Personnel involved in the accident response at the Fukushima Daiichi nuclear plant were stationed at a number of locations, including in
• The main control rooms (MCRs) at the plant,
• An onsite emergency response center at the plant (onsite ERC),
• An offsite ERC established at TEPCO headquarters in Tokyo (headquarters ERC), or
• An offsite ERC located about 5 km from the plant (Offsite Center [OFC])
The functions of these organizations are described briefly in this appendix.
Personnel in the MCRs are responsible for operating the reactors during both normal and off-normal conditions. The Fukushima Daiichi nuclear plant has three MCRs, one each for Units 1 and 2, 3 and 4, and 5 and 6. There are two physically separated sets of independent controls for each reactor within each MCR.
Each MCR has one operating crew that is responsible for the two reactors being operated. During a normal shift the crew would consist of the following staff (INPO, 2011):
• Shift supervisor,
• Assistant shift supervisor,
• Two senior operators,
• Assistant senior operator,
• Two main shift operators, and
• Four auxiliary operators.
Shift supervisors in the MCRs (Figure D.1) are responsible for making reactor control and operation decisions in the event of an accident in accordance with the plant’s emergency procedures. However, under certain circumstances, including for actions requiring the cooperation of other control rooms or that are expected to have large impact on reactor
behavior, the shift supervisors are required to ask the onsite ERC for advice and direction.
FIGURE D.1 Breakdown of responsibilities for operational staff at the Fukushima Daiichi nuclear plant. Details below the Operations Department General Manager level are shown only for Units 1 and 2. SOURCE: INPO (2011). Courtesy of the Institute of Nuclear Power Operations.
At the time of the March 11, 2011, accident, the MCR crews were staffed as follows (INPO, 2011):
• The MCR for Units 1 and 2 had 11 operators and 1 trainee.
• The MCR for Units 3 and 4 had 8 operators and 1 trainee. The staffing was reduced in Unit 4 because it was in a maintenance outage.
Immediately after the earthquake, the crews then working at the MCRs were responsible for operating the reactors. Some members of other crews who were off duty at the time of the earthquake went to their control rooms to assist. Other members of those crews stayed in the ERC until it was time to relieve those on duty.
The onsite ERC was housed in a seismically isolated building designed to withstand earthquakes and equipped with backup power and filtered ventilation. The building was one of the few administrative buildings at the plant that survived the earthquake and tsunami. The onsite ERC played a crucial role in coordinating and managing onsite response activities.
The onsite ERC was responsible for providing advice and direction to the MCR shift supervisor and crew. Key decision makers were seated around a large table in the middle of the ERC; these included
• Site superintendent, who serves as the emergency director and is in charge of the onsite ERC after a severe accident occurs;
• Unit superintendents;
• Deputy directors;
• Reactor chief engineers;
• Section chiefs of 12 function teams: communication, intelligence, public relations, health physics, engineering, recovery, operation, infrastructure, medical treatment, general affairs, guard guidance, and the procurement teams. An in-house firefighting team was organized under the recovery team (Investigation Committee, 2011, p. 93).
Members of each function team were stationed in booths behind their respective section chiefs to enable oral communications. When a function team obtained information that needed to be shared with all staff in the ERC they reported it to their section chief, who then announced it via microphone so that everyone in the room could hear it.
When a decision was made by the site superintendent or others at the main table or information was provided from the headquarters ERC (described in the next section) through a teleconference system, the leader of the relevant team communicated it to his team members. Members of the headquarters ERC are able to monitor discussions made at the main table of the onsite ERC, ask questions, and give advice via a teleconference system.
An emergency response center was also established at the TEPCO headquarters in Tokyo. According to the Fukushima Daiichi NPS Nuclear Emergency Prevention Action Plan, the role of the headquarters ERC is to support the onsite ERC. The TEPCO president is chief of the headquarters ERC.
As part of its support function, the headquarters ERC is supposed to transmit information from the onsite ERC to the Ministry of Economy, Trade and Industry (METI) and to the Nuclear Disaster Response Headquarters at the Official Residence (i.e., prime minister’s residence). The OFC (see next section) would also send information to METI and the Nuclear Disaster Response Headquarters at the Official Residence. This arrangement would, in theory, reduce the number of direct inquiries to the onsite ERC.
The OFC is intended to coordinate TEPCO and central/local government activities. The OFC is located about 5 km from the plant. It is equipped with telephone lines, a video-conferencing system used primarily to connect to the Prime Minister’s office, and a satellite circuit with six satellite telephones (one fixed, three portable, and two vehicle-mounted). The OFC never functioned as intended during the Fukushima nuclear accident for the reasons described in the main body of Chapter 4.