries. 
 
 Description of INES 
 
 INES uses a numerical rating to explain the significance of events associated with sources of ionizing radiation. 
 
 Events are rated at seven levels: Levels 1–3 are “incidents” and Levels 4–7 “accidents”. The scale is designed such that the severity of an event is approximately ten times greater for each increase in level of the scale. These levels consider 3 areas of impact: 
 
 People and the environment 
 
 Radiological barriers and control 
 
 Defense in depth 
 
 Events without safety significance are rated as Below Scale/Level 0. Events that have no safety relevance with respect to radiation or nuclear safety are not rated on the scale. 
 
 INES Rating Interactive Learning Tool 
 
 The INES Rating Interactive Learning Tool (INES-RILT) is a tool aimed to assist users in understanding and applying the INES methodology. 
 
 The tool follows the structure of the INES User's Manual which facilitates the task of rating the safety significance of events using the scale. The INES User’s Manual includes additional guidance and clarification, as well as provides examples and comments on the ongoing use of INES. 
 
 The tool leads the user through the description of the scale, through detailed definitions of the levels and through criteria for each level in regard to the impact of the events to people and the environment, radiological barriers and controls at facilities, and the impact on the defence in depth areas. 
 
 The purpose of INES-RILT is to: 
 
 Provide initial on-line training to participants unable to attend training course 
 
 Provide a refresher course for those already trained 
 
 Although the interactive tool is primarily for the use of those already acquainted with INES, senior management of the operating organisations and regulatory bodies may also find the tool to be practical and user friendly in its presentation in comparison with the more technically presented INES User's Manual. 
 
 INES Guidelines and good practices 
 
 This publication is the first to provide guidance on establishing or improving a national framework for the effective use of INES during event communication. 
 
 
 
 Participation in INES 
 
 Participation in INES is voluntary and open to all IAEA Member States. Member States are invited to officially designate INES National Officers via official channels. INES National Officers represent their countries in the biennial INES technical meetings and participate in discussions and decisions on the application of the scale. 
 
 Background 
 
 INES was developed in 1990 by international experts convened jointly by the IAEA and the Nuclear Energy Agency of the Organization for Economic Co-operation and Development (OECD/NEA). Initially the scale was applied to classify events at nuclear power plants, then extended and adapted to enable it to be applied to all installations associated with the civil nuclear industry. More recently, it has been extended and adapted further to meet the growing need for communication of the significance of all events associated with the use, storage and transport of radioactive material and radiation sources. 
 
 For further information please contact ||||| The Japanese nuclear watchdog on Wednesday said they are taking the leakage of highly radioactive water at the crippled Fukushima nuclear power plant seriously, and proposed raising the rating to describe it from "an anomaly" to a "serious incident." 
 
 This Aug. 20, 2013 aerial photo shows the Fukushima Dai-ichi nuclear plant at Okuma in Fukushima prefecture, northern Japan. The Japanese nuclear watchdog proposed Wednesday to define a fresh leakage... (Associated Press) 
 
 In this Tuesday, Aug. 20, 2013 aerial photo, workers stand on storage tanks at the Fukushima Dai-ichi nuclear plant at Okuma in Fukushima prefecture, northern Japan. The Japanese nuclear watchdog proposed... (Associated Press) 
 
 This Tuesday, Aug. 20, 2013 aerial photo shows the Fukushima Dai-ichi nuclear plant at Okuma in Fukushima prefecture, northern Japan. The Japanese nuclear watchdog proposed Wednesday to define a fresh... (Associated Press) 
 
 The operator of the plant said about 300 tons (300,000 liters, 80,000 gallons) of contaminated water has leaked from one of hundreds of steel tanks around the wrecked Fukushima Dai-ichi plant. Tokyo Electric Power Co. hasn't figured out how or where the water leaked, but suspects it did so through a seam on the tank. 
 
 The leak, the fifth since last year involving tanks of the same design, also raised concerns that this could be the beginning a new disaster _ contaminated water leaking from storage tanks one after another. 
 
