ML092510055 

UNITED STATES 

NUCLEAR REGULATORY COMMISSION 

OFFICE OF NUCLEAR REACTOR REGULATION 

OFFICE OF NUCLEAR MATERIAL SAFETY AND SAFEGUARDS 

OFFICE OF FEDERAL AND STATE MATERIALS AND 

ENVIRONMENTAL MANAGEMENT PROGRAMS 

OFFICE OF NEW REACTORS 

WASHINGTON, DC 20555-0001 

November 13, 2009 

NRC INFORMATION NOTICE 2009-27: REVISED INTERNATIONAL NUCLEAR AND 

 RADIOLOGICAL EVENT SCALE USER’S MANUAL 

ADDRESSEES 

All holders of a license, certificate, permit, approval, or registration issued under Title 10 of the 

Code of Federal Regulations (10 CFR). Specifically, this includes: 

All holders of an operating license or construction permit for a power reactor, test reactor or 

research reactor issued under 10 CFR Part 50. 

All holders of or applicants for an early site permit, standard design certification, standard 

design approval, manufacturing license, or combined license issued under 10 CFR Part 52. 

All holders of a materials license, certificate, approval, or registration issued under 

10 CFR Parts 30, 31 through 36, 39, 40, 61, 70, 71, 72, and 76. 

All Agreement State Radiation Control Program Directors and State Liaison Officers. 

PURPOSE 

The U.S. Nuclear Regulatory Commission (NRC) is issuing this information notice (IN) to inform 

addressees that the 63 Member States of the International Atomic Energy Agency (IAEA) have 

approved an updated version of the International Nuclear and Radiological Event Scale (INES) 

User’s Manual. The NRC will use this updated guidance to submit information to the IAEA on 

certain reactor, fuel cycle facility, and materials events. This IN does not contain NRC 

requirements. It is for information purposes only, and no specific action or written response is 

required. 

BACKGROUND 

In 1990, international experts convened by the IAEA and the Organization for Economic 

Cooperation and Development, Nuclear Energy Agency developed the INES with the aim of 

communicating the safety significance of events at nuclear facilities. As described in NRC 

Generic Letter 1992-09, “Limited Participation by NRC in the IAEA International Nuclear Event 

Scale,” dated December 31, 1992 (Agencywide Documents Access and Management System 

(ADAMS) Accession No. ML031070459), the NRC initiated limited use of the system in 1992 to 
IN 2009-27 

Page 2 of 3 

rate reactor events that resulted in the declaration of an “Alert” or higher emergency 

classification. After further review, and as described in NRC Regulatory Issue 

Summary 2002-01, “Changes to NRC Participation in the International Nuclear Event Scale,” 

dated January 14, 2002 (ADAMS Accession No. ML013200502), the NRC expanded its 

participation to include events associated with various other sources of radiation. NRC 

participation now covers a wide spectrum of practices, including industrial uses such as 

radiography, radiation sources in hospitals, activities at nuclear facilities, and the transport of 

radioactive material. By putting events from all these practices into a proper perspective, use of 

INES can facilitate a common understanding between the technical community, the media, and 

the public. 

DISCUSSION 

Events are classified on the INES scale at seven levels: Levels 4-7 are termed “accidents” and 

Levels 1-3 “incidents.” Events without safety significance are classified as “Below Scale/Level 

0.” An explanation of the classification levels can be found at http://www.iaea.org/Publications

/Factsheets/English/ines.pdf. The NRC transmits information to the INES website only for those 

events rated at a Level 2 or higher unless an event rating is specifically requested by another 

IAEA Member State. Since beginning full participation in 2002, this threshold has resulted in 

less than one reactor event per year submitted to IAEA, and on average about 5 materials 

events per year. 

