SDG&E not likely to get reimbursement from ratepayers due to San Onofre shutdown, according to CPUC

SAN ONOFRE - The primary recipients of energy from the now-shuttered San Onofre Nuclear Generating Station -- including San Diego Gas & Electric -- won't be allowed to get reimbursed by ratepayers for purchases of replacement power, according to a proposed California Public Utilities Commission ruling released today, Mon., Sept. 23.

The CPUC's proposed action was unveiled on the same day that the U.S. Nuclear Regulatory Commission announced that the inadequate design of steam generators at SONGS was a safety violation, and that a Notice of Nonconformance was sent to the manufacturer, Mitsubishi Heavy Industries.

An investigation into a small, non-injury leak in one of the two reactors at the nuclear power plant in northern San Diego County in January 2012 found that the cause was vibrations in steam pressure tubes.

The other reactor was undergoing scheduled maintenance at the time -- and both units remained shut down. In June, the plant's operator and majority owner, Southern California Edison, announced the reactors would be retired.

The steam generators were installed in 2010 and 2011.

The decision on who should pay for replacement power still needs final approval by the commission, and is just one of several financial issues related to the decommissioning that regulators need to figure out in the near future.

SDG&E owns 20 percent of the plant and received one-fifth of the power it generated.

"I want to assure customers that they will not pay twice for the costs associated with the outage of San Onofre while the CPUC investigation comes to its conclusion. This is a question of fundamental fairness to customers,'' said CPUC Commissioner Mike Florio. "We expect SCE and SDG&E to continue to procure energy to meet customer needs and according to our long-term plans and renewable energy goals.''

The CPUC ordered SDG&E and Edison to track the replacement power costs separately, pending the completion of the CPUC's investigation. The estimated price tag for SDG&E is $69.4 million -- and it's $271 million for Edison.

The NRC statement said the safety violation was one of low to moderate safety significance.

The agency said its actions against Mitsubishi, which has 30 days to respond, are designed to prevent an occurrence in steam generators installed at U.S. nuclear plants in the future. The design flaw resulted from faulty computer modeling, according to the statement.

Rosemead-based Edison -- which has 10 days to formally respond to the NRC's findings -- contends that computer codes used by the manufacturer in the design of the steam generators inaccurately predicted thermal hydraulic

conditions, leading to tube vibration, wear, and ultimately the leak.

The NRC also found that MHI embedded the same computer modeling error in the design of steam generators at four other nuclear plants, although none developed the fluid elastic instability that caused San Onofre to shut down, according to the utility.

"Mitsubishi designed the system,'' said Pete Dietrich, Edison's senior vice president and chief nuclear officer. "Mitsubishi built the system. Mitsubishi's system failed. They are the experts. SCE was the customer.'

Edison questioned MHI about its computer models during the design process, he said.

Dietrich said it is normal for a plant operator to be cited even though the violation was caused by a vendor or contractor.

A public forum hosted by the NRC on the decommissioning of the reactors at San Onofre is scheduled for Thursday, Sept. 26 at 6 p.m. at the Omni La Costa Resort and Spa in Carlsbad.