Operations at the Oyster Creek Nuclear Power Plant in Lacey might have become hectic during Hurricane Sandy, but were never touch-and-go, says the Nuclear Regulatory Commission in response to U.S. Senator Robert Menendez (D-NJ).

In terse but detailed terms, the agency today issued its point-by-point response to the Senator's inquiry. Menendez attributed his interest to concerns raised by residents.

NRC admitted that all but three of the Lacey generating station's 42 emergency sirens failed amid storm damage and power outages, but noted that only New York's Indian Point plant meets the criteria dictating backup power for its warning system. The Energy Policy Act stipulates it for nuclear plants with more than 15,000,000 people in a 50-mile radius.

Exelon, says the agency, is voluntarily installing new sirens with battery backup capabilities by June 1 of this year. The federal statute requires only a backup system, which until now has consisted of "route alerting," emergency personnel using mobile public address systems.

Regarding the capability of diesel generators during extended offsite power outages, NRC noted that Exelon entered the storm with filled fuel tanks for each of its two engines, capable of running for seven days before needing refueling. The loss of electricity to the plant itself was an outgrowth of the storm.

NRC offered assurances that flood water reached no "safety-related electrical infrastructure," and that service water motor enclosures remained above flood levels. Visual inspection of the intake structure, the report says, "identified a piece of non-safety electrical equipment that exhibited some degradation" and was replaced. It does not specify the gear.

Menendez relayed concerns about possible compromises of the dry-cask storage zone for spent fuel rods. The NRC responded that the storage site is 23 feet above sea level, about a foot higher than the highest expected storm flood level. Flood levels registered 7.4 feet at the plant, according to the agency. The system, says the report, can handle flood water to a depth of 50 feet and flowing up to 15 feet per second.

Exelon is under NRC instruction to complete flood hazard re-evaluations as part of an ongoing procedure in the aftermath of Japan's Fukushima Daichi tsunami-related disaster. The study is due by March 2015.

Agency officials did not fulfill the Senator's request for release of Exelon analysis data regarding two repair issues raised by critics of plant operations, and indicated that they wouldn't ask the company to comply.

One involves a weld on a reactor vessel control rod injection nozzle, and the other a "pinhole leak" on a reactor head penetration flange discovered during offline repairs. Officials did include a copy of their own publicly-issued inspection report, adding that their on-site inspectors verified repairs in each instance.