The Energy Net

International Reactors
Soviet Reactors Database
    NEA: Chernobyl Report
U.S. Reactors
   U.S. Nuclear Power Reactors
   NRC'S History of Regulation
   Scheduled Reactor Outages
   CRACII: Reactor Accident Study
   Terrorism at Nuclear facilities
California Reactors
    40 Years of California Activism
    Nuclear Energy in California
   The California Ballot Issue
Rancho Seco
   Rancho Seco Timeline
Diablo Canyon
    Diablo Canyon Timeline Part I:
    Diablo Canyon Timeline Part II:
    Diablo Canyon Settlement
    PG&E financial Statements
    Coast & Ocean Autumn 1999-1
    Environmental Working Group
    Myth:Diablo Blockade
    Rate Case and Litigation Support
    Severe Accident Cost Estimates
    Bonnie Raitt: Benefit Appearances Diablo Canyon
    DOE: Annual Reports
    WLA:Engineering Projects
    Ionic Chemical Supply Products
    CERES:Energy development
    Enercon Services, Inc. Links
    Index PIX
    Yahoo: Atomic justice Message
    NE 267
    D.97-08-056 D.97-08-056
    The Anti-Nuclear Movement
    PG&E Environmental Report
    ROADWHORE: Nuclear

We Almost Lost Shasta Watershed

Rancho Seco Near-Disaster Covered Up by Utility

On December 26th, 1985 at 4:17 A.M., the Rancho Seco reactor located southeast of Sacramento came extremely close to a meltdown. The reactor with a hundred accidents under its belt (twice the average for reactors its age) and three of the most serious cooldowns in the industry has created a political and economic crisis for the Sacramento Municipal Utility Commission (SMUD) that may lead to the permanent shutdown of the reactor or even bankruptcy of the utility. It has been shutdown since the accident, and only has a 40% chance of coming back on line by June 1987. The accident did not come to the public's attention until after the Chernobyl disaster. What's most chilling however, is the fact that the public never learned just how serious the accident was.

In piecing together the events from the NRC's own investigation, it becomes clear that the event was far more serious than a mere mechanical foul-up, as claimed by SMUD. The accident, caused by a loose wire, cut off power to the Integrated Control System (ICS) for 26 minutes. The ICS is the computer system that regulates the temperature of the reactor and the steam system to the turbine generator. In other words, the operators lost control of the reactor from the control room.

Workers were dispatched to various parts of the facility in attempts to head off a loss of coolant accident (LOCA). LOCA's are the dreaded scenario almost sure to lead to a meltdown. Two of the workers were contaminated in their attempt to reach critical valves.

Operators were successfull at stopping the LOCA but did not have accurate preocedures for maintaining control of the reactor from outside the control room. As a result, the reactor vessel cooled down to quickly. When this occurs, the 8 inch thick walls of the reactor may shatter, crack or become embrittled reducing the usable lifetime for the unit. During the accident the following serious events ocurred:

  • At 4:52 AM, at the height of the crisis, a back-up shift operator collapsed and had tobe taken to the hospital. The shift was at a bare minimum level before his collapse.
  • Attempts to call for help were useless because the switch-board operator on duty did not have the phone numbers of the next shift.
  • No alarm was sounded within the facility, so the Rad/Chem team did not do monitoring for contamination during the most crucial stages of the accident. Contanubated areas were not cordoned off, resulting in the dosing of an unaware security guard.
  • Required updates of the accident to state emergency officials weren't done, nor were they given correct details of the accident to allow proper emergency response preparations.
  • The alarm system in the control room was so loud that operators could not hear themselves talk, increasing the tension during the crisis. The alarms were shut off but not properly reset to warn of further problems.
  • There was radioactive contamination of the Auxiliary Building and releases of radiation offsite. The utility estimated that 33 curies of noble gases were released to the environment. The 30 curies of Xenon that were released, rapidly turn into radioactive Iodine. The NRC and SMUD claimed this amount would not do damage to the environment.
  • The stack radiation monitors at the complex that were set at 60,000 counts per minute (CPM) were tripped at 5:05 AM, setting off state emergency alarms in Sacramento (the 60,000 CPM level is 7,500 times higher than normal background radiation). The monitor levels were supposed to be set at 20,000 CPM rather than at 60,000 CPM. Another of the monitors had run out of ink, making it impossible to get accurate release readings. The true level of offsite radiation releases is clearly in question.
  • Damage included destruction of a large make-up pump that burned at the start of the incident. Core Assemblies in the reactor were also lifted from their normal positions. The investigations showed that there was no seriouis damage to the reactor core.
  • During the remote manipulation of the valves, one valve was stuck in the open position and unable to be closed. Another valve was turned off by one operator, but broken back into the open position when another operator by, thinking the valve still open. Operators were later given training in proper operation of valves. Another pump that was part of the reason for the rapid cooldown was completely forgotten to be turned off.
  • No log was kept during the accident because the operators were too busy trying to deal with the accident. Operator coments registered with the NRC called SMUD training "terrible" and complained of complacent management. Quizzing of operators showed extensive weaknesses in a variety of procedures for running the reactor.