 "That's what we fear the most. We must remain alert. We should assume that what has happened once could happen again, and prepare for more," watchdog chairman Shunichi Tanaka told a news conference. "We are at a situation where there is no time to waste." 
 
 The watchdog proposed at a weekly meeting Wednesday to raise the rating of the leak to level 3 from an earlier level 1 on an International Nuclear and Radiological event scale of eight. The watchdog, however, plans to consult with the U.N. nuclear regulatory agency over whether it is appropriate to use the INES evaluation scale on the already wrecked Fukushima plant. 
 
 The watchdog urged TEPCO to step up monitoring for leaks and take precautionary measures. 
 
 During the meeting, officials also revealed that plant workers apparently have overlooked several signs of leaks, suggesting that their twice-daily patrols were largely just a walk. They have not monitored water levels inside tanks, obviously missed a puddle forming at the bottom of the tank earlier, and kept open a valve on the anti-leakage barrier around the tanks. 
 
 TEPCO spokesman Masayuki Ono said the leaked water seeped into the ground after largely escaping piles of sandbags added to a concrete barrier around the tank. He said that because the tank is about 500 meters (1,650 feet) from the coastline, the leak does not pose an immediate threat to the sea. 
 
 But watchdog officials have cautioned that water could reach the sea via a drain gutter, urging the plant to step up water sampling. 
 
 Four other tanks of the same design have had similar leaks since last year. The incidents have shaken confidence in the reliability of hundreds of tanks that are crucial for storing water that has been funneled into the broken reactors to keep melted radioactive fuel cool. 
 
 The plant suffered multiple meltdowns following a massive earthquake and tsunami in March 2011 _ a level 7 "major accident," the highest on the INES rating and the worst since Chernobyl in 1986. 
 
 About 350 of some 1,000 steel tanks built across the plant complex containing nearly 300,000 tons (300 million liters, 80 million gallons) of partially treated contaminated water are less-durable ones with rubber seams. 
 
 TEPCO says the tanks that have leaked use rubber seams that were intended to last about five years. Ono said TEPCO plans to build additional tanks with welded seams that are more watertight, but will still have to rely on ones with rubber seams. 
 
 Figuring out what to do with the radioactive water is among the most pressing issues affecting the cleanup process, which is expected to take decades. 
 
 "The growing contaminated water has been one of our biggest concerns since the March 11 accident," said Zengo Aizawa, TEPCO's executive vice president. "The contaminated water remains a problem that could lead to a crisis." 
 
 The leaked water's radiation level, measured about 50 centimeters (2 feet) above the puddle, was about 100 millisieverts per hour _ the maximum cumulative exposure allowed for plant workers over five years, Ono said. 
 
 Contaminated water that TEPCO has been unable to contain continues to enter the Pacific Ocean at a rate of hundreds of tons per day. Much of that is ground water that has mixed with untreated radioactive water at the plant. 
 
 Workers were pumping out the radioactive puddle on the plant and the remaining water in the tank and will transfer it to other containers. By Tuesday afternoon they had captured only about 4 tons (4,000 liters, 1,000 gallons), Ono said.
– With Fukushima's radioactive leak now leakier, Japan's nuclear agency plans to up the alert level of the problem from a one to a three, reports the BBC—that's from an "anomaly" to a "serious incident," per the UN's International Nuclear and Radiological Event Scale. For some perspective, the 2011 meltdown was a level seven, or a "major accident." Still, if the UN's nuclear agency OKs the upgrade, this would be the first time Japan has issued a warning since the original meltdown, notes Reuters. Since the new leak was found, teams have been surrounding the affected tank with sandbags and trying to vacuum up puddles of radioactive water. But most of the water has already been absorbed into the ground, reports the BBC, and the chairman of the Japanese agency fears more tanks will follow suit soon. "We should assume that what has happened once could happen again, and prepare for more," he says, per the AP. "We are at a situation where there is no time to waste."