San Onofre Special Inspection Pre-Decisional Enforcement Conference

On January 24, 2019, the U.S. Nuclear Regulatory Commission (NRC) met with representatives of Southern California Edison Company to discuss preliminary findings of a Special Inspection it conducted at the
 San Onofre Nuclear Generating Station following a fuel-loading incident on August 3, 2018.

The meeting was held from 2:00 – 5:00 p.m. Central Time at the NRC’s Region IV office, which is located at 
1600 E. Lamar Boulevard in Arlington, Texas.  It was open to public observation and was broadcast via webinar.  NRC officials answered questions submitted via the Internet from the public following the business portion of the meeting.

No decision on the final safety significance of the findings identified in a November 2019 inspection report or any additional NRC actions were made at the conference.  That decision will be announced at a later date.

Overview of Issues and Inspection

On September 10-14, 2018, NRC officials conducted a Special Inspection at the San Onofre facility in San Clemente, California.  The inspection was conducted in response to the misalignment of a loaded spent fuel storage canister as it was being downloaded into the storage vault at the San Onofre Nuclear Generating Station (SONGS).

Based on the results of the Special Inspection, two apparent violations were identified and are being considered for escalated enforcement action in accordance with the NRC Enforcement Policy.  The apparent violations involved the failure to:

  • ensure important-to-safety equipment was available to provide redundant drop protection features for a spent fuel canister during downloading operations; and,
  • make a timely notification to the NRC Headquarters Operations Center for the disabling of important-to-safety equipment on August 3, 2018.

The circumstances surrounding these apparent violations, the significance of the associated issues, and the need for corrective actions were discussed with San Onofre officials at the conclusion of the onsite inspection and during the final telephonic exit briefing.

Inspection Report

In a December 2018 letter transmitting the inspection findings to San Onofre officials, NRC stated as follows:

The NRC is concerned about apparent weaknesses in management oversight of the dry cask storage operations.  Your staff did not perform adequate direct observational oversight of downloading activities performed by your contractor, ensure adequate training of individuals responsible for performing downloading operations, provide adequate procedures for downloading operations, or ensure that conditions adverse to quality were entered into the corrective action program.  The NRC identified that a causal factor for the misalignment incident involved management weakness in the oversight of dry cask storage operations.

According to NRC’s letter, agency officials determined that three Severity Level IV violations of NRC requirements occurred.  The violations involved failures to:

  • identify conditions potentially adverse to quality for placement into San Onofre’s corrective actions program;
  • assure that operations of importance to safety equipment were limited to trained and certified personnel or under direct supervision; and,
  • provide adequate procedures for dry cask storage operations involving downloading operations.

The NRC determined the issuance of a Notice of Violation is appropriate because the actions to restore compliance have not been fully developed and implemented and the actions must be effective prior to beginning fuel-handling activities.


Southern California Edison owns the San Onofre Nuclear Generating Station.  The plant is located in San Clemente, California.  It permanently shut down in 2013.

A copy of the November 2018 San Onofre Nuclear Generating Station inspection report is available online at  

For additional information, please contact Victor Dricks at (817) 200-1128.

Enforcement Action Initiated Against Holtec re Spent Fuel Cask Design

On December 27, 2018, the U.S. Nuclear Regulatory Commission (NRC) announced that the agency plans to bring an enforcement action against Holtec International — the manufacturer of the steel and concrete casks used at the Vermont Yankee nuclear power plant to store spent fuel.

NRC officials held a pre-decisional enforcement conference with Holtec officials from 1:00 – 5:00 p.m. ET on January 9, 2019.  The conference, which was held in the Commission Hearing Room at NRC Headquarters, was open to the public and webcast.

For additional information on the webcast, please go to


The issue originated when a loose bolt was identified in the 18-foot tall casks at the San Onofre Nuclear Generating Station in California in March 2018.  Workers at the San Onofre Nuclear power plant discovered a loose four-inch stainless steel pin at the bottom of a canister as it was being prepared for loading with spent fuel.  The pin was part of a shim designed to support the fuel basket and allow airflow to the fuel assemblies within the canister.  As such, the shim is considered essential to the function of the fuel basket.  Regulators are concerned that the problem could affect the ability of the casks to effectively cool the nuclear fuel.

Since the Vermont Yankee plant shares a similar cask design as San Onofre, a two-month halt was initiated earlier this year when Entergy Nuclear Corporation was transferring the plant’s spent nuclear fuel to the air-cooled storage casks.  The transfer resumed in May 2018 and was completed this past summer.

