At the end of September, Tokyo Electric Power Co. (TEPCO) filed an application for safety inspections of Units 6 and 7 at its Kashiwazaki-Kariwa Nuclear Power Station (KKNPS) in Niigata Prefecture with the Nuclear Regulation Authority (NRA), seeking the restart of the two reactors. This is the first time that an application for safety assessments of boiling water reactors (BWR) has been submitted to the nuclear watchdog.
TEPCO insists that the reactivation of the two advanced boiling water reactors (ABWRs), with an output of 1,356 MW each, would greatly contribute to the financial rehabilitation of the power utility. Niigata Prefecture Governor Hirohiko Izumida previously criticized TEPCO for attaching greater importance to business than to safety of the prefectural residents’ lives. He therefore did not approve the utility’s filing of the application at the time.
The Japanese public does not support TEPCO’s stance. The governor has maintained that the first thing the company should do is thoroughly examine the Fukushima nuclear accident from the dual viewpoints of equipment failure and human error.
Without completing a full-fledged examination of the nuclear accident, who can devise measures for the safe management of nuclear plants? Should a severe nuclear accident, like the one that occurred in Fukushima, happen again, how can the local residents prevent exposure to radiation, and how can they evacuate?
There has been strong criticism of TEPCO’s recent move to seek reactivation of the KKNPS, not only in the groups calling for Japan’s departure from nuclear power generation, but also among groups seeking the restart of nuclear power generation.
They question whether the utility has sufficient resources for reactivation of the Niigata plant amid the current plight where both disposal of the radioactive water leaking from the Fukushima plant and the clean-up operations after the nuclear accident are facing great difficulties, and the company is taking makeshift, half-measures to address these problems. The prospect of decommissioning the crippled Fukushima plant, believed to require 30 to 40 years, remains bleak. This is because the decommissioning of the Fukushima plant is an unprecedented operation that has never been experienced before.
Since the Niigata Chuetsu-oki Earthquake occurred in July 2007, residents of Niigata Prefecture have discussed the safety and resilience of the KKNPS jointly with prefectural government officials and with the help of experts critical of nuclear power generation. Of the seven nuclear reactors at the plant, Units 2, 3 and 4, are still under discussion and have been off-line since 2007.
When the Fukushima nuclear accident occurred on March 11, 2011, the four reactors at the Niigata plant that had been reactivated after the Chuetsu-oki earthquake (in order: Units 7, 6, 5, and 1) were again shut down. Under the current circumstances, the chances of restarting the reactors at the Niigata plant, including the above-mentioned four units, is very slim and the likelihood of the plant’s closure is becoming stronger.
Even if Unit 7 clears the official safety inspection, TEPCO is required to obtain consent to operate the reactor from local residents. This means that a majority of the residents of Kashiwazaki City and Kariwa Village, where the nuclear plant is located, must agree to the reactor reactivation plan in the first place, and then the mayors of the city and the village must approve the plan by reflecting the opinions of local residents. In the final stage, the Niigata Prefecture Governor must endorse the plan. The governor will make his decision based on the result of the discussions by Niigata Prefecture’s technical committee on the safe control of nuclear power plants, the committee’s consent being a prerequisite for the governor’s endorsement.
|Plumbing crack at KKNPS that occurred during the Niigata Chuetsu-oki Earthquake in July 2007. Photo by TEPCO||One-meter ground subsidence at KKNPS that occurred during the Niigata Chuetsu-oki Earthquake. (Reported in the 20 questions and answers on why KKNPS must not restart.)|
2) Unique Niigata Method
Niigata Prefecture has three technical committees that are evaluating the safety of KKNPS. The above-mentioned technical committee is comprised of 17 members and was organized in the summer of 2002, in the wake of revelations concerning TEPCO’s falsification of safety inspection reports. Under this committee, there are two subcommittees, the Subcommittee on Earthquakes and Ground Conditions (six members) and the Subcommittee into Equipment Integrity, Earthquake Resistance and Safety (eight members). These two subcommittees were set up after the 2007 Chuetsu-oki earthquake. They conduct more detailed discussions and examinations than the technical committee, to which the results of their discussions are reported. The technical committee makes a comprehensive judgment taking subcommittee reports into consideration. The governor makes his decision based on the judgment of the technical committee, and from the viewpoint of protecting the lives, safety and assets of the people of Niigata Prefecture.
An important feature of the technical committee, and especially the two subcommittees, is that they include among their members some academics who are critical of nuclear power and do not belong to the so-called ‘nuclear village’ of people in the government, academia and the power industry. There are currently no other official committees like this in Japan. This is why it is called the Niigata Method. Behind this, there seems to be a historically-accumulated, deep-seated distrust of the central government and TEPCO among the Niigata Prefectural government employees and local residents.
In Niigata Prefecture, three organizations of local residents have been waging opposition campaigns against the KKNPS since 1968. A group seeking transparency of information on KKNPS joined the movement in 2003, and in 2008, another group was organized for protecting local people’s lives and hometowns from the nuclear power plant. These two groups have been working actively and tenaciously.
KKNPS was hit hard by the Chuetsu-oki earthquake and suffered serious damage in more than 3,000 locations. Concerned about this, in August 2007 a number of scientists and engineers established a group calling for the closure of the nuclear power plant. Other experts from all parts of Japan are participating in this group, which continues to hold scientific and technological discussions on the plant from a critical point of view. The group is presenting its opinions to the Niigata Prefectural government, local residents, as well as to the national government. Even if TEPCO is eager to restart reactors at KKNPS, there is little chance of realization of this plan.
