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Category:REPORTABLE OCCURRENCE REPORT (SEE ALSO AO LER)
MONTHYEARML20070B4721994-06-21021 June 1994 Ro:On 940617,during pre-start Checks for Gas Cooled Mineral Irradiation Facility Checklist,Discovered That Experiment Scram Bypass Switch Position Check Had Not Been Performed Correctly for 3 Days.Caused by Supervisor Error ML20101N5941992-07-0101 July 1992 Special Rept:On 920615,briefly Unidentified High Radiation Area Noted During Reactor Startup.Caused by Human Error. Self-critical Evaluation Conducted & Controls in Place to Prevent Reccurrence ML20108B8341984-11-0101 November 1984 Ro:On 841002,high Radiation Hot Spot Discovered at Ground Level Along Outside Wall of Reactor Room.Caused by Experiment.Personnel Removed Radiation Source & Relocated Shield Cask.Program Revised ML20076F3341983-06-0909 June 1983 Ro:On 830530,reactor Shut Down When Shutdown Margin During Criticality Violated Tech Specs.Caused by Difference in Partial Fuel Element Added on 830525.Reactor Shut Down 830606.Control Rods Recalibr.Procedures Changed 1994-06-21
[Table view] Category:TEXT-SAFETY REPORT
MONTHYEARML20204G5541998-12-31031 December 1998 Univ of Virginia Reactor Facility 1998 Annual Rept ML20198J2431998-12-21021 December 1998 Safety Evaluation Supporting Amend 24 to License R-66 ML20236Y4511998-07-31031 July 1998 Revised Operator Requalification Program ML20236K4861998-07-0707 July 1998 Safety Evaluation Supporting Amend 8 to License R-123 ML20249A5961998-06-15015 June 1998 Safety Evaluation Supporting Amend 23 to License R-66 ML20217G6391997-12-31031 December 1997 Univ of Virginia Reactor Facility Annual Rept,1997 ML20137B3471996-12-31031 December 1996 Univ of VA Reactor Facility Annual Rept for 1996 ML20138H1171996-11-19019 November 1996 Univ of Virginia Nuclear Reactor Facility 1996 Emergency Preparedness Exercise Scenario for 961119 ML20101E0311995-12-31031 December 1995 Univ of VA Reactor Facility 1995 Annual Rept ML20093L1171995-10-31031 October 1995 Revised Sar,Incorporating Proposed Section 9.20.8 ML20093C7501995-10-31031 October 1995 SAR for Low-Enriched U Fueled Univ of VA Reactor ML20095F3031995-10-10010 October 1995 Univ of VA Nuclear Reactor Facility 1995 Emergency Preparedness Drill Scenario for 951108 ML20081K4961994-12-31031 December 1994 Univ of VA Reactor Facility 1994 Annual Rept ML20077C3881994-10-18018 October 1994 Univ of VA Nuclear Reactor Facility 1994 Emergency Preparedness Drill Scenario for 941122 ML20076F9091994-10-13013 October 1994 HEU to LEU Conversion Rept ML20072R0081994-08-26026 August 1994 Part 21 Rept Re Area Monitoring Sys Consisting of Model Adm 600A(V10) Readout Module & GP-100C Geiger-Muller Detector Supplied by Nuclear Research Corp.Replacement Circuit Card Assemblies Provided to Univ of VA ML20071L8551994-07-28028 July 1994 Part 21 Rept Re Defect in Basic Component Purchased from Nuclear Research Corp.Rest of Ltr Follows Listing of Required Topics as Stated in Paragraph 21.21 Section 4 ML20070B4721994-06-21021 June 1994 Ro:On 940617,during pre-start Checks for Gas Cooled Mineral Irradiation Facility Checklist,Discovered That Experiment Scram Bypass Switch Position Check Had Not Been Performed Correctly for 3 Days.Caused by Supervisor Error ML20064N4511993-12-31031 December 1993 University of VA Reactor Facility 1993 Annual Rept ML20044H0671993-05-26026 May 1993 Ro:On 930428,inadvertent Mod to Reactor Console Resulted in Operation of Reactor for Period of About Five & One Half H W/Several Protective Scrams,Per TS Not Operable.Minor & temporary,non-safety Sys Related Changes Recommended ML20044D7311993-05-12012 May 1993 Fourteen-Day Rept of Reportable Event Re Inadvertent Mod of Univ of Virginia Reactor Console. ML20101N5941992-07-0101 July 1992 Special Rept:On 920615,briefly Unidentified High Radiation Area Noted During Reactor Startup.Caused by Human Error. Self-critical Evaluation Conducted & Controls in Place to Prevent Reccurrence