IR 05000224/1980002
| ML19321A432 | |
| Person / Time | |
|---|---|
| Site: | Berkeley Research Reactor |
| Issue date: | 06/09/1980 |
| From: | Book H, Wenslawski F, Yuhas G NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | |
| Shared Package | |
| ML19321A428 | List: |
| References | |
| 50-224-80-02, 50-224-80-2, NUDOCS 8007230355 | |
| Download: ML19321A432 (4) | |
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JUN e 1380
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U. S. NUCLEAR REGUIATORY C0!cilSSION OFFICE OF INSPECTION AND ENFORCEMENT
REGION V
Report No.
50-224/80-02 Docket No.
50-224 License No.
R-101 Safeguards Group Licensee:
University of California Berkeley, California 94720 i
Facility Name:
TRIGA - Mark III Inspection at:
Berkeley, California Inspection conducted:
May 16, 1980 Inspectors:
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G. P.
as, Radiation Specialist Date ' Signed
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Date Signed Y)Its W b f YO
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Approved by:
__. Wenslaw ki, Chief, Reactor Radiation Safety Secti6n Efate signed i
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Approved By:
H. E. Book, Chief, Fuel Facility and Materials Safety Date Signed Summary:
Inspection on May 16, 1980 (Report No. 50-224/80-02).
Areas Inspected: Special announced inspection in response to an unplanned accidential release of airbore radioactive materials.
The inspection involved 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> on site by one NRC inspector.
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Results: No item of noncompliance was identified.
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4 RV Form 219 (2)
8007230355
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I DETAILS 1.
Persons Contacted
- T. Lim, Reactor Supervisor
- G. Little, Reactor Health Physicist
- Denotes those attending the exit interview.
2.
Description of Release As part of a class experiment, the licensee had irradiated a 40 milligram uranium sample in the reactor.
Shortly after the sample was returned via the pneumatic sample transfer system (rabbit system) to the receiving station within a ventilation hood, the facility noble gas stack monitor alarmed. Upon investigation, the licensee discovered that the sealed polyethylene sample holder had cracked, thereby releasing the trapped
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fission gases. This occurred at approximately 3:00 PM on May 15, 1980.
The licensee performed an initial evaluation of the fission gas release and concluded that the radioiodine released resulted in a concentration ten times the appropriate values specified in 10 CFR 20 Appendix B Table II at the ventilation stack when averaged over a 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> period.
10 CFR 20.403 " Notifications of Incidents" requires that the licensee notify the NRC Regional Director within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of the release of radioactive material in concentrations which, if averaged over a period
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of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, exceed 500 times the limits specified for such materials in Appendix B, Table II.
This release was estimated at one fiftieth of this value, however, the licensee's Technical Specifications section 6.7, "Reportir.g Requirements" states: a report will be submitted to the NRC Region V Office of Inspection and Enforcement within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of:
"Any accidental release of radioactivity above permissible limits in unrestricted areas whether or not the release resulted in property damage, personal injury, or exposure;"
Region V was notified of this occurrence at 12:15 PM May 16,1980.
3.
Review of Release An NRC inspector visited the facility on the afternoon of May 16, 1980 to review the release with licensee representatives.
The following observations were made.
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a.
flo students or facility members involved in this experiment received a measurable personnel contamination or detectable dose associated with this release.
The licensee had the personnel dosimeter (film badge) of the individual working nearest the ventilation hood read. This individual's dose was reported as less than the minimum detectable level of the film badge (cf 20 mrem),
b.
The building stack monitor responded to the release.
Interpretation of the stack monitor recorder indicates the major portion of the release occurred over a five minute period.
The transient lasted about 70 minutes from the initial indication of an increase until the stack monitor returned to the background level.
c.
The four environmental thermoluminescent dosimeters located ontop of the building did not indicate a dose above the minimum detectable level. The minimum detectable level for the dosimeter is 2 mrem.
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d.
The initial estimate of the radioiodines released was overly
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conservative. The licensee performed a detailed quantitative evaluation of the release and reported the result to.NRC Region V by telephone on May 29, 1980. These valves are noted in the
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table below.
10 CFR 20 Concentration Concentration Appendix B at Stack at Stack Table II Permissible
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Total Act.
Averaged Averaged Concentration for Released over 5 min.
over 70 min.
Continuous Exposure
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Isotope uCi uCi/cc uC1/cc uCi/cc
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I-132 5.
4.3 E-10 3.1 E-ll 3E-9 I-133 44.4 3.4 E-9 2.4 E-10 4 E-10 1-134 477.5 3.6 E-8 2.6 E-9 6E-9 I-135 233 1.8 E-8 1.3 E-9 lE-9
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The licensee has calculated the noble gas released to be 31.5 millicuries. This activity averaged over the 5 minute period results in a concentration of 8E-6 uCi/cc, averaged over 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> results in a concentration of 2.6E-8 uCi/cc. The applicable 10 CFR 20 Appendix B Table II value for these isotopes is IE-7 uCi/cc.
The amount of radioactivity released was a small fraction of the limits expressed in 10 CFR 20.106.
e.
The release was apparently caused by failure of the heat sealed polyethylene sample envelope. The licensee has not determined the exact cause of the failure. Additional review of the sealing process is being performed by the licensee.
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4.
Exit Interview The inspector met with licensee representatives (denoted in Paragraph 1)
at the conclusion of the inspection on May 16, 1980. The inspector summarized the scope and findings of the inspection.
The inspector indicated that the licensee's final evaluation of this release will be reviewed in a subsequent inspection (50-224/80-02-01).