Fire damaging electrical cables in metal trays passing through a concrete wall
On March 22, 1975, a worker used a candle to check for air leaks in the room directly beneath the Unit 1 and Unit 2 control rooms at the Browns Ferry nuclear plant in Alabama.
Electrical cables used to power, control, and monitor equipment throughout the plant passed from panels in the control room through its floor into this room. The cables fanned out from this room, passing through many holes cut through its walls.To protect against radioactivity in the air leaking in through these holes and rising up into the control rooms to threaten the health of the operators, sealing material filled the gaps around the cables where they passed through the walls.
To check for leaks, the worker held the candle as close to the wall penetrations as possible. A steady flame indicated a good seal. A flickering flame meant air was leaking through the penetration.
The worker held the candle too close to one penetration. Its flame ignited flammable material that had been used to seal the gap around cables. The fire quickly spread and burned out of control, blazing for nearly seven hours. Cables damaged by the fire disabled all the emergency core cooling systems for Unit 1 and most of those systems for Unit 2. Only heroic worker actions that day to jury-rig water makeup methods prevented a double reactor meltdown that day.
In 1980, the Nuclear Regulatory Commission (NRC) adopted new fire regulations intended to prevent another Browns Ferry fire—or worse. These common-sense fire protection regulations sought to prevent a single fire from wreaking such widespread damage, and required plants to physically separate electrical cables for a primary safety system from the cables for its backup, or to heavily insulate the cables, so that both sets of safety systems could not be disabled by a single cause.
About two decades later, the NRC’s inspectors discovered that many reactors operating in the U.S. had still not taken these safety measures and failed to comply with its 1980 fire protection regulations. Instead of physically separating or insulating the electrical cables as specified in the regulations, plant owners relied on workers running to the far ends of burned-out cables to manually operate the safety equipment needed to cool the reactor cores. The NRC did not permit such manual actions unless it had formally reviewed and approved them.
In 2004, the NRC revised its fire protection regulations to add a second way to manage the fire hazard at nuclear plants.
These alternative regulations relied on a recently adopted standard (No. 805) by the National Fire Protection Association (NFPA). Called the “NFPA 805” option, these regulations allowed electrical cables to be side-by-side, in fact touching one another, as long as computer modeling of postulated fires showed that fires would be extinguished before the associated heat, smoke, and water damage prevented adequate cooling of the reactor cores.
The owners of 51 reactors formally notified the NRC of their plans to comply with the NFPA 805 fire protection regulations. In doing so, they implicitly conceded that these reactors failed to comply with the 1980 fire protection regulations. After all, no owner could justify spending the millions of dollars needed to comply with the 2004 regulations if it already satisfied the 1980 regulations.
In the eight years since that time only four reactors have taken the steps to comply. Today, 47 of those 51 reactors still do not comply with either the 1980 or 2004 fire regulations.
Ironically and sadly, the three reactors at Browns Ferry are among those that fail to comply with either the 1980 or the 2004 fire protection regulations. That’s right—more than 37 years after a fire nearly melted down the Unit 1 and Unit 2 reactors, these reactors operate in violation of fire protection regulations expressly developed to prevent another Browns Ferry fire.
Bad, but it gets worse.
On May 18, 2012, the NRC granted a request by the Tennessee Valley Authority (TVA), Browns Ferry’s owner, for still more time to comply with the 2004 fire protection regulations.
TVA had promised the NRC in writing on March 4, 2009, that it would transition to the 2004 regulations and submit that plan to the NRC by March 4, 2012.
Liar, liar, plants on fire!
TVA never made it. Instead, TVA wrote to the NRC on January 13, 2012, asking that the deadline for its plan be postponed another year until March 29, 2013.
The NRC is extremely tough about this. They adamantly refuse to grant an extension—unless you ask them for one.
On May 18, 2012, the NRC approved TVA’s extension. The NRC reported:
The NRC staff reviewed the licensee’s compensatory measures, additional modifications, and submittal schedule. Based on the maintenance of acceptable compensatory measures, the planned improvements, proposed modifications, and continued progress toward the submittal of a high quality amendment request, the NRC staff finds that TVA has provided adequate justification for a delay in the submittal date for its NFPA 805 amendment request.
Very reassuring. Too bad the NRC’s statement wasn’t true.
Just 10 days after announcing it had approved the extension, the NRC issued an inspection report documenting the following fire protection violations it had identified during inspections at Browns Ferry between February 6, 2012, and March 1, 2012:
- TVA “failed to adequately identify and perform required training for implementation of four new Safe Shutdown Instructions (SSI)” that would be used to safely shut down the reactor in event of a fire.
- TVA failed “to establish procedures appropriate to the circumstances for combating plant fires. Specifically four new Safe Shutdown Instructions (SSI) were established which contained multiple procedural deficiencies.”
- TVA failed “to assure conditions adverse to quality associated with the establishment and implementation of four new Safe Shutdown Instructions (SSI) were promptly identified and corrected. Specifically, the [NRC] inspectors identified instances were previously identified issued with SSIs were either not entered into the correction action program, corrective actions were not implemented, or the corrective actions were ineffective in addressing the identified issue.”
- TVA failed “to establish adequate compensatory measures for non-conforming fire barriers in accordance with the approved fire protection program (FPP).” Specifically, TVA “failed to establish continuous fire watches for non-conforming fire barriers in the Intake Pumping Station (IPS), after discovering that the barriers were not creditied in the site’s approved FPP.”
Thus, the NRC granted TVA’s request for yet another year to try to achieve compliance with years-old fire protection regulations based largely on compensatory measures and fire protection program elements it had just identified as being inadequate.
We now know that there cannot be another fire accident at Browns Ferry. With TVA and NRC knowing how hazardous fires at this plant can be and how unready Browns Ferry is for a fire, there simply cannot be an accident.
Criminal negligence, maybe. But not an accident.
The United States needs a regulator that aggressively enforces safety regulations, not an agency that facilitates unsafe practices by plant owners.
After all, the NRC itself has said that fire poses a threat essentially equal to all other threats combined, stating:
Approximately one-half of the core damage risk at operating reactors results from accident sequences that initiate with fire events.
Four reactors (Harris in North Carolina, and the three reactors at Oconee in South Carolina) have completed the process to achieve compliance with the 2004 regulations, thus demonstrating undeniably that it can be done in a timely manner. There’s zero excuse for Browns Ferry to operate in violation of fire protection regulations that were initially motivated and adopted because of the Browns Ferry fire.
And it’s totally inexcusable for the NRC to tolerate this pathetic display of nuclear safety nonchalance. They should get their fiddles out and tuned to be ready to play a little tune for the people of northern Alabama while Browns Ferry burns.
“Fission Stories” is a weekly feature by Dave Lochbaum. For more information on nuclear power safety, see the nuclear safety section of UCS’s website and our interactive map, the Nuclear Power Information Tracker.