ML20097E0431992-06-0404 June 1992 Proposed Operator Requalification Program for Univ of Virginia Reactor Facility ML20094M4301991-12-31031 December 1991 Univ of Virginia Reactor Facility Annual Rept,1991. W/ ML20070R6011990-12-31031 December 1990 Univ of Virginia Reactor Facility 1990 Annual Rept. W/ ML20059E8991990-08-29029 August 1990 Safety Evaluation Supporting Amends 19 & 7 to Licenses R-66 & R-123,respectively ML20012B0741990-02-28028 February 1990 Decommissioning Plan for Univ of Virginia 100-Watt Cavalier Reactor & Application for Termination of Ol. ML19327C1561990-01-31031 January 1990 Effective Diffusion Theory Cross Sections for Univ of Virginia Control Rods. ML20042D7581989-12-31031 December 1989 Univ of Virginia Reactor Facility Annual Rept 1989. W/ 900307 Ltr ML19327C1531989-11-30030 November 1989 SAR for Low Enriched U Fueled,Univ of Virginia Reactor. ML19327C1551989-07-31031 July 1989 Neutronic Analysis for Univ of Virginia Reactor High Enrichment U to Low Enrichment U Conversion Project. ML20247H2391989-07-20020 July 1989 Safety Evaluation Supporting Amends 18 & 6 to Licenses R-66 & R-123,respectively ML20246L8071989-03-15015 March 1989 Safety Evaluation Supporting Amend 5 to License R-123 ML19327C1541989-01-31031 January 1989 Design Optimization of Low Enrichment,Univ of Virginia Nuclear Reactor. ML20247G8351988-12-31031 December 1988 Univ of Virginia Reactor Facility Annual Rept 1988 ML20151U0821988-04-25025 April 1988 Safety Evaluation Supporting Amend 16 to License R-66 ML20148N6491988-03-31031 March 1988 Proposal for Conversion of Univ of VA Nonpower 2 Mwt Univ of VA Research Reactor from Highly Enriched U to Low Enriched U Fuel ML20148D7991987-12-31031 December 1987 Reactor Facility Annual Rept 1987 ML20137K8611986-01-13013 January 1986 Annual Operating Rept for 1985 ML20129F2401985-05-31031 May 1985 Safety Evaluation Report Related to the Renewal of the Operating License for the CAVALIER Training Reactor at the University of Virginia.Docket No. 50-396.(University of Virginia) ML20106H0141985-01-24024 January 1985 Annual Rept of Operations of Univ of Virginia Reactor & CAVALIER Reactor During 1984 ML20137E2941984-12-31031 December 1984 Addendum to 1984 Annual Rept ML20108B8341984-11-0101 November 1984 Ro:On 841002,high Radiation Hot Spot Discovered at Ground Level Along Outside Wall of Reactor Room.Caused by Experiment.Personnel Removed Radiation Source & Relocated Shield Cask.Program Revised ML20092M2891984-06-22022 June 1984 Updated SAR in Support of License R-123 Renewal ML20086S1681984-02-16016 February 1984 Annual Operating Rept for 1983 ML20024C0461983-06-30030 June 1983 Updated RO Re 830525 Low Shutdown Margin During Criticality. Initially Reported on 830609.Caused by Change in Control Rod Reactivity Worth Curves Due to Fuel Burnup.Procedures for Shutdown Margin & Reactivity Worth Determination Rewritten ML20076F3341983-06-0909 June 1983 Ro:On 830530,reactor Shut Down When Shutdown Margin During Criticality Violated Tech Specs.Caused by Difference in Partial Fuel Element Added on 830525.Reactor Shut Down 830606.Control Rods Recalibr.Procedures Changed ML20070P0581983-01-0505 January 1983 Annual Rept of Operations,1982 ML20041F4651982-03-11011 March 1982 QA Program for Procurement,Use,Maint & Repair of Packaging Used to Transport Spent Fuel,Radioactive Matl & Pu ML20038B2591981-08-26026 August 1981 Univ of VA Reactor (Uvar). 1998-07-07
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UNIVFRSITY OF VIRGINIA SCHOOL OF ENGINEERING AND APPLIED SCIENCE w C H AR LOTTESVILLE. 22901 CEPARTMENT OF NUCLEAR ENQiN EERIN G AND ENGINEERING ' PHYSICS TELEPHONE: 504-924-7136 EEACTOR FACILITY June 9, 1983 CS Mr. James P. O'Reilly U. S. Nuclear Regulatory Commission c=
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Dear Mr. O'Reilly:
This is to inform you as required by Section 6.4.2 of the Technical Specifications for the UVAR reactor, Facility License R-66, Docket No. 50-62 of a reportable occurrence.
