United States Nuclear Regulatory Commission - Protecting People and the Environment

U.S. Nuclear Regulatory Commission

Lead Shielding Attached to Safety Related Systems Without 10 CFR 50.59 Evaluations

HPPOS-091 PDR-9111210180

Title: Lead Shielding Attached to Safety Related Systems

Without 10 CFR 50.59 Evaluations

See IE Information Notice No. 83-64 entitled as above and

dated September 29, 1983. This document informs licensees

that failure to analyze for possible seismic and structural

effects, both dynamic and static, from lead shielding on

safety-related systems constitutes an unreviewed safety

question. In addition to this document, see IE Circular

No. 80-18, "10 CFR 50.59 Safety Evaluation for Changes to

Radioactive Waste Treatment System" (see HPPOS-086).

During a routine inspection, an NRC inspector noted that

portions of safety-related piping in the primary auxiliary

building of a power station was covered with lead

shielding. Discussions with the plant engineering staff

revealed that licensee safety evaluations supporting this

modification had not been done. The licensee had neither

formal control mechanisms to govern the installation, use,

and accounting of the temporary shielding, nor records to

document the dates and locations of the shielding

installations. The shielding was placed on plant systems

during a period when high fuel element failure rates led to

increased radiation fields throughout the plant. After a

refueling outage, the licensee began a program to identify

and remove temporary shielding installed on systems inside

the containment building, but failed to do this in other

plant areas. Improvements in the maintenance and design

program would have prevented shielding installation without

required 10 CFR 50.59 evaluations.

Failure to analyze for possible seismic / structural effects

(both dynamic and static) of lead shielding on

safety-related systems constitutes an unreviewed safety

question. In regards to the above situation,

safety-related systems were modified with additional

shielding without supporting engineering evaluations to

ensure system operability under design-basis event

conditions. Although it is focused on radioactive waste

treatment systems, IE Circular No. 80-18, "10 CFR 50.59

Safety Evaluation for Changes to Radioactive Waste

Treatment System", provides general guidance and

clarification regarding the requirements of 10 CFR 50.59

(see HPPOS-086).

Regulatory references: 10 CFR 50.59

Subject codes: 5.3, 8.5

Applicability: Reactors

Page Last Reviewed/Updated Thursday, March 29, 2012