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By Cari Hachmann

Holtec International, the company that makes canisters for the containment of highly radioactive spent nuclear fuel at San Onofre Nuclear Generating Station (SONGS), recently avoided a $36,250 civil penalty by the U.S. Nuclear Regulatory Commission (NRC).

In an April 29 letter to Holtec, the NRC said it determined the penalty was not warranted because the company took prompt corrective actions and no further aggravated actions took place.

Some of those actions included elimination of the shim pin design, a “lessons learned assessment” to evaluate canister design changes, revised engineering protocols and training shop personnel on issues involving the shims.

Shims are air portals that help keep the radioactive waste cool, while helium gas is pumped in to augment the cooling process.

Southern California Edison officials were surprised last year when a pin in one canister broke off and was heard rattling around inside. Other shim pins were found to be damaged in additional canisters.

As part of an inspection into the matter, the NRC found Holtec responsible for two violations regarding its redesign of four spent nuclear fuel canisters at SONGS.

According to the violation report, Holtec had changed the design of the canisters without NRC approval by inserting steel pins into the bottom, where shims keep the basket for fuel assemblies centered.  The original design did not include the pins, but Holtec added them to improve circulation of helium that cool the canisters.

San Onofre Nuclear Generating Station. File photo: Andrea Swayne
San Onofre Nuclear Generating Station. File photo: Andrea Swayne

NRC gave the New Jersey-based company an opportunity to address the violations identified in its report at a Pre-decisional Enforcement Conference on Jan. 9.

At the meeting, Holtec president and CEO Krishna Singh defended his company’s process, claiming the changes made to the canisters played no role in the safety performance. In a San Clemente Times news article in January, Singh said the shim pin incident was “much ado about nothing.”

While Holtec considered the design changes too insignificant to notify NRC, the federal regulatory commission disagreed.

The commission stated in its letter, “The failure to establish adequate design control measures and obtain NRC approval prior to modifying multi-purpose canisters (MPC) with four-inch stainless steel stand-off pins, was deemed potentially safety significant.”
“Holtec’s design review process for the change did not adequately consider all potential impacts that could adversely affect the safety-related functions of the MPC shims,” the NRC letter continued.

Holtec conducted an analysis to assess consequences of the failure of multiple pins within a canister. According to NRC’s letter, it was determined that the fuel loaded in the canisters wasn’t hot enough to cause problems if pins had broken off.

However, if the fuel was hotter, broken pins “could have compromised the heat characteristics” of the canisters, resulting in increased temperatures beyond the allowable limit and potential damage to the fuel cladding, NRC stated.

Edison released a statement on May 2 in response to the NRC’s final decision on the matter.

John Dobken, media relations manager at SCE, said, “In its letter, the NRC affirmed the canisters utilizing the shim pin design, including the four in use at San Onofre nuclear plant, continue to perform their safety function, and will continue to do so throughout their ‘entire licensed period.’ ”

Dobken said SCE’s pre-loading inspection verified that shims in each of these four canisters were in the as-designed position. All other SCE Holtec MPC-37 canisters utilize a non-shim pin design, he said.

Holtec did not immediately respond to requests for comment from SC Times.

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comments (2)

  • The statement by SCE Dobken that “SCE’s pre-loading inspection verified that shims in each of these four canisters were in the as-designed position” is not true. At the CEP meeting on the shims, SCE Tom Palmisano stated they did not have the tools to inspect the inside bottom of the canisters, so they do not know the condition of the pins in those canisters. Also, Palmisano said lack of the pins may be a problem for transport due to lack of structural support when canisters are transported in the horizontal position, as required. This issue has not been addressed by the NRC.

    Also, there is no actual evidence to support that the cooling system is adequate with or without the pins. The NRC eliminated the requirement to verify that the air cooling system is even working. I asked the NRC if their inspectors plan to verify whether the air cooling system is working. They said the would follow the requirements of the license. This means “no”.

    The NRC, SCE and Holtec have given us evidence they are not protecting our safety. The Governor needs to step in and revoke SCE’s state permits and stop distribution of ratepayer Decommissioning Trust Funds until all thin-wall canisters are replaced with thick-wall transportable storage casks. Until this is done, California is at risk for Chernobyl level disasters. Each canister contains as much radioactivity as the 1986 Chernobyl nuclear disaster.

    The container replacement must be done before this waste can be moved to higher ground on the Mesa or to any other location.

    SCE has left us no other options. See details at

    • Is Donna lying, as usual, confused about the difference between shim standoff pins and the shims themselves, or just smoking crack?

      SCE spokesman, John Dobken’s statement regarding canister shims being verified to be in their “as-designed position” is ABSOLUTELY correct. One doesn’t have to look at the bottom of the “shims” to verify the “shims” are in their correct position axially or vertically. One can determine that the “shim” standoff pins are present by verifying the “shims” are at their proper height. PRIOR to loading the four canisters in question, as well as on every other canister, the “shims” ARE inspected to verify they are in their correct position, just as John Dobken indicated. Donna, whether by design or ignorance, confuses the “shims” with the shim standoff pins attached to the bottom of the “shims”. The dispassionate observer can view the videos of the community engagement panel meetings where the shims are discussed and described in detail. Tom Palmisano had slides picturing the “shims” and shim standoff pins and on the 6/27/18 meeting, he brought in actual models of these shims/standoff pins. These videos confirm that what Donna said is, at a minimum, false. Begin the 3/22/18 CEP meeting at the 1:24: 30-time mark and the 6/27/18 CEP meeting at the 42: 30-time mark.

      The cooling system Donna complains about is fully described in the 6/27/18 CEP meeting video (begin at 39:30) and Tom goes into some depth describing the heat removal capability and the wide margin of safety. Contrary to Donna’s assertion, SCE, Holtec, the NRC, and a third party have verified the calculations regarding these margins. Also, canisters of this type have been in operation for more than 30 years without any problems including problems involving heat removal.

      Claiming we are at risk of a Chernobyl-level accident because of the amount of fuel we store in each canister is a dishonest exercise. Chernobyl was an operating plant with all the attendant energies available to disburse radioactive material, energies that are non-existent here at SONGS.
      Making baseless claims, misquoting and deliberately misrepresenting the experts, the NRC, various engineering studies as well as Holtec and SCE management personnel are repugnant practices that Donna regularly engages in. She militantly refuses to acknowledge that the basis for her rapid corrosion scenario for canister cracking has been thoroughly refuted. Donna has no credibility and her words, novice opinions, and claims for what others have said are untrustworthy at any speed.

      User, beware and forewarned as to her guile.

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