ENS 48694
ENS Event | |
|---|---|
20:07 Jan 16, 2013 | |
| Title | Leaking Ni-63 Source |
| Event Description | The following was excerpted from email received from NASA Ames:
The source in question is a 5 mCi solid Ni-63 beta foil source located inside a Valco electron capture detector that was previously used for gas chromatograph. The leaking source in question was not in service at the time the contamination was found. The source was in storage awaiting disposal to a licensed facility. The radiation safety officer identified elevated contamination results for the source mentioned above during his review of the semi-annual sealed source inventory and leak test report which was conducted by the former health physics contractor in December 2012. All contamination levels were well below the NRC contamination threshold of .005 micro Curie at that time. The RSO directed the former health physics contractor to take a follow-up survey to verify the counts begin detected were actually Ni-63, bag the source, perform a survey of the immediate area where the source was being stored awaiting disposal, and prepare a report documenting the follow-up report and isotope identification prior to his termination with the end of his company's contract on December 31, 2012. On January 15, 2013, the new contract Health Physicist for NASA Ames Research Center, conducted a follow-up survey and leak test for the 5 mCi Ni-63 source. On January 16 the RSO confirmed that approximately 0.162 micro Curie (~36,000 dpm) beta contamination was distributed on the exterior surface of the electron capture detector. This value is in excess of the allowable leakage of 0.005 micro Curie (11,100 dpm) of contamination. The cause of the leaking source is not certain at this time. The source is approximately 23 years old so its possible age played a factor. The source has been in storage for a researcher who no longer had funding to continue using them in his research. It is stored in the RSO's radioactive materials storage facility for the last 6 years. During storage, the leak tests for the source continued to be conducted and all semi-annual leak tests never revealed any leaking contamination from the internal source. No persons are expected to have received any dose or exposure to radioactive materials as a result of this event. Ni-63 is a weak beta emitter and not capable of penetrating the dead layer of skin if in contact with the skin and is thus not an external radiation hazard. A general area contamination survey was also conducted in the immediate vicinity of where the source was stored. Contamination levels were all found to be near background levels in all locations confirming that there is no contamination event for the storage facility. The device has been in storage in a locked cabinet with access only to the RSO and Health Physics contractor during the period in which the leaking occurred so this makes the possibility of inadvertent personnel contamination remote. Required procedure for performing sealed source leak tests is to always wear disposable impermeable gloves. This would have prevented any personnel contamination. |
| Where | |
|---|---|
| Nasa Ames Research Center Moffett Field, California (NRC Region 4) | |
| License number: | 01-07845-04 |
| Organization: | Nasa Ames Research Center |
| Reporting | |
| 10 CFR 30.50(b)(2), Licensed Material Protection Equipment Failure | |
| Time - Person (Reporting Time:+161.05 h6.71 days <br />0.959 weeks <br />0.221 months <br />) | |
| Opened: | Patrick Muldoon 13:10 Jan 23, 2013 |
| NRC Officer: | Charles Teal |
| Last Updated: | Jan 23, 2013 |
| 48694 - NRC Website | |
Nasa Ames Research Center with 10 CFR 30.50(b)(2) | |
WEEKMONTHYEARENS 486942013-01-16T20:07:00016 January 2013 20:07:00
[Table view]10 CFR 30.50(b)(2) Leaking Ni-63 Source 2013-01-16T20:07:00 | |