Information Notice 2016-12, Regarding Potential Absence of Required Lock Washers in BSI Instruments, Inc. LB 7400 Series Fixed Gauges
| ML16217A237 | |
| Person / Time | |
|---|---|
| Issue date: | 10/20/2016 |
| Revision: | 0 |
| From: | Collins D S Office of Nuclear Material Safety and Safeguards |
| To: | |
| Valentin-Rodriguez C | |
| References | |
| IN-16-012 | |
| Download: ML16217A237 (4) | |
ML16217A237 October 20, 2016 NRC INFORMATION NOTICE 2016-12: POTENTIAL ABSENCE OF REQUIRED LOCK WASHERS IN BSI INSTRUMENTS, INC. LB 7400 SERIES FIXED GAUGES
ADDRESSEES
All U.S. Nuclear Regulatory Commission (NRC) specific and general fixed gauge licensees and service provider All Agreement State Radiation Control Program Directors and State Liaison Officer
PURPOSE
The NRC is issuing this Information Notice (IN) to alert addressees of the potential absence of a required lock washer between the source assembly and source holder in BSI Instruments, In LB 7400 Series density fixed gauge The absence of the required lock washer may cause the source to become dislodged during us Recipients should review the information contained in this IN for applicability to their facilities and consider taking appropriate action, if necessar However, the information conveyed in this IN is not a new NRC requirement; therefore, no specific action or written response is require The NRC is providing this IN to the Agreement States for information and distribution to their licensees, as appropriat DESCRIPTION OF CIRCUMSTANCES Event 1 In December 2009, an NRC licensee encountered high radiation levels around a BSI Instruments, Inc. (formerly Apgee Corporation) Model LB 7440-D density fixed gauge (LB 7400 Series), while the licensee was attempting to relocate the gaug The gauge contained a GBq (150 mCi) cesium-137 sourc The radiation field was not reduced when a radiation worker moved the shutter to the closed positio The worker retreated from the area within 2 minute Upon removing the source head, a service engineer discovered that the source capsule had become unscrewed from the source holder and had fallen into a cylindrical hole intended to provide a path for the radiation bea The service engineer also noticed that a lock washer, required between the source and the source holder, was absen The source was removed and placed inside a new source hea The root cause of the event was failure of the gauge manufacturer to install a required lock washer in the fixed gaug The licensee identified 35 additional gauges that were missing the required lock washer (but had not experienced source capsule detachment or any other malfunctions). A public dose assessment for workers in the area determined that six nonradiation workers received estimated doses ranging from 1.09 to 1.46 mSv (109 to 146 mrem), in excess of the 1 mSv (100 mrem) regulatory limit for members of the publi Event 2 In February 2016, an Agreement State licensee discovered in its facility a BSI Instruments, Inc. fixed gauge Model LB 7442-D (LB 7400 Series), containing 1.1 GBq (30 mCi) of cesium-137, with the shutter stuck in the open positio The manufacturer evaluated the gauge, identified that the operating rod had been sheared in half, and attributed the malfunction to corrosion buildup on the brass shutter shaf However, during repairs, the service engineer for the manufacturer noted that the lock washer between the source holder and the source was missin The manufacturer stated that the missing lock washer could result in the source capsule coming loose due to vibration of the sourc Other fixed gauges at the facility were inspected and were determined to be missing the required lock washe The lock washers were installed in all the affected gauge DISCUSSION Although the root causes of the above events are different, they share the similar trait of missing lock washer During use, a Model LB 7400 Series gauge can experience vibration or temperature fluctuations that shift its source out of its shielded position within the source housin Also, if this gauge is installed in a vertical orientation, gravity may act upon the source capsule and cause the source to fall to the bottom plate of the gaug Lock washers are required because they secure the sources in their installed positions within the source housin This prevents the occurrence of unnecessary personnel exposure, as is illustrated by Event The above events suggest that licensees who possess Model LB 7440 Series gauges are likely to encounter missing lock washer For LB 7400 Series fixed gauges, a lock washer should be installed between the source assembly and source holder, as described in the gauge's Sealed Source and Device Registry, NR-0112-D-811-B, which has been superseded by TN-1031-A-101- Therefore, licensees who decide to perform routine maintenance on their gauges should exercise caution because of the possibility that some of their gauges may be missing the required lock washer Licensees may wish to consider having a qualified service provider verify the installation of the lock washe Licensees should exercise caution prior to performing maintenance on their fixed gauges and should conduct radiation surveys to confirm that sources are in their shielded positio BSI Instruments, Inc. addressed this issue by requesting and obtaining an amendment to their Sealed Source and Device Registration Certificate (NR-0112-D-811-B), requiring that lock washers be installed in certain model The current distributor, Berthold Technologies U.S.A, LLC, is aware of this issue in older models distributed by BSI Instruments, Inc. and is actively working with customers to refurbish older gauge The lock washer is incorporated into the design of all models distributed by Berthold Technologies U.S.A, LLC, as evidenced in their Sealed Source and Device Registration Certificate, TN-1031-D-101- As a reminder, installation, replacement, removal from service, and disposal of sealed sources used in the LB 7400 Series fixed gauges shall only be performed by the device manufacturer, or other persons authorized by an Agreement State or U.S. Nuclear Regulatory Commission specific licens Furthermore, licensees are reminded that Title 10 of the Code of Federal Regulations (10 CFR) 30.50(b)(2) requires a report within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> after the discovery of any event in which equipment is disabled or fails to functio A 30-day followup report is required by 10 CFR 30.50(c)(2).
CONTACT
This notice requires no specific action or written respons For questions, please contact the technical contact belo /RA/ Daniel S. Collins, Director Division of Material Safety, State, Tribal and Rulemaking Programs Office of Nuclear Material Safety and Safeguards
Technical Contact:
Celimar Valentin-Rodriguez, NMSS Phone: (301) 415-7124 E-mail: Celimar.Valentin-Rodriguez@nrc.gov Note: NRC generic communications may be found on the NRC public Web site, http://www.nrc.gov, under "NRC Library" > "Document Collections" Furthermore, licensees are reminded that Title 10 of the Code of Federal Regulations (10 CFR) 30.50(b)(2) requires a report within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> after the discovery of any event in which equipment is disabled or fails to functio A 30-day followup report is required by 10 CFR 30.50(c)(2).
CONTACT
This notice requires no specific action or written respons For questions, please contact the technical contact belo /RA/ Daniel S. Collins, Director Division of Material Safety, State, Tribal and Rulemaking Programs Office of Nuclear Material Safety and Safeguards
Technical Contact:
Celimar Valentin-Rodriguez, NMSS Phone: (301) 415-7124 E-mail: Celimar.Valentin-Rodriguez@nrc.gov Note: NRC generic communications may be found on the NRC public Web site, http://www.nrc.gov, under "NRC Library" > "Document Collections"
ADAMS Accession No. ML16217A237 *Via e-mail OFFICE MSTR/MSLB MSTR/MSLB MSTR/MSLB *MSTR/MSEB*QTE MSTR NAME CValentin-Rodriguez LSepulveda for THerrera HGonzalez AMcIntosh CHsu DCollins DATE 08/04/16 08/04/16 08/05/16 08/02/16 08/25/16 10/20/16 OFFICIAL RECORD DOCUMENT