to Portfolio

Summer 1996
The Nuclear Professional

© 1996
National Academy for Nuclear Training

All rights reserved.

See also:

Cause linked to guide structure damage

Repairs carried out under intense media scrutiny
As the recovery teams began work, a reporter for a Phoenix newspaper, The Arizona Republic, read about the stuck fuel assembly on the Nuclear Regulatory Commission’s home page on the Internet. The resulting article on the front page of the March 31 issue began, "Highly radioactive fuel rods are stuck in one of the reactors at the Palo Verde Nuclear Generating Station, leaving officials worried about how to remove them without risking a release of deadly radioactive gas."

The media interest became so intense that Palo Verde communications personnel established a media center in the plant’s Energy Information Center. Over the next eight days, there were more than 500 interviews and articles on the status of the assembly, including a live remote from a talk radio station.

In response, Palo Verde scheduled daily press conferences at 11 a.m. Executive Vice President Bill Stewart and vice presidents Jack Bailey, Gregg Overbeck and Jim Levine served as spokesmen, explaining what was being done to deal with the problem.

The daily presence of media led to some memorable moments – the most memorable being Thursday, April 4. At this point, the plan for removing the bundle had been approved, and reporters were informed that preparations were under way. Two television stations were at the plant doing live reports when, unrelated to the fuel bundle issue, fire broke out in an electrical panel near the Unit 2 control room. Sirens blared, the PA system announced that an alert had been declared – and, since it was about 5 p.m., the day shift was leaving. Most Palo Verde employees live a long way from the plant, and many commute in vans. The reporters, seeing 75 white vans leaving the site, reported that an evacuation was in progress. In fact, the fire was put out in a few minutes, and the alert ended 50 minutes after it began.

Says Bailey, "One of the lessons we learned is that you need to recognize occurrences that have the potential to create a lot of public concern. The reporters kept asking, ‘Why didn’t you tell us there was a stuck fuel bundle?’ We were treating this like any other fuel transfer problem, and it never occurred to us. But this was unique and deals with the very heart of nuclear power, the reactor core. It doesn’t mean we were hiding anything. We reacted well, but it would have been better to be ahead of the game."

On April 2, the reporters were invited into containment to see the fuel bundle. Recalls Bailey, "Our first reaction was, ‘Nobody can go into containment.’ But it turned out to be extremely effective. When one reporter saw that lone fuel bundle, he said, ‘That’s it?’" The security badging, radiation protection measures and general professionalism impressed the reporters and resulted in generally more balanced stories.

Stewart says, "I think this type of publicity comes with the territory – and we in the nuclear industry have an obligation to educate the public. In the long run, I think it served us well. It gave the public an idea of the conservatism and professionalism of our people."

Cause linked to guide structure damage
The damage to the Alpha 7 fuel assembly apparently occurred during the previous refueling. A guide tube in the massive upper guide structure was damaged, probably when the structure was being placed in its temporary stand in the fuel pool.

When the guide structure was lowered onto the core, the damaged alignment tube slipped over the metal top of the fuel assembly guide post but did not slide over the straight portion. The 100,000-pound weight of the upper guide structure was transferred to the guide tubes. The pressure ruptured the lower end plate and pushed the legs on the bottom of the assembly outward, wedging the assembly against the guide pins that ensure the assemblies are correctly placed.

The cause was both design weakness and human error, says Engineering Vice President Jack Bailey. The temporary stand has no guides to ensure the upper guide structure is put down correctly, says Bailey. "The problem is, we had not recognized it as a design weakness."

It had always been difficult to get the upper guide structure into the stand correctly, but no one realized that the massive tubes could be damaged significantly. "We learned to live with the difficulty in moving the guide structure, believing that all that steel was unaffected by bumps or misplacements in the stand," says Bailey. "Our fix is probably going to be guide pins that force the assembly into the correct placement."

Executive Vice President Bill Stewart adds, "The fact that we handled it well doesn’t undo the fact that this shouldn’t have happened. We can work to keep this from happening again, but it gave us cause to ponder the processes we use."

To "The Freeing of Alpha 7"