During the two-month hiatus at Vermont Yankee, Entergy inspected the empty Holtec Hi-Storm 100 casks that Holtec had already provided for the fuel transfer and storage project and found no problems with the casks.  Entergy used a total of 58 casks, but it could not inspect the canisters already filled with fuel.  According to NRC, 31 of the 58 casks at the Vernon site were of the new Holtec design.

Transfer of the spent fuel was a key condition of the pending sale of Vermont Yankee by Entergy to NorthStar Holding Company.  The sale, which has received both state and federal approval, is expected to be completed early in the 2019 calendar year.


The action against Holtec International involves a new design that the company adopted for its casks before getting NRC approval.  The design has since been approved, according to an agency representative.

In particular, NRC asserts that Holtec changed the design of the Hi-Storm 100 casks — specifically the four-inch stainless steel pins that hold the basket, which in turn holds the spent fuel.  Holtec determined that it did not need to conduct a written evaluation, which was a violation of NRC safety regulations according to agency officials.  In the notice of violation from the NRC, the agency referred to “nonconforming and degraded conditions at both SONGS (San Onofre Generating Station) and VY [Vermont Yankee], respectively.”

NRC conducted an inspection at Holtec’s offices in Camden, New Jersey.  On November 29, 2018, NRC issued an inspection report identifying two apparent violations of the agency’s quality assurance regulations.  The NRC determined Holtec, when it changed the shim to the pin design in 2016, failed to establish adequate design control measures for selecting and applying materials, parts, equipment and processes essential to the function of safety-related structures, systems and components.  Holtec also failed to maintain written records of changes to its canister design, including an evaluation of why the design change could be implemented without applying to the NRC for an amendment to the canister’s Certificate of Compliance.

The NRC offered Holtec a choice between the pre-decisional enforcement conference or third-party mediation.  Holtec chose the conference, during which its officials will be able to present additional information for the NRC staff to consider in assessing the significance of the subject violations.  No final action will be taken at the conference on January 9, 2019.In addition to San Onofre and Vermont Yankee, the Holtec Hi-Storm 100 casks were also used to store spent fuel at nuclear plants including Dresden in Illinois; Grand Gulf in Mississippi; Hatch in Georgia; Columbia in Washington; Watts Bar in Tennessee; and, Callaway in Missouri.

For additional information, please contact David McIntyre of the NRC at (301) 415-8200.

San Onofre Nuclear Plant Decommissioning Contract Awarded

In late-December 2016, following a ten-month competitive bid process, Southern California Edison announced that it has selected a joint venture of AECOM and EnergySolutions as the Decommissioning General Contractor for the San Onofre Nuclear Generating Station (SONGS).  This is one of the country’s largest commercial nuclear plant decommissioning projects.  The joint venture will be known as SONGS Decommissioning Solutions.


The major SONGS dismantlement work will not begin before 2018 when, as required by the California Environmental Quality Act, state regulators are expected to complete their environmental review.  The project is expected to create about 600 jobs during the 10-year dismantlement phase, including workers from local companies.

AECOM, a fully integrated global infrastructure firm, was named one of Fortune magazine’s “World’s Most Admired Companies” in 2016.  AECOM designs, builds, finances and operates assets in more than 150 countries.  EnergySolutions, which specializes in nuclear plant decommissioning and waste management, is currently in the demolition phase of decommissioning both the Zion and Dairyland nuclear power stations.

The $4.4 billion nuclear plant decommissioning is financed through existing trust funds, including SCE’s share of the project as majority owner.  The total cost includes the dismantlement work awarded to SONGS Decommissioning Solutions and continued on-site storage of San Onofre’s used nuclear fuel until the federal government provides a required repository and restoration activities.

SCE shares responsibility for decommissioning with San Onofre co-owners San Diego Gas & Electric and the city of Riverside, as well as former co-owner the city of Anaheim.


When operational, San Onofre Units 2 and 3 generated 2,200 megawatts of electricity.  In June 2013, SCE announced that it would retire San Onofre Units 2 and 3 and that it had begun the preparations to decommission the facility.  SCE has established core principles of safety, stewardship and engagement to guide decommissioning.

An Edison International company, Southern California Edison is one of the nation’s largest electric utilities, serving a population of nearly 15 million via 5 million customer accounts in a 50,000-square-mile service area within Central, Coastal and Southern California.

For additional information, please visit or contact Liese Mosher, Principal Manager, Decommissioning Communications, at Southern California Edison, at (949) 368-9750 or at; Kathy Davis, Executive Director, Southwestern Low-Level Radioactive Waste Compact Commission at (916) 448-2390 or at; or, Stephen Woods, Chief, Division of Food, Drug and Safety, California Department of Public Health, at (916) 440-7883 or at