Standards (rules) for Incident Informing and Public Notification, and its Procedures for Higashidoori Nuclear Power Station (NPS)

1. Introduction

In this article, we describe standards (rules) for incident informing and public notification, and its procedures to inform an incident at Higashidoori Nuclear Power Station (NPS) to the outside.

Higashidoori NPS of Tohoku Electric Power Company (EPCO) is located at Higashidoori village in the northeast area of Aomori prefecture in Japan, and Higashidoori Unit 1 (BWR5 1100MWe) started the commissioning test in Dec.2004, and then started the commercial operation in Dec.2005. Prior to the commissioning test, the local governments (Aomori prefecture and Higashidoori village) and Tohoku EPCO have set standards for informing the local governments and releasing information about certain incidents at Higashidoori NPS to the public in order to convey those information smoothly and appropriately.

As to the standards, the local governments and Tohoku EPCO set the classification of incidents in terms of its importance, namely class A,B,C and the other (severity less than C), and have determined the way of informing the local governments about those incidents and releasing information to the public based on the class.

Class A information is the one that must be informed local governments without delay, even when at night or on a holiday, and Class A is further categorized into three items as follows.

1. Incidents to be informed in accordance with the safety agreement between local governments and Tohoku EPCO
   These incidents include what the central government defines under the national law, such as a fire incident and etc.


2. Incidents likely to have an impact on the public concerns
   These incidents include nuclear facility damages due to natural disaster like an earthquake and a typhoon.


3. Incidents similar to items a. and b. in the above but in less urgent situation
   These incidents include a minor malfunction of safety equipment which do not correspond to incidents defined in the safety agreement.

2.1.2 Class B information - important incident information

In terms of the timing to inform the local governments, Class B information is in principle almost the same as Class A information. The plant personnel must inform the local governments of an incident occurrence in during the daytime even if it happens on a holiday, but for the local governments, it can be done promptly by the next morning when it happens at night.

Incidents categorized in Class B information could be turned out to be Class A information depending on how the incident is developed.

2.1.3 Class C information - minor incident information

Class C information is in principle to be informed to the local governments within working hours in a business day. It includes minor irregularity, such as slight water leakage and so on.

2.2 Standards for releasing incident information to the public

2.2.1 Class A information - most important incident information

When an incident categorized in Class A happens, the plant personnel in principle must make it known to media organizations and post it on the company’s website immediately, even if it happens on a holiday or at night.

Even in the case of less urgent situation in Class A, the same procedure applies without delay, but if it happens at night, these duties can be done by the next morning (even if on a holiday).

2.2.2 Class B information - Important incident information

When an incident in Class B happens, the plant personnel in principle must make it known to the public over the company’s website by the next afternoon. If the next day is a holiday, posting on the website can be done on the next business day (just posting on the website, no press release).

2.2.3 Class C information - minor incident information

When an incident categorized in Class C happens, releasing incident information to the public is the same way as the Class B incident.

2.3 Standards for releasing information of more minor incidents in the other class (severity level below Class C)

For this category, we have standards for releasing information to the public as follows.

2.3.1 The information of irregularity matter (except for minor irregularity) due to equipment malfunction

This is provided to the local governments and is also posted on the company's website on the next business day.

2.3.2 The information of minor irregularity matter due to equipment malfunction

This is provided to the local governments and is also posted on the company's website on monthly basis.

3. The informing system at Higashidoori NPS

When an incident such as equipment malfunction happens at Higashidoori NPS, the plant site personnel need to judge immediately which class the incident should be categorized in accordance with the informing rule, and then inform the central government, the local governments and other related organizations about the incident. To expedite informing of the incident, we have striven to implement a PC-based emergency information system, to establish an internal informing business unit, and to carry out periodical internal information trainings.

3.1 The PC-based emergency information system

In order to inform the occurrence of an incident to the central, local governments and so forth, we have installed the PC-based emergency information system in three locations, the emergency headquarters in the in-site office, the main control room and the employee dormitory nearby NPS. When an incident occurs, the plant personnel input information into the emergency information system to process the report, and then fax the report to the central government, the local governments, etc. The fax information is transmitted all together over the lease line or the NTT (domestic carrier) line by clicking the transmission button on the display terminal of the emergency information system. After faxing, the plant personnel make telephone call to explain the incident in detail to the central government, the local governments, etc (see Fig.1, 2).

Fig.1 Frame of the emergency information system

Fig.2 Terminal of the emergency information system

The PC-based emergency information system provides two separate systems, one for a fire and the other for an incident. In the case of a fire, it is crucial to take a prompt action to inform. Therefore a shift supervisor in principle at the main control room makes a telephone call to the local fire station and faxes the first report to the central government, the local governments, etc. by using the emergency information equipment for a fire.

To alleviate workload for a shift supervisor in terms of fire informing procedure, the emergency information equipment for a fire is designed in a concept to minimize input data by using the touch panel for selecting input items.

In the case of an incident other than a fire, the plant personnel in principle at the emergency headquarters or the plant employees staying in the dormitory will fax the report to the central, local governments, etc. over the emergency information equipment.

3.2 Internal informing business unit

In order to inform an incident promptly to the outside, the plant personnel has been arranged as follows.

3.2.1 In the daytime on a business day

When an incident occurs, the emergency headquarters is set up in the in-site office immediately, and the plant manager assigns specific tasks to the information control team, public and regional relations team, radiation safety team, maintenance team, and operation management team. The specific assignment includes informing governments, releasing information to the public, restoring equipment and so on. Informing the central and local governments is carried out at the emergency headquarters of NPS in the daytime on a business day.

3.2.2 During the night on a business day

Some plant duty personnel, who live in the employee dormitory nearby and are in the managerial posts, are designated as initial informer to the outside on a daily rotating basis.

3.2.3 On holidays

Some plant duty personnel are designated to stay at the in-site office in the daytime, and also to stay at the in-site accommodation facility during the night.

4. Occurrence of incidents at Higashidoori NPS

At Higashidoori NPS, there has been no incident that must be reported under the law to the central government since the beginning of the commissioning test in Dec. 2004, but there has been 13 incidents that must be informed in accordance with standards for informing and releasing between the local governments and Tohoku EPCO.

Among 13 incidents occurred, 3 cases were caused by equipment malfunction, 1 case was caused by fire, 5 cases were caused by radioactive water leakage in the radiation control area, 1 case was caused by nonradioactive water leakage in the radiation control area, 1 case was caused by irregular variation in valid operation monitoring data and 2 cases were caused by radioactive material contamination to human body (see Table 1).

In each case, we (Tohoku EPCO) have been informing incidents promptly and appropriately to the central government and local governments in accordance with the standards set between the local governments and Tohoku EPCO. The duties are carried out by the emergency information system and the plant personnel have been trained periodically for smooth handling of the incident informing.