IR 05000123/1993004
| ML20058H502 | |
| Person / Time | |
|---|---|
| Site: | University of Missouri-Rolla |
| Issue date: | 12/06/1993 |
| From: | NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | |
| Shared Package | |
| ML20058H464 | List: |
| References | |
| 50-123-93-04, 50-123-93-4, NUDOCS 9312130096 | |
| Download: ML20058H502 (5) | |
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U.S. NUCLEAR REGULATORY COMMISSION .;
I REGION III i i
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Report No. 50-123/93004(DRSS) [
Docket No. 50-123 License No. R-79 Licensee: University of Missouri - Rolla j Facility Name: University of Missouri - Rolla Nuclear Reactor !
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Inspection At: Nuclear Reactor Facility, Rolla, Missouri 'l
Inspection Conducted: November 3-5, 1993 i
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Inspector: M MhMIA'd T. D. Reidinger g Date l l
Accompanying Personnel: S. Hill ;
M. Mendonca j
, i Approved By:( M h MP AO/4/4S Date ~ !
' ' M,#J. W. McCormick-Barger, Chief Radiological Programs Section 1 l t
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Inspection Summarv !
Inspection on Nnvember 3-5. 1993 (Report No. 50-123/93004(DRSS)) !
Areas Inspected: Announced reactive inspection to review the circumstances j concerning reactor operations with inoperable period instrumentation and '
- associated reactor protection features on October 26. 199 !
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Results: The event was the result of equipment failure. The duration of the j event was unnecessarily long due to personnel error resulting in one violation. The violation involved the operator not completely following 50P- .;
103, Reactor Startup, as required by Technical Specifications 6.3. A weakness !
was identified regarding a lack of understanding by the operator concerning !
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when to use applicable instrumentation to verify or confirm reactor period l parameters during transient reactor power condition l The licensee implemented strong corrective actions in both identifying and !
correcting the equipment hardware ceficiencies, and addressing the operator j proficiency issu ;
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9312130096 931206 PDR ADOCK 05000123 <
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DETAILS {
! Persons Contacted Li i
University of Missouri-Rolla !
- D. Bolon, Reactor Director (
- D. Freeman, Reactor Manager j
- B. Bonzer, Chief Electronics Technician l
- L. Pierce, Senior Secretary !
- M. McLaughlin, Senior Reactor Operator !
- T. K.houaja, Senior Reactor Operator ;
- Gajda, Vice Chancellor of Academic Affairs j
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- J. McCormick-Barger; Region Ill, Section Chief !
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- Denotes those present at the exi !
l The inspectors also interviewed other licensee personnel in various i
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departments in the course of the inspectio . General ;
I This inspection was conducted to review the circumstances involving the ;
loss of reactor period instrumentation which occurred on October 26, {
1993. The inspection included reviewingi applicable records and logs !
from the event; equipment / hardware; equipment discrepancy records; root !
cause analyses; and licensed operator training. In addition, the f inspectors interviewed operations personnel and a student; reviewed licensee corrective actions; and conducted a walk-through and human factors review of the event sequence from both a performance and- ,
operational perspectiv l Introduction On October 27, 1993, the NRC was notified that on October 26, 1993, the l University of Missouri-Rolla Research Reactor was started up and ;
inadvertently operated without reactor period instrumentation 'l functioning properly. The licensee subsequently confirmed that the j reactor period scram and period rod runback protective functions were
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also inoperable as a result of the malfunctio . License Event Report (92700)
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(Closed) LER 93-01: Operation of the Research Reactor with inoperable !
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reactor period instrumentatio On October 26, 1993, the research reactor was started up as a part of a ;
routine nuclear engineering class designed to provide students with a i
" hands-on" operational training opportunity (i.e., start-up, make power i level changes, and shut down the reactor). This was accomplished under ;
the supervision of a licensed operator on the reactor controi The l
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l instruc'.or (licensed reactor operator (RO)) and two students were' in the -
control room; a student performed the pre-startup checklist, including :
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conducting a response test of the period strip chart recorder, period meter and alarms. The pre-startup checklist was successfully completed ,
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at 1350 hours0.0156 days <br />0.375 hours <br />0.00223 weeks <br />5.13675e-4 months <br />. The period instrumentation responded properly during the pre-startup checklist, which included four separate tests on this !
instrument, and was verified by reviewing the period strip chart !
recorder. Start up of the reactor commenced at that time. Three power l 1evel increases were made with two different. student operators and steady state power levels were established at the 2, 20, and 200 watt During this time, the RO failed to notice that the period meter and period strip chart recorder were not workin The period meter i responds as period changes, and during steady state with no power ;
changes it normally indicates slightly less then infinity (=). On the final power increase to 2 kilowatts the inoperability of the appropriate :
period meter and period strip chart recorder was identified by the student operator when he was unable to attain a 100 second period, as observed on the period strip chart recorder, j The identification of the failed period instrumentation occurred _
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approximately 58 minutes after the reactor was started up. At that ;
point, the licensed senior reactor operator (SRO) on duty was summoned
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to the control room, arrived at the control room a few seconds later and !