Technical Specification 3.1 requires a shutdown margin of greater than 0.4% Ak/k with the highest worth rod fully withdrawn and a cold, xenon free condition with secured experiments in place. In violation of this requirement, the UVAR was operated approximately 16 hours1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br /> and 25 minutes with a shutdown margin of approximately 0.2% Ak/k. This operation did not pose a threat to the public health and safety as the total shutdown margin with all rods inserted was approximately 2.6% Ak/k without xenon. .
On Monday, May 23, 1983 the UVAR reactor was started and the shutdown margin measured to be 1.00% Ak/k. On Wednesday, May 25, 1983 the reactor was shutdown to test a new experiment. The experiment had been previously measured to be worth -0.31% Ak/k, In attempting to restart the reactor, the negative xenon reactivity could not be overcome and the reactor was shutdown. A check of two previous loadings indicated that a partial fuel element added to the periphery of the core was worth +0.6% Ak/k. It was decided to add a partial fuel element and prior to startup, the shutdown margin was calculated as follows:
1.00% (on 5-23-83)
+0.07% (Burn-up from 5-23-83 to 5-25-83)
+0.31% (worth of experiment)
-0.6% (positive worth of partial fuel element) 0.78% (new shutdown margin) l The reactor was then started and operated for approximately 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />. The shutdown margin with the highest worth rod fully withdrawn plus the xenon in the reactor had a reactivity worth of approximately 2.9% Ak/k. The reactor was shutdown after approximately 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> operation and the experiment removed. The shutdown margin was then estimated to be (0.78 - 0.31) Ak/k or 0.47% Ak/k. Since
- OFFICIALC 8306140005 830609 DR ADOCK 05 %-
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1 Letter to James P. O'Reilly l June 4, 1983 ,
Page 2 1 this is within the Technical Specification limits, it was agreed to recommence operation. The reactor was started at 7:00 p.m. on May 25, 1983 and operated at two megawatts until 11:25 a.m. on Thursday, May 26 or about 16 hours1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br /> and 25 minutes. The reactor remained shutdown from 11:25 a.m. on May 26, 1983 until Monday afternoon, May 30, 1983 at 5:30 p.m. In preparation for an experinental run, the staff removed a graphite element worth +0.16% Ak/k from the front row of the grid plate. The reactor was started to do a reactivity check prior to loading the experiment. When the reactor achieved criticality the shutdown margin was measured to be 0.35% which would have been in violation of Section 3.1 of the Technical Specifications if the reactor had been operated at powers above 1 kw. The reactor was shutdown immediately and the Reactor Supervisor was notified by telephone (the Director of the Reactor Facility was out of town).
After a series of measurements of the reactivity worth of several experiments and graphite elements, an experiment was removed from the reactor core region and the shutdown margin was measured to be 0.71%. The reactor war then taken to a 2 megawatt power level at 9:48 p.m. on bhy 30, 1983.
An investigation by the Reactor Starf on Monday, May 30, and Tuesday, May 31, 1983 revealed that the partial fuel element added to the reactor on May 25, 1983 was worth 0.83% Ak/k instead of 0.6% as originally estimated. Thus, during the 16 hour1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br /> and 25 minute run from 7:00 p.m. Wednesday, May 25, 1983 until 11:25 a.m., Thursday, May 26, 1983, the reactor was operated with a clean, cold, shutdown margin of 0.19% Ak/k. Mr. J. P. Farrar, Reactor Supervisor placed a call to your office at approximately 2:40 p.m. on Tuesday, May 31, 1983 and Mr.
Caudic Julian was informed of the incident. Mr. Austin Hardin of your office called our facility twice on Wednesday, June 1,1983 for more information and informed us that two inspectors from the North Anna plant would be at our facility on Thursday, June 2, 1983 to investigate the incident. Messrs. M. Shymlock and J. Leahman of your office vere at our facility on Thursday and Friday, June 2nd and 3rd to investigate the incident.
The UVAR reactor was shutdown on June 6,1983. The control rods are currently being recalibrated and the experiment reactivity worths remeasured. The reactor will not be operated at power again until procedure changes are made concerning shutdown margin and experiment handling and reviewed and approved by our Reactor Safety Committee. Your office will be notified before the reactor is operated at power.
The incident will be reviewed by our Reactor Safety Committee on Thursday, June 9, 1983.
Sincerely,
! J. S. Brenizer, Jr., Director l UVA Reactor Facility JSB:ph l cc: T. G. Williamson l
J. P. Farrar 1 Reactor Safety Committee 1
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