25th Annual Report by the Diablo Canyon Independent Safety Committee, July 1, 2014—June 30, 2015
Preface | Executive Summary
Volume I TOC | Volume II TOC | PG&E Response | Contact the DCISC
25th Annual Report, Volume I, Section 4.7, Emergency Preparedness
4.7.1 Overview and Previous Activities
An Emergency Preparedness Program has been in-place since the beginning of the nuclear power industry; however, the accident at Three Mile Island brought substantial changes. Prior to Three Mile Island, Emergency Operating Procedures (EOPs) were primarily event-based, requiring the operator to know which event was taking place. Afterward, the EOPs became symptom-based, making it easier for the operator to decide what actions to take. The five major facilities used in an actual emergency situation (and used for practice in an emergency drill) include (1) the Control Room (simulator in practice) where operators respond to the accident (2) the station Technical Support Center (TSC) where engineering, computer, radiological assessment, NRC, and operations, as well as documents and procedures, are located, (3) the offsite Emergency Operations Facility (EOF) where the Recovery Manager and administrative and technical staff are located, (4) a station Operations Support Center (OSC) that provides a location to stage and dispatch operations, maintenance, firefighting, and radiation protection personnel, and (5) the Joint Information Center (JIC) where DCPP and San Luis Obispo County interface with the media.
The DCISC reviews Emergency Preparedness at DCPP on a regular basis. Past Committee activities have included observations and reviews of drills and full, graded emergency exercises each year and related issues from the observations.
During the previous reporting period, the DCISC reviewed the following specific items:
- Social Media in the DCPP Emergency Response Organization
- Cooperative Efforts Between DCPP and the California Department of Forestry and Fire Protection (CalFire)
- San Luis Obispo County Emergency Precautionary Actions and Use of Social Media
- Observe Evaluated Hostile Action Based Emergency Exercise
The DCISC concluded the following during the previous reporting period:
DCPP appeared to have made considerable progress in enhancing the capabilities of its Fire Department, both in preparation and in equipment, to respond to a station fire and/or nuclear emergency. Communications and cooperation between DCPP’s Fire Department and CalFire (and other nuclear plants) also appeared to have strengthened. The San Luis Obispo County Office of Emergency Services uses of Precautionary Actions and social media appeared appropriate. During an evaluated hostile action based emergency exercise the Emergency Response Organization (ERO) successfully assessed plant damage conditions that were well outside the plant’s design basis, effectively prioritized repair activities, and executed time-critical actions to successfully stabilize the plant.
4.7.2 Current Period Activities
The DCISC reviewed the following in DCPP’s Emergency Preparedness (EP) Program during the current period (2014–2015):
- MIDAS (Meteorological Information and Doses Assessment System
- Emergency Preparedness NRC Violation
MIDAS (Meteorological Information and Dose Assessment System) (Volume II, Exhibit D.2, Section 3.1 and Exhibit D.8, Section 3.3)
For practice emergency exercises or actual accidents involving radioactive material releases, radioactive dose assessment begins in the Control Room (CR) (or Control Room Simulator for practice exercises). Operators in the CR use a program named “EPR2net” to make initial calculations of offsite radiological consequences as described in DCPP Procedure EP R-2, “Release of Airborne Radioactive Materials Initial Assessment.” The backup for this process is a manual calculation of radiological consequences using templates and pre-determined formulas. When the Unified Dose Assessment Center (UDAC), a joint DCPP and San Luis Obispo (SLO) County team, is activated in a practice exercise or an actual emergency, they assume the duty of calculating offsite radiological consequences using EARS (Emergency Assessment Response System) and MIDAS.
MIDAS is used by PG&E to predict the path and magnitude of radiation releases to the surrounding environment caused by an accident at the plant, such that protective action (sheltering, evacuation, etc.) recommendations can be made to protect the public. Inputs to MIDAS include the concentration and height of radioactive releases at the plant from EARS and wind and temperature data from up to seven meteorological towers and several SODAR (Sonic Detection and Ranging) units. The predictions are corroborated by data from roving Field Monitoring Teams and by nine Pressurized Ionization Chambers (PIC radiation detectors) at fixed locations.
DCPP originally used only the initial version of MIDAS in the early 1990s with one meteorological tower for wind speed and direction and elevation temperature data. Now DCPP uses the second revision of MIDAS along with EARS with seven meteorological towers and several SODAR (Sonic Detection and Ranging) units for more accurate weather data. Beginning December 2014, DCPP plans to implement the latest version of MIDAS as a standalone without EARS. The new release of MIDAS is capable of predicting off-site transport for multi-point releases (e.g., simultaneous accidents in both units).
