ML15215A502 

UNITED STATES 

NUCLEAR REGULATORY COMMISSION 

OFFICE OF NUCLEAR REACTOR REGULATION 

OFFICE OF NEW REACTORS 

WASHINGTON, DC 20555-0001 

November 20, 2015 

NRC INFORMATION NOTICE 2015-12: UNACCOUNTED FOR ERROR TERMS 

ASSOCIATED WITH THE IRRADIATION TESTING 

AND ENVIRONMENTAL QUALIFICATION OF 

IMPORTANT-TO-SAFETY COMPONENTS 

ADDRESSEES

All holders of an operating license or construction permit for a nuclear power reactor issued 

under Title 10 of the Code of Federal Regulations (10 CFR) Part 50, “Domestic Licensing of 

Production and Utilization Facilities,” except those that have permanently ceased operations 

and have certified that fuel has been permanently removed from the reactor vessel. 

All holders of and applicants for a power reactor early site permit, combined license, standard 

design approval, or manufacturing license under 10 CFR Part 52, “Licenses, Certifications, and 

Approvals for Nuclear Power Plants.” All applicants for a standard design certification, including 

such applicants after initial issuance of a design certification rule. 

PURPOSE

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

addressees of issues identified by the NRC staff concerning unaccounted for error terms 

associated with the irradiation testing and environmental qualification of important-to-safety 

components. The NRC expects that recipients will review the information for applicability to 

their facilities and consider actions, as appropriate, to address the identified issues and avoid 

similar problems. No specific action or written response is required. 

DESCRIPTION OF CIRCUMSTANCES

The environmental qualification of nuclear components is performed by specialized test facilities 

that have the equipment necessary to simulate the conditions (i.e., temperature, pressure, 

humidity, chemical spray, etc.) that would be expected during a nuclear accident. While such 

facilities often have specialized environmental chambers for simulating nuclear accident 

environments, they rarely have the capability to perform the irradiation of nuclear components 

as required by the qualification process. The irradiation phase of the qualification process is 

typically performed before subjecting a component to the accident environment. As such, the 

large majority of nuclear component irradiations performed as part of nuclear equipment 

qualification programs is, and were, subcontracted out to a few specialized facilities. Steris 

Isomedix in Whippany, New Jersey, is one such facility where a large number of nuclear 

components were irradiated as part of an environmental qualification process. 
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During an NRC vendor inspection conducted in April 2014, at Steris, (Agencywide Documents 

Access and Management System (ADAMS) Accession No. ML14128A117), the NRC identified 

that Steris had failed to ensure that the measuring and testing system (e.g., the dosimeters, 

associated procedures, and dosimetry reading equipment) used to determine the applied 

radiation dose to the nuclear components being tested was properly controlled. Specifically, 

Steris had not accounted for all variability in the irradiation process. The NRC identified that 

Steris had failed to account for the density of other products placed into the irradiation chamber, 

source decay, and location within the irradiation chamber. As a consequence, inspectors 

identified the actual radiation dose applied to nuclear components as potentially being less than 

what was reported on the irradiation certificates of conformance provided by Steris. 

Subsequent to the NRC inspection, on June 18, 2014, Steris notified its customers under the 

requirements of 10 CFR Part 21, “Reporting of Defects and Noncompliance,” that the actual 

radiation dose applied to components irradiated at the Steris Whippany facility might not have 

been achieved as certified by Steris. At the time the Part 21 notification was issued, the 

unaccounted for variability in the irradiation process was thought by Steris to be as much as 

5.1 percent. This was in addition to a 6.5 percent measurement uncertainty associated with the 

Harwell Red 4034 Perspex dosimetry utilized by Steris to determine radiation dose, which may 

or may not have been considered and understood by Steris’s customers. On July 14, 2014, 

Steris responded (ADAMS Accession No. ML14197A113) to the NRC inspection report and 

detailed its corrective actions, which were largely focused around ensuring the accurate 

communication of uncertainties in its process for any future work. 

Subsequent to identification of this issue, and since Steris has been a service supplier for a 

large portion of irradiation services for nuclear safety-related components, an industry group 

was formed to work with Steris, as necessary, to determine the broad scope of the issue. On 

April 27, 2015, Steris released a position paper (ADAMS Accession No. ML15170A147) that 

more thoroughly examined the previously-identified issues and provided a refined estimate of 

the maximum error (radiation dose applied that was less than requested) for any previous 

components irradiated at the Steris Whippany facility. In that position paper, Steris stated that it 

had recalculated the overall potential variability in the irradiation process to be approximately 

9.6 percent for most applications, and to be 11.8 percent for components processed at Steris in 

the ceiling location within their irradiation cell between October 19, 2007, and April 28, 2014. In 

June of 2015, the Nuclear Utility Group on Equipment Qualification, in collaboration with the 

Institute of Electrical and Electronics Engineers (IEEE), released an Industry Guidance Position 

Paper (ADAMS Accession No. ML15170A148), which provides an aid to utilities faced with 

responding to the subject issues. While the NRC has not performed a formal review of this 

document, it appears to provide useful supplemental information that could be used in response 

to this issue. 