immediately ordered the reactor shut-down in an orderly fashion once the I period instrumentation was confirmed to be inoperable. The reactor i period analog meter and the period strip chart recorder were found to_ be i inoperable due to a faulty test switch. The licensee discovered that i the equipment was inoperable from the time reactor startup occurred. As i a result of the faulty switch, the following technical specification's !
safety and control functions were inoperable; the 5 second period scram, !
the 15 second period rod runback, and the 30 second period rod inhibi ;
Subsequent investigation by the licensee found that the test trip switch !
associated with the period meter instrumentation had failed, leaving the
- period meter and recorder in the test (open circuit) conditio l
Contributing to the equipment failure was the failure of the R0 to completely use or review procedure SOP-103 " Reactor Startup" prior to or during the startup evolution. SOP-103, Step h., directs the operator to !
observe the period recorder for the indication that it is within its .j operating rang l
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The RO's procedure review for reactor operations was cursory and did not !
! include review of steps and precautions addressing potential instru- i mentation response changes that would be evident during approximately l four power transients. The procedures combined with the expected level !
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of operator knowledge should have been sufficient to minimize the '
duration of the inoperable reactor period instrumentation. Had the j review been more thorough, the R0 may have been more alert to specific t
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period meter and period strip chart recorder responses (at a minimum, the expected normal 100 second period indications on the chart and ,
equivalent for the meter) during the power alterations. The R0 had used ;
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linear level power strip chart indications for the power changes and i
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steady. state conditions and only confirmed the period meter indications i after the power change was completed -(the period meter and strip' chart ' ;
recorder would be correctly indicating a period slightly below the !'
infinity indication on both. meter and recorder). The RO used this information for absolute power level, but also as a means to estimate the rate of change of power level (i.e., the period).
The failure to completely follow the applicable steps is a violation of i Technical Specification 6.3 which requires the reactor staff to utilize l written procedures for the startup, merations and shutdown of the ;
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5. Human Factors Evaluation !
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Human or equipment issues contributed to the event regarding the design '
of the equipment and training. These included: :
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e The reactor and control room were designed in the mid-1960's and !
the current parameter displays and controls are not technologi- :
cally advanced. The facility has only one period strip chart !
recorder and one analog meter and they are not in close proximity !
so that an operator could simultaneously view both instruments and !
make comparisons between the display l
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e The period scram test knob control was approximately 28 years old j and had never required any repairs. The test knob (push button i design) used during the pre-start checklist to verify the 5 second s period scram, the 15 second period rod rundown, and the 30 second i rod inhibit is of the design that requires it to be pushed in
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against spring pressure and simultaneously rotated to check i various setpoint limits. The suspected "as found" condition of ,
the switch after the reactor shutdown was that it was mechanically ;
bound in the " pushed-in" position with the result that the period j meter and strip chart recorder would be inoperable indicating an ;
infinite period (a flat line on the strip chart).
The R0 cited training as a contributing factor in not promptly [
identifying inoperable reactor period instrumentation. The R0 commente 'I that no training was received on "looking for" and then "using" !
displayed information regarding changes in reactor period rather than j
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just looking for and using steady, non-changing reactor period j
information. A second area cited was that there was no specific !
training on failed period instrumentation regarding its specific failure ;
mod . Safety Sionificance !
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The safety significance was minimal. lhe safety analysis report (SAR)- ;
had analyzed several reactor startup accidents in which reactivity was j
, continually inserted by the unlikely withdrawal of three safety. rods and !
one regulating rod while the reactor was critical or subcritical. With l or without automatic protective actions (control and safety) to j
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terminate either startup. accident, the results of the analyses show that ~!
both of the accidents were self limiting due to the strong negative i reactivity feedback caused by the increase in moderator temperature and l voiding (caused by boiling). The maximum fuel clad temperature reached :
after the onset _of boiling during the power transient is 147 degrees -
Centigrade. The Technical Specifications has a limit of 580 degrees-Centigrad t Also a reactivity accident with automatic protective actions _ (control and safety) resulting in a maximum reactivity insertion of 1.5% dk/k was analyzed. In terms of comparisons the core configuration in this event i had an excess reactivity of .496% delta k/k. The results of -the- !
analyses indicate that there was no fuel clad damage and the rapid self- !
limiting shutdown mechanism was fuel and moderator thermal expansion and <
boiling. Such an accident would be terminated even with both safety channels (150% power) inoperabl !
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In all cases, no adverse consequences to the reactor, the health and safety of the public, or the reactor staff are expecte ! Corrective Actions !
i The reactor facility management has committed to implementing corrective ;
actions regarding licensed operator training and standard operating .
procedures revisions. Additional training on a monthly basis will be ;
provided to all licensed operators including an emphasis on good control !
room practices, the importance of following procedures, and the proper )
supervision of non-licensed operators at the reactor control consol .
Remedial training scheduled for the operator involved in this event 1 consists in reviewing startup and power change procedures, console ;
operations and techniques for supervising non licensed personnel at the !
reactor controls. This training will be completed prior to resumption l of licensed duties. Startup and power change procedures revisions that ;
will enