|LOSS OR DEGRADATION OF SAFETY ITEMS
"[On February 11, 2019 at 1519 MST,] it was discovered that the calibration certificates for Measuring and Testing Equipment (M&TE) used to perform temperature trip IROFS [Items Relied On For Safety] surveillances, only had 1 set of calibration data. The instruments have an internal temperature sensor and an external input for temperature. Previously, the IROFS surveillances for IROFS 1, 2, 4, 5, 11, 43, C15, and C16 were performed using the external input.
"An external vendor, that performs the calibration for this M&TE, confirmed that the calibration had only been performed on the internal temperature sensor. This issue of how ATC-1 and ATC-2 (Jofra brand dry-block temperature calibrators) were calibrated is not currently an issue, as UUSA [URENCO USA] now only uses the Jofras as a heat source and uses a separately calibrated resistance temperature detector (RTD) and display for IROFS surveillances.
"Further investigation findings showed that a number of UF6 stations had not had their scheduled surveillance with the new method using a separately calibrated RTD. In total, 25 stations had their required annual IROFS surveillances performed with M&TE equipment which used an input that was not properly calibrated.
"The plant is in a safe condition."
The licensee will be contacting Region II.