2018 - 01- 01 RADIOACTIVE WASTE 101

This document describes high level radioactive waste in general, the way such waste is currently stored at Diablo Canyon, and national policy on long-term storage and "disposal" of radioactive wastes. Pacific Gas and Electric Company (PG&E) is planning to shut down Diablo in the near future, but the radioactive wastes will remain on site for the foreseeable future - decades or possibly centuries to come.


San Luis Obispo Mothers for Peace


Prepared by Spokesperson Jane Swanson, janeslo@icloud.com


FAQs about nuclear waste from commercial reactors:

  • A reactor holds about 100 metric tons of fuel when operating.
  • Fission produces hundreds of harmful radioactive isotopes that do not exist in nature. A few examples:
    • Iodine- 131 concentrates in the thyroid and gets into milk through contaminated grass, causing thyroid cancer. It also concentrates in ovaries causing birth defects and miscarriages.
    • Strontium-90 mimics calcium and concentrates in bone. It can cause Leukemia.
    • Plutonium-239 is highly toxic for 240,000 years. One microscopic speck in the lung will cause lung cancer.
  • For more detailed information see https://www.nirs.org/wp-content/uploads/2017/04/Fact-Sheet_NuclearBasics_HLW_2017Final.pdf

FAQs about radioactive wastes at Diablo Canyon:

  • All the radioactive wastes created since Diablo opened in 1984 are still on site. As of July of 2017 3,280 spent fuel assemblies were stored in spent fuel pools; and 1,568 of those assemblies were in dry casks. So 48% of spent fuel is now in dry casks (See page 3 of http://docketpublic.energy.ca.gov/PublicDocuments/17-IEPR-01/TN220128_20170712T150411_Valerie_Winn_Comments_PGE_Response_to_53117_Nuclear_Data_Request.pdf)
  • According to Dr. Marvin Resnikoff of Radioactive Waste Management Associates, each spent fuel assembly contains the equivalent of 10 Hiroshima bombs measured in long-lived radioactivity.
  • Each of Diablo Canyon Power Plant’s two reactor units is refueled about every 18 months.
  • The “spent fuel” is more than a million times more radioactive than the same fuel before it undergoes fission in a reactor. Spent fuel would kill an unshielded man standing 3 feet away within seconds.
  • When spent fuel is taken out of a Diablo reactor, it is immersed in deep pools of borated water to cool the spent fuel and shield the environment and plant workers from radiation.
  • After 5 to 10 years, the spent fuel is moved underwater into canisters, which are then placed into concrete casks that stand about 20 feet tall.
  • The casks are stored in the open, bolted to a concrete pad. The bolts are designed to keep the casks stable in the event of an earthquake.
  • There is no physical barrier to protect the casks from acts of malice or terrorism, accidental aircraft impact, or other catastrophic events.

National Policy regarding long-term storage of radioactive wastes:

The NRC has allowed spent fuel rods at Diablo Canyon to be stored in spent fuel pools at five times the density of the original design. (See page 4 of http://docketpublic.energy.ca.gov/PublicDocuments/17-IEPR-01/TN220128_20170712T150411_Valerie_Winn_Comments_PGE_Response_to_53117_Nuclear_Data_Request.pdf )

  • Loss of cooling water in a spent fuel pool could lead to a catastrophic spent fuel pool fire.
    • Water could be lost from a spent-fuel pool through leakage, boiling, siphoning, pumping, overturning of the pool, or displacement by objects falling into the pool.
    • If the fuel were exposed to air and steam, the zirconium cladding would react exothermically, catching fire at about 800 degrees Celsius. Radioactive particles would be released into the atmosphere and carried by the wind.
  • The NRC recognizes that dry cask storage is a much safer option than spent fuel storage.
  • The Nuclear Waste Policy Act of 1982 calls for a comprehensive national program for safe and permanent “disposal”/ storage of high- level radioactive waste.
    • Yucca Mountain was at one time designated as a permanent storage site. Under the Obama administration it was abandoned, but currently there is a movement in Congress to go forward with implementing it.
  • Currently the Department of Energy is exploring the concept of Consent-Based Siting of Interim Storage sites. Concerns include
    • the definition of consent;
    • transportation by rail, truck and barge, through major metropolitan areas.


  • In 1973 Mothers for Peace (MFP) received legal standing with the Nuclear Regulatory Commission (then called the Atomic Energy Commission) to oppose PG&E’s application for a license to operate the Diablo Canyon plant, then under construction. MFP’S goal was to permanently block operation of the plant.
    • MFP’s reasons included the nearby Hosgri earthquake fault, lack of a workable emergency plan, and dangers presented by the possibility of terrorism.
    • But the NRC “grandfathered in” the licenses in 1983 and 1985, violating its own regulations that ruled out nuclear facilities located on major, active earthquake faults. The NRC justified its decision because of the billions of dollars PG&E had spent on building the plant.
    • Had MFP been successful, there would be no radioactive wastes on the Central Coast.
  • SLOMFP takes the position that at present the best way to manage the radioactive wastes at Diablo is to put them in Hardened On Site Storage – HOSS.
    • All wastes in dry casks;
    • Behind berms or in concrete bunkers;
    • Retrievable, so that any corroded or leaking casks or canisters could be “repackaged” in fresh casks;
    • Keep an empty spent fuel pool on site, because such re-packing must be done submerged in borated water.



Transportation of Radioactive Wastes

          Kevin Kamps, Radioactive Waste Watchdog, Beyond Nuclear, Washington, DC

Consolidated “Interim” Storage

Diane D’Arrigo, Radioactive Waste Project Director, Nuclear Information Resource Service, Washington, DC