December 11, 2023 | Susan Napier-Sewell

Lessons Learned: High Noise Activity/Work

high noise

This DOE Lessons Learned statement is about high noise activity and noise level when working around a nuclear facility.

The first action is: Notify the Nuclear Facility Manager (NFM), when mowing, weed trimming, or high noise work is to be performed in an Immediate Evacuation Zone (IEZ) of a Nuclear Facility.

Next, the NFM will need to establish a Limiting Condition of Operation (LCO), prior to approving high noise work start in that area.

In the Lessons Learned incident, published by Fluor,* the NFM was not made aware of the mowing that was being performed in a non-nuclear facility footprint that encompassed part of their nuclear facility IEZ. A Technical Safety Requirement (TSR) was violated for not entering an LCO. DISCUSSION: A Dispatch work order (DW) was developed for mowing at the X-747F, Miscellaneous Material Storage Area.

The DW did not mention the proximity of the X-747F to the X-720 Maintenance Facility IEZ, or any requirements for performing high noise producing work inside an IEZ. When another contractor notified the Plant Shift Superintendent (PSS) to report mowing/weed trimming in an adjacent IEZ, the PSS discovered that they had not been notified by the NFM of the X-720 IEZ or the work group supervisor of the crew that was performing the mowing in the X-747F area that encompassed part of the X-720 IEZ.

Work was paused, and the alternate NFM of the X-720 IEZ was notified by the work group supervisor to determine if the mowing was in the IEZ. It was determined that the mowing activity at the X-747F did include part of the X-720 IEZ. ANALYSIS: Not all site personnel are knowledgeable or understand what the requirements are for working in an IEZ boundary or how they relate to Criticality Accident Alarm Systems (CAAS).

With the lack of physical boundaries of the IEZs, workers could not easily identify where the IEZ begins or ends. The safety alert discussing IEZ boundaries for nuclear facilities was not clear to the general plant population due to the alert not identifying the facilities where a nuclear facility IEZ encompassed all or part of another facility.

Additionally, two or more Facility Managers are not required to be contacted for work start approval for facilities that encompass an IEZ boundary. Work planning documents were not evaluated for impacts when the TSRs were revised to include mowing, weed trimming, or high noise producing work activities.

Resolution/recommended actions

• Paused work and placed the area in a safe configuration.

• Issued Stop Work for all FBP site work tasks requiring high noise evolutions that are not part of normal approved building operations and conducted in CAAS covered facilities or IEZ’s unless evaluated by the Cognizant System Engineer.

• Evaluate current training involving IEZ Boundaries/Working within an IEZ.

• Establish visible IEZ boundaries across plant-site.

• Issue site communications to heighten awareness of IEZ locations and requirements for performing work in an IEZ.

Content source/credit: DOEOpexShare 39609 “High Noise Activity within X-720 CAAS IEZ,” publisher: Fluor BWXT Portsmouth, Piketon, OH (Fluor BWXT).


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