    The details of the accident left the NRC strongly concerned about whether or not such a small utility as SMUD couldsafely opoerate a reactor. Their statement that the reactor was equivalent to a car being driven for 150,000 miles without a tune-up is a strong analogy for a very dangerous threat to Californians. The NRV went on to fine SMUD over $600,000 in penalties due to violations of NRC procedures and regulations. An outcome of the evaluation of the accident included the discovery that SMUD ignored sumptoms from the ICS in a similar incident on Decmeber 5, 1985. The NRC listed 38 issues, of which 18 had been closed by May 1986, that had to be cleared before the reactor would be allowed to be restarted.

    The accident was not an isolated occurrance. Rancho Seco has had a steadily increasing number of mishaps and violations that started when the reactor was first opened in 1975. Some of the highlights of Rancho Seco:

  • Three of the worst overcooling incidents in U.S. history, with the 1st, 3rd and 9th worst accidents on record.
  • Two workers were killed from a June 1984 steam pipe rupture similar to the one that killed 4 people at the Surry reactor in Virginia in 1986.
  • 13 million gallons of radioactive effluent were dumped into the nearby Clay Creek due primarily to waste storage capacity problems.
  • A class action suit was filed against the utility by 142 residents living near the reactor for damages to health, property and livestock (the suit is still underway).
  • Changes mandated by the NRC in the wake of the Three Mile Island Accident have not all been completed.
  • Outright lying to the NRC may have ocurred. In the latest case the NRC is investigating possible falsification of improperly laid back-up safety wiring. The utility may be forced to rewire much of the 250,000 miles of wire at the reactor if the back-up safety system wiring was not routed differently from the primary safety wiring.
  • Rancho Seco has one of the worst operating levels in the U.S. It has operated only 42% of the time during its first 11 years. It has not operated at all during its twelfth year. The NRC has classified the reactor as one of the worst 5 in the country.
  • Maintenance personnel were poorly trained and as a result, poor maintenance practices throughout the facility have been ocurring for years. One worker was found unable to correctly read gauges. One of the valves involved in the December accident was also found to have not been given any preventive maintenance care for 11 years.
  • In 1980, the Polar Crane cable snapped as it was holding a 3,000 Pound metal plate, just barely missing the reactor. The plate was lifted 10 feet off the gound when regulations only allowed for 6 inches. The crane had been lifting a 7 ton weight over the spent fuel pond prior to the above incident.
  • Problems at Rancho Seco date from the initial decision to build a Babcock and Wilcox reactor, a twin to the reactor at Three Mile Island, which suffered the worst accident to date in the U.S. B&W reactors are known to be the most delicately built reactors in the country and are susceptable to severe problems if not properly maintained.

    After the Chernobyl accident, an in depth look at the reactor by the local media created a strong concern in the Sacramento area for the shutdown of the reactor. In an October 1986 poll, 55% of the residents did not want the reactor to be reopened. Sacramentans for Safe Energy has mounted an initiative drive that would permanently shut down Rancho Seco. They are well on their way to collecting the 40,000 signatures needed to hold a special election before SMUD will be able to get the reactor ack on line. The utility has used the claim that it would cost ratepayers an additional 84% increase in rates besides the cost of decommissioning, if Rancho Seco never reopens. Ratepayers will have already been hit up with a 50% rate increase during the down time of the reactor.

    Failure of the initiative will lead to the likely reopening of the reactor by the NRC (who has pulled only two other reactor liecenses in its recent history-- The Vallacitos reactor Hayward and the Humboldt reactor near Arcata, Ca.){since then Peachbottom I had its license removed in late 87}. If the reactor does reopen it will jeopardize the lives of more than eight million people around central California. A primary water source for the entire East Bay is less than 15 milles downwind of the reactor. This area is also one of the largest agricultural regions in the United States. Dr. John Gofman, the noted health-physicist has suggested that Northern Californians migrate if Rancho Seco is allowed to be put back on line. The Abalone Alliance Clearhouse agrees.

    Sources: Sacramento Bee, San Jose Mercury News & Nuclear Regulatory Commission accident report Produced by the Abalone Alliance Clearinghouse office Spring 1986

    On June 6th, 1989 Sacramento Citizens went to the polls and voted to permanently closed Rancho Seco.