In June 2008, 63 Member States of the IAEA approved a revised edition of the INES User’s 

Manual (2008 Edition), to aid in the rating of events, which has just been published by the IAEA 

(see http://www-pub.iaea.org/MTCD/publications/PubDetails.asp?pubId=8120). The updated 

manual includes the information from the 2001 INES User’s Manual, which focused primarily on 

reactors and fuel cycle facilities, and incorporates further guidance for the rating of materials 

events, including those involving the transport, storage, and use of radioactive material and 

radiation sources. The INES User’s Manual (2008 Edition) is now being used by the NRC and 

the Agreement States to assist in determining the rating of events and to transmit those that are 

INES Level 2 or higher. The NRC will continue its current practice of notifying the IAEA within 

2 business days when an event at a U.S. facility has a provisional INES rating of Level 2 or 

higher. Notifications are immediately posted for public viewing at the IAEA Web site http://wwwnews.iaea.org/news/. The changes incorporated into the INES User’s Manual (2008 Edition) 

should be transparent to licensees. 
IN 2009-27 

Page 3 of 3 

CONTACT 

This information notice requires no specific action or written response. Please direct any 

questions about this matter to the technical contacts listed below. 

/RA by TQuay for/ /RA/ 

Timothy J. McGinty, Director Daniel H. Dorman, Director 

Division of Policy and Rulemaking Division of Fuel Cycle Safety and Safeguards 

Office of Nuclear Reactor Regulation Office of Nuclear Material Safety and Safeguards 

/RA/ /RA/ 

Robert Lewis, Director Glenn Tracy, Director 

Division of Materials Safety Division of Construction Inspection 

 and State Agreements and Operational Programs 

Office of Federal and State Materials and Office of New Reactors 

 Environmental Management Programs 

Technical Contacts: Rebecca Sigmon, NRR Cynthia G. Jones, Ph.D., NSIR 

(301) 415-4018 (301) 415-0298 

E-mail: rebecca.sigmon@nrc.gov E-mail: cynthia.jones@nrc.gov

Note: NRC generic communications may be found on the NRC public Web site, 

http://www.nrc.gov, under Electronic Reading Room/Document Collections. 
IN 2009-27 

Page 3 of 3 

CONTACT 

This information notice requires no specific action or written response. Please direct any 

questions about this matter to the technical contacts listed below. 

/RA by TQuay for/ /RA/ 

Timothy J. McGinty, Director Daniel H. Dorman, Director 

Division of Policy and Rulemaking Division of Fuel Cycle Safety and Safeguards 

Office of Nuclear Reactor Regulation Office of Nuclear Material Safety and Safeguards 

/RA/ /RA/ 

Robert Lewis, Director Glenn Tracy, Director 

Division of Materials Safety Division of Construction Inspection 

 and State Agreements and Operational Programs 

Office of Federal and State Materials and Office of New Reactors 

 Environmental Management Programs 

Technical Contacts: Rebecca Sigmon, NRR Cynthia G. Jones, Ph.D., NSIR 

(301) 415-4018 (301) 415-0298 

E-mail: rebecca.sigmon@nrc.gov E-mail: cynthia.jones@nrc.gov

Note: NRC generic communications may be found on the NRC public Web site, 

http://www.nrc.gov, under Electronic Reading Room/Document Collections. 

ADAMS Accession Number: ML092510055 TAC ME1764 

OFFICE DIRS/IOEB Tech Editor BC/DIRS/IOEB D/NRR/DIRS 

NAME RSigmon CHsu EThomas for JThorp McC for FBrown 

DATE 9/9/09 9/11/09 email 10/2/09 10/5/09 

OFFICE NSIR PGCB:DPR PGCB:DPR BC:PGCB:DPR 

NAME CJones DBeaulieu CHawes MMurphy 

DATE 10/6/09 10/6/09 10/28/09 11/13/09 

OFFICE NRO FSME NMSS D:DPR 

NAME GTracy RLewis DDorman TMcGinty (TQuay for) 

DATE 11/03/09 11/06/09 11/10/09 11/13/09 

OFFICIAL RECORD COPY