3) New NRA standards do not assure the safety of nuclear plants
TEPCO says it has applied for NRA inspections because it wished to have a third party check of the safety of the reactors. It is questionable whether NRA is truly a third-party organization, but let’s leave this issue aside here. Even if the reactor met the NRA requirements, this does not necessarily mean that the reactor’s safety was guaranteed, because the new safety rules are extremely deficient.
The most problematic point about the new NRA rules is that they do not require the plant operator to assess the plant’s location. The safety rules compiled by the former Nuclear Safety Commission (NSC) provided that the cumulative radiation exposure of local residents in the surrounding areas should be held below 250 mSv annually, even if a severe nuclear accident occurred and radioactive substances were released into the local environment. To clear this requirement, the reactors should be constructed in locations far from residential areas. The NSC rules, however, did not take the release of cesium into consideration. Only discharges of noble gases were taken into account because the meltdown of the nuclear fuel in the reactor core and the destruction of the containment vessel were not assumed at that time.
NRA Chairman Shunichi Tanaka has said that core meltdown has now actually occurred in the Fukushima nuclear plant and it is therefore evident that no nuclear power plants in Japan can meet this location requirement. NRA thus worked out a new rule that the maximum permissible amount of cesium emitted from the reactor with a filtered venting system should be held below 100 terabecquerel (TBq). Although the amount, 100 TBq (1014 Bq), is roughly one percent of the total amount of cesium discharged from the Fukushima nuclear plant, the problem is that in the calculation of radiation exposure of local residents the new rule does not include the amount of noble gases, such as iodine, xenon, krypton, that pass through the filtered venting system.
The calculation by Koichi Takitani, member of the Citizens’ Committee on Nuclear Energy, has revealed that the accumulated exposure to noble gases from Unit 6 would reach 2,300 mSv annually on the border between the plant and its surrounding areas if a major accident were to occur at the plant and 100 percent of the noble gasses passed through the filtered venting system and escaped to the area outside the plant. Should such a great amount of irradiation occur, the residents in the surrounding areas would have little option but to evacuate.
4) Will residents consent to restarts despite exposure risks?
Two years and nine months have already passed since the disastrous accident at the Fukushima nuclear plant. Yet nearly 160,000 people still continue to be sheltered in uncomfortable surroundings. How many of them will eventually be forced to give up their hopes to return to their hometowns where they were born and grew up? It is also certain that another nuclear accident will occur at sometime in the future.
During the past 30 years, a total of five reactors have had severe nuclear accidents, one at the Three Mile Island Nuclear Power Plant in the U.S., one at the Chernobyl Nuclear Power Station in the Ukraine, in the former Soviet Union, and three at the Fukushima Daiichi Nuclear Power Station. This means that a severe accident has occurred, on average, once every six years. Given this situation, the new NRA rules require nuclear plant operators to install filtered venting systems in all reactors, thereby assuming that a similar severe nuclear accident would occur again.
However, to conduct emergency venting means that the residents would be exposed to radiation. Niigata Prefecture Governor Hirohiko Izumida led the anti-nuclear disaster drill on March 23, 2013, based on the assumption that such an emergency could happen again.
In the case of KKNPS, 16,500 people are living within the 5-kilometer radius of the plant from which immediate evacuation is required if a major nuclear accident occurs, 82,000 people live within a 10-kilometer radius, and 435,000 people within a 30-kilometer radius, known as the Urgent Protective Action Planning Zone (UPZ), where plans need to be made for residents to stay indoors or evacuate safely if radiation levels exceed certain levels. 1.13 million people are living within a 50-kilometer radius of the plant,.
If all the people living within the 5-kilometer radius should evacuate immediately after a severe accident, 330 large (50-seat) buses would be necessary. But it would be impossible to deploy such a large number of buses immediately. Four hundred local residents took part in the emergency drill held on March 23, and some of them were to be taken by bus to the pre-selected evacuation area 20 kilometers away However, it was difficult for them to get onto the highway due to a traffic jam, and they had no choice but to give up the drill and eat lunch in the bus. The residents returned home in the evening. Consequently, the drill was totally unrealistic.
When the nuclear accident occurred in Fukushima, local residents living within a radius of 50 kilometers were forced to evacuate. After such bitter experiences, do the local residents really approve of the reactivation of the Niigata nuclear power plant?
5) Nuclear power plant floating on ‘cheese fondue’
|Major active faults near KKNPS
(Reported in the 20 questions and answers on why KKNPS must not restart.)
In 1968, when the plan to build KKNPS was proposed, local residents were sharply critical, citing the fragility of the land at the planned construction site, which was previously an oil-field. They staged opposition campaigns, claiming that the plan calls for construction of a nuclear plant on land as soft as tofu bean curd.
In December 2008, an official meeting to explain about the status of damage in KKNPS to local residents was held in Kariwa Village. On that occasion, Chairman Haruo Yamazaki of the Subcommittee on Earthquakes and Ground Conditions said the nuclear power plant looks as if it is floating on ‘cheese fondue,’ but added that it is technologically possible to construct a nuclear power plant on such soft land. His comment drew a loud chorus of boos and catcalls.
When the Chuetsu-oki earthquake hit Niigata, the reactor buildings were jolted by a quake nearly four times as strong as that assumed in the design standard. Since then, the buildings have suffered uneven, upward and downward displacements. The reason why this is happening is still unknown. Another major source of concern is that the resilience of the ABWR recycling pump motor casing was proved to be almost the same level as that of the design standard and the pump barely endured the Chuetsu-oki earthquake.
There is no guarantee that the Niigata Nuclear Power Plant could withstand the 7.5 magnitude earthquake that could occur when the fault at the eastern end of the sea basin off Sadogashima Island in Niigata Prefecture slips. If we wish to prevent a recurrence of the disastrous nuclear accident at Fukushima, there is no option but to decommission KKNPS.
(Yukio Yamaguchi, Co-director of CNIC)