The purpose of the MIDAS second revision upgrade was to enhance the capability of PG&E and the County for making appropriate Protective Action Recommendations (PARs) and decisions. Such decisions relate to the need to evacuate or shelter the population in various geographic sectors in the vicinity of DCPP in the event of an unplanned radiological release from the site. Typically, the most significant radioisotope initially from a radiological accident is Iodine-131, which may be released in the form of small aerosol particles from fuel damaged in a severe accident, and can be ingested through breathing or eating contaminated food and then concentrated in the thyroid gland. The closest population area to the plant at about six miles is Port San Luis with approximately 180 people. In emergency exercises, the County frequently decides to evacuate this area early in in the exercise because of the area’s location and frequent winds in its direction (actual evacuation does not occur, it is only simulated). Historically, during exercises the County has issued orders to evacuate selected population zones and schools well before the joint PG&E/County Unified Dose Assessment Center (UDAC) has recommended them.
The DCISC observed an example of the EPR2net application and an example of the latest MIDAS application on the computer. The models successfully generated and predicted radiological consequences for selected postulated radiological releases from the plant.
When the Unified Dose Assessment Center (UDAC), a joint DCPP and San Luis Obispo (SLO) County team, is activated in a practice exercise or an actual emergency, the UDAC personnel assume the responsibility of calculating offsite radiological consequences originally using EARS (Emergency Assessment Response System) and MIDAS. Now, the new MIDAS replaces EARS. Similarly, MIDAS replaces RASCAL (Radiological Assessment System for Consequence Analysis) previously used by San Luis Obispo County.
DCPP appears to have implemented the third version of MIDAS (Meteorological Information and Dose Assessment System) for predicting the magnitude and path of radioactive plumes from the plant in the event of an emergency. This version will provide more accuracy and versatility than the previous version.
Emergency Preparedness NRC Violation (Volume I, Section 3.2.2 and Volume II, Exhibit B.15)
DCPP received a Safety Significance Level III (White) violation from NRC for failure to obtain prior approval for a change, which decreased the effectiveness of the Emergency Plan (See Section 3.2.2). This is a White, or low-to-moderate level of safety significance. Specifically, on November 4, 2005, without approval from the NRC, Diablo Canyon Power Plant staff removed instructions in emergency plan implementing procedures for making protective action recommendations for members of the public on the ocean within the 10-mile Emergency Planning Zone, reducing the plan’s effectiveness. DCPP’s corrective actions included adding an emergency preparedness supervisor position for additional oversight; adding metrics to monitor program health; strengthening procedure instructions, training, and qualifications for performing change evaluations; and adding a protective action recommendation bases document to the site emergency plan. In addition, DCPP initiated an Emergency Preparedness Licensing Basis Verification Project to reassess all changes to the emergency plan since its original approval by the NRC.
DCPP originally developed PARs directly from the protective action zones, but because adjacent ocean areas were not explicitly identified as a protective action zone, there was no range of protective actions for members of the public in the plume exposure pathway emergency planning zone. As a result of the 2005 change, the NRC determined that the DCPP’s emergency plan implementing procedures no longer contained guidance or requirements for developing and communicating PARs for areas of the Pacific Ocean that lie within the nominal 10-mile emergency planning zone. The November 4, 2005, revision to Diablo Canyon Power Plant EP G-3 removed the sector-to-zone conversion table. The zones were not revised to include the ocean and until corrected in February 13, 2014, DCPP did not have a procedure that ensured that PARs would be made for the ocean. The 2005 revision to the plan removed all procedural direction to provide PARs for affected areas over the ocean within 10 miles of the plant. DCPP did not request NRC approval for this change; therefore, the NRC was not given the opportunity to review these changes to its emergency plan. This caused DCPP’s procedures to be in noncompliance with its emergency plan and NRC’s planning standard.
DCPP believed that the county had adequate guidance in its procedures to implement necessary protective actions. The NRC determined that development of PARs is a regulatory requirement of the licensee, and could not be met by assuming that responsible offsite response organizations would make the correct decision absent any recommendation from the licensee. NRC concluded that this finding represents a degradation of the licensee’s risk-significant planning standard function. The required planning standard function was degraded because the licensee’s procedures did not direct the licensee to issue appropriate PARs to cover affected areas over the ocean within 5 to 10 miles of the site. The planning standard function was degraded, rather than lost, because default procedural actions of local governments would have resulted in effective protective actions for affected areas within 5 miles of the site.
4.7.3 Conclusions and Recommendations
- DCPP appeared to have successfully implemented the second and third versions of the Meteorological Information and Dose Assessment System (MIDAS), utilizing seven meteorological towers and several sonic detection and ranging (SODAR) units, which provides more accurate offsite radiation release consequence predictions. The NRC Level III violation on Emergency Preparedness is White, or low-to-moderate level of safety significance. DCPP addressed the violation with appropriate corrective actions