Fatal reactor accident proves value of training

Fatal reactor accident proves value of training

Cutaway drawing, of SL-1 reactor building including control room at the lower right, National Reactor Testing Station, Idaho

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HOW CAN FIREMEN cope with fires or explosions in atomic reactors, cyclotrons or accelerators, and perform rescues at such incidents, if necessary? A mishap early this year provides valuable lessons for such emergencies.

A nuclear accident, involving a severe explosion, fatally injured three men shortly after 9:00 p.m. on January 3, 1961, at the National Reactor Testing Station near Idaho Falls, Idaho. The accident, first of its kind in the 11-year history of the Idaho Site and the first fatal accident in the history of U. S. reactor operations, occurred at the Stationary Low-Power Reactor No. 1 (SL-1)in the Army Reactor Experimental Area. The SL-1 is a prototype of a small power reactor designed for transportation by the Army to remote localities for providing electricity and space heat.

Certain events related to this incident may be of interest to the fire protection profession since the NRTS Fire Department was the first crew to arrive at the scene of the emergency. Other than necessary brief descriptions, this article will be limited to fire department activities during the incident. In a subsequent issue, previous training and future planning as the result of experience gained at the incident will be covered.

The activities of the fire department at this incident may be considered somewhat minor with relation to the extensive emergency operations that took place during the days and weeks immediately following the explosion. However, the fact that a fire department crew comprised the first group of emergency personnel to arrive at the scene of a nuclear reactor accident is a first in fire protection history and, therefore, is significant to the fire protection profession. Fortunately, due to foresight and planning, these personnel were prepared to follow proper procedures and adequately cope with high radiation fields and radioactive contamination, while unassisted by other professional help, during the initial entry into the emergency area. It is hoped that the experience gained by the NRTS Fire Department will be of some benefit to other fire and nonradiological emergency organizations.

The first indication of trouble at the SL-1 Reactor was an automatic alarm, a coded signal punched out on the fire alarm recorders, received at the Atomic Energy Commission fire stations and security headquarters at 9:01 p.m., January 3. The alarm was quickly identified as originating from fixed-temperature fire detection units located inside the SL-1 Reactor Facility. Receipt of this particular alarm did not indicate anything unusual at the time since activation of fire detection units would naturally be associated with fire. In fact, a furnace malfunction had activated the fire detection system at this facility only three weeks before, resulting in routine fire department response. Upon the receipt of the alarm, which in this case could have resulted from either excessive temperature or a pressure surge in the region above the reactor floor, the Central Facilities Fire Department and AEC security forces responded. At this time, a call was placed to request a health physicist (radiation safety specialist) on duty at the Materials Testing Reactor (MTR), located about 11 miles from the SL-1, to report to the scene. This is standard procedure when responding to a facility containing a potential radiological hazard and where a health physicist may not be on duty after normal working hours.

Engines arrive

The fire engines and security forces arrived at the SL-1 site, 8 miles from the central facilities area, at approximately 9:10 p.m. Plant personnel, who normally open the gates and assist in directing the fire department to the scene of the emergency, were not on hand nor could they be contacted by telephone from the gate house. Security patrolmen used pass keys to open the gates in the site area fence and later the south door of the SL-1 administration building. Firemen, equipped with self-contained breathing apparatus and high-range radiation survey meters went through the administration and support facilities buildings in search of the operators and evidence of fire. It is significant to note that these men were also wearing, in addition to regular fire department turnout clothing, self-reading 200 r dosimeters, radiation film badges, rubber gloves, and latex boots. During the initial entry firemen searched all rooms in the administration and support facilities buildings, but found no fire, smoke, nor any personnel. The search progressed to the entrance to the reactor building at which point unusually high levels of radiation were encountered. The firemen then withdrew pending availability of health physics guidance.

Radiation encountered

At 9:17 p.m. the MTR health physicist arrived at the SL-1. Accompanied by a fireman and wearing self-contained breathing apparatus, he proceeded through the administration and support facilities buildings and as far as the foot of the stairs to the operating floor of the reactor building. There they encountered a radiation level of 25 roentgens per hour, the limit of the health physicist’s survey meter. They retreated from the reactor building and thoroughly searched the other buildings looking for the men believed to be on duty. They saw no one, nor any smoke or fire. During this research they encountered radiation fields of from 0.5 to 10 r per hour.

By this time a radio check of other NRTS installations confirmed that the three SL-1 operators had not evacuated to any of them, so it was now presumed they must be in the reactor building. Additional health physicists, on duty at other site facilities, had been called and arrived at 9:35 p.m., already in protective clothing. One of these health physicists, carrying a fire department 500r/hr high-range survey meter, was guided through the facility by a fireman familiar with the layout of the plant. They retreated after encountering a 200r/hr field on the stairs to the reactor building. Then, with AEC approval, a health physicist and an AEC fireman went to the top of the stairs and viewed the reactor floor. Radiation levels of the order of 500r/ hr forced their quick withdrawal. They saw evidence of damage, but no personnel.

Victims found

Meanwhile, stand-by firemen had moved equipment and personnel about one quarter of a mile up the roadway from the facility. By 9:36 p.m., key personnel of the AEC-Idaho Operations Office and Combustion Engineering, Inc. (Operating contractor for SL-1), including the SL-1 plant health physicist and AEC health physics personnel had been notified and were en route to the site. Upon their arrival they were briefed and made the initial entry into the reactor room. They located two men—one moving. The man who was still alive was removed on the next entry, but was pronounced dead by the AEC physician shortly thereafter. During the rescue it was determined that the second man was apparently dead. Another entry was made and the third body was located. The recovery group then retreated to effect personnel decontamination and formulate plans for recoveiy of the remaining two bodies still in the high-radiation area. It should be noted that, although highradiation fields hampered rescue efforts, multiple injuries received at the instant of the explosion were determined to have been the primary cause of death.

To summarize the fire department’s role in emergency activities following the SL-1 accident: They received the initial alarm and were the first crew to arrive at the scene. They made the initial entry, established existence of high-radiation fields, determined no fire had occurred, assisted the first , health physics personnel to arrive at the scene, and provided valuable information for key personnel who subsequently arrived and made the initial recovery. During the first few hours as well as the weeks following the incident, they provided valuable emergency equipment and assisted with decontamination and other emergency work as the need arose. It is felt that their actions during this period reflected good training which provided the ability to cope with emergencies complicated by high-radiation fields. This can be better evaluated by the radiation exposure registered on personnel film badges. Eight of 11 firemen received exposures ranging from .03 to .45 r. The highest exposures were .98 r, 1.06 r, and 1.07 r, respectively. Radiation exposure guides for routine work are 0.3 r per week, 3.0 r per quarter, and as high as 12.0 r per year.

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Exterior view of SL-1 reactor building taken several months before January 3 incident

REACTOR ACCIDENT

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