BACKGROUND

The regulations in 10 CFR 50.49, “Environmental Qualification of Electric Equipment Important 

to Safety for Nuclear Power Plants,” state that each item in this category must be qualified either 

by type tests or a combination of type tests and analyses. NRC Regulatory Guide (RG) 1.89, 

Revision 1, “Environmental Qualification of Certain Electric Equipment Important to Safety for 

Nuclear Power Plants,” dated June 1984, endorses IEEE 323-1974, “IEEE Standard for 

Qualifying Class IE Equipment for Nuclear Power Generating Stations,” with some exceptions, 

as one method to comply with 10 CFR 50.49. Included within 10 CFR 50.49, and also 
IN 2015-12 

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addressed by RG 1.89 and IEEE 323, is a consideration of the effects of radiation on the 

components being qualified. Specifically, 10 CFR 50.49 states, in part, that: 

The radiation environment must be based on the type of radiation, the total dose 

expected during normal operation over the installed life of the equipment, and the 

radiation environment associated with the most severe design basis accident 

during or following which the equipment is required to remain functional, 

including the radiation resulting from recirculating fluids for equipment located 

near the recirculating lines and including dose-rate effects. 

Consequently, for a component to be considered qualified for its application, licensees must 

evaluate the component’s ability to perform after being subjected to a radiation dose 

commensurate to what the component would be expected to receive once installed in the 

reactor facility. In most cases, the radiation dose includes a dose related to normal and 

abnormal operations, as well as a dose related to an accident. 

The regulations in 10 CFR 50.49 also require that margins be included to account for 

unquantified uncertainty in the qualification process, such as the effects of production variations 

between tested and production components, as well as inaccuracies in test instrumentation. 

RG 1.89, Revision 1, states that the suggested margin values in Section 6.3.1.5 of 

IEEE 323-1974—as applied to radiation dose—are acceptable for meeting the 10 CFR 

50.49(e)(8) margin requirements. 

In addition, Criterion 4, “Environmental and dynamic effects design bases,” of the General 

Design Criteria contained in Appendix A to 10 CFR Part 50, requires that all structures, 

systems, and components important to safety be designed to accommodate the effects of and 

to be compatible with the environmental conditions associated with normal operation, 

maintenance, testing, and postulated accidents. Consequently, the issues identified in this IN 

might also apply to some non-electrical equipment not covered under the scope of 10 CFR 

50.49 (e.g., certain important-to-safety mechanical equipment, containment coatings, etc.). 

DISCUSSION 

The issues described above associated with the irradiation of nuclear components at Steris 

span many years, beginning since the opening of its Whippany facility in 1984. In most cases, 

Steris was not a direct service supplier to the nuclear utilities themselves, and nuclear utilities 

may not have been notified directly by their suppliers regarding the subject issues. While Steris 

notified its direct customers as required by 10 CFR Part 21, some of Steris’s customers that 

were originally responsible for the qualification of the equipment and components in question 

are no longer in business or no longer maintain nuclear quality assurance programs. 

Also, often times the radiation dose requirements provided by Steris’s customers were not 

nuclear power plant specific; therefore, the effect of the errors in irradiation on each 

component’s qualification is unknown. With respect to radiation, IEEE 323-1974 states that a 

margin of 10 percent of the accident dose should be used during the qualification process to 

account for uncertainties associated with variations in commercial production, inaccuracies in 

test equipment, and reasonable errors in defining satisfactory performance. 
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CONTACT 

This IN requires no specific action or written response. Please direct any questions about this 

matter to the technical contact listed below or the appropriate Office of Nuclear Reactor 

Regulation (NRR) or Office of New Reactors (NRO) project manager. 

/RA/ /RA/ 

Michael C. Cheok, Director Lawrence E. Kokajko, Director 

Division of Construction Inspection Division of Policy and Rulemaking 

 and Operational Programs Office of Nuclear Reactor Regulation 

Office of New Reactors 

Technical Contact: Jeffrey Jacobson, NRO 

 301-415-2977 

 E-mail: Jeffrey.Jacobson@nrc.gov 

 Nicholas Savwoir, NRO 

 301-415-0256 

 E-mail: Nicholas.Savwoir@nrc.gov 

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

http://www.nrc.gov, under NRC Library. 
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CONTACT 

This IN requires no specific action or written response. Please direct any questions about this 

matter to the technical contact listed below or the appropriate Office of Nuclear Reactor 

Regulation (NRR) or Office of New Reactors (NRO) project manager. 

/RA/ /RA/ 

Michael C. Cheok, Director Lawrence E. Kokajko, Director 

Division of Construction Inspection Division of Policy and Rulemaking 

 and Operational Programs Office of Nuclear Reactor Regulation 

Office of New Reactors 

Technical Contact: Jeffrey Jacobson, NRO 

 301-415-2977 

 E-mail: Jeffrey.Jacobson@nrc.gov 

 Nicholas Savwoir, NRO 

 301-415-0256 

 E-mail: Nicholas.Savwoir@nrc.gov 

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

http://www.nrc.gov, under NRC Library. 

ADAMS Accession No.: ML15215A502 TAC MF6471 

OFFICE Tech Editor NRO/DCIP/EVIB NRO/DCIP/EVIP/BC NRR/DE/EEB/BC RES/DE/ICEEB 

NAME JDougherty JJacobson RRasmussen JZimmerman RSydnor 

DATE 8/12/15 10/13/15 10/19/15 10/13/15 10/16/15 

OFFICE NRR/PGCB/LA NRR/PGCB/PM NRR/PGCB/BC NRO/DCIP/D NRR/PGCB/DD 

NAME ABaxter BHarris SStuchell MCheok AMohseni 

DATE 10/21/15 10/19/15 10/21/15 11/12/15 11/12/15 

OFFICE NRR/DPR/D 

NAME LKokajko 

DATE 11/ 20 /15 

OFFICIAL RECORD COPY