The following information was provided by the
New Hampshire Radiological Health Section (
NHRHS) via email:
On August 2, 2023, Nylon Corporation of America (NYCOA) reported that a specifically-licensed fixed level gauge (Berthold, Serial No. 175-02-07) installed on the `Capro Recovery Unit' apparently failed a semi-annual detector test. The detector provides a remote indication of tank level and shutter position. In the absence of remote indication, shutter position can be noted visually. The gauge shutter is manually operated and performs as designed. Additional testing performed on August 3, 2023, verified the detector failure. NYCOA formally reported their findings to the NHRHS via email on August 3, 2023 at 1316 [EDT].
The fixed gauge (Berthold Model LB-300L) houses a 32.9 MBq (0.89 mCi) Co-60 source assayed on January 1, 2006. The current activity is calculated as 3.3 MBq (0.088 mCi). The gauge is affixed to a tank that is suspended about 9 feet above the process room floor. The location cannot be accessed without a ladder. The surrounding area contains process piping and is not normally occupied.
On August 4, 2023, at 0930, NHRHS inspectors arrived to perform a reactive inspection. As found, the level gauge shutter was closed and appropriately locked-out/tagged-out of service. The highest measured exposure rate was 0.327 mR/hour in contact with the gauge housing (shutter closed). At head height, below the gauge, the exposure rate was 0.010 mR/hr, which approximates normal background. A Ludlum 9DP ion chamber was utilized for these measurements.
There is no indication of personnel overexposure.
NYCOA stated that the Capro Recovery Unit has been offline for about five years and there are no near-term plans to bring it back online. NYCOA will investigate removal and disposal of the level gauge rather than repair the detector.
NMED Report Number: NH-23-0001