NRC FINALIZES GUIDANCE DOCUMENTS

FOR POST-FUKUSHIMA REQUIREMENTS

The Nuclear Regulatory Commission has issued Interim Staff Guidance (ISG) to U.S. 

nuclear power plants to ensure proper implementation of three Orders the agency issued in 

March, in response to lessons learned from the Fukushima Dai-ichi nuclear accident.

The ISGs represent acceptable approaches to meeting the Orders’ requirements before 

their Dec. 31, 2016, compliance deadline. The ISGs are not mandatory, but U.S. nuclear power 

plants would have to seek NRC approval if they wanted to follow a different compliance 

approach. The NRC issued draft versions of the ISGs on May 31 and asked for public input; the 

final ISGs reflect information gained from the month-long comment period and subsequent 

public meetings.

The first Order requires all U.S. plants to better protect portable safety equipment put in 

place after the 9/11 terrorist attacks and to obtain sufficient equipment to support all reactors and 

spent fuel pools at a given site simultaneously. The ISG for this Order endorses the industry’s 

updated guidance for dealing with a scenario that knocks out all of a plant’s alternating current 

electric sources. The updated approach includes the use of backup power supplies for devices 

that would burn off accident-generated hydrogen before it could accumulate to explosive levels. 

The staff concludes the updted approach will successfully implement the Order. The ISG is 

available in the NRC’s electronic document database, ADAMS, under accession number 

ML12229A174; the associated industry document is available under accession number 

ML12242A378.

The second Order applies only to U.S. boiling-water reactors that have “Mark I” or 

“Mark II” containment designs. Mark I reactors must improve installed venting systems that help 

prevent core damage in the event of an accident; Mark II reactors must install these venting 

systems. The ISG for this Order provides more detailed technical information on the vents, as 

well as how vent designs and operating procedures should avoid, where possible, relying on 

plant personnel taking actions under hazardous conditions. The second ISG is available in 

ADAMS under accession number ML12229A475.

The third Order requires all plants to install enhanced equipment for monitoring water 

levels in each plant’s spent fuel pool. The ISG for this Order largely endorses an industry 

document that the staff concludes will successfully implement the Order. The ISG defines in 

NRC NEWS

U.S. NUCLEAR REGULATORY COMMISSION

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No. 12-097 August 31, 2012
more detail the water levels the new equipment must accurately report, as well as standards for 

equipment mounting, powering and testing, personnel training and other criteria. The final ISG 

notes several areas, including instrument qualifications and instrument protection from falling 

debris, where the industry revised its initial approach. An exception in the staff’s endorsement 

sets specific seismic criteria to ensure the instruments will survive an earthquake. This ISG is 

available in ADAMS under accession number ML12221A339; the associated industry document 

is available under accession number ML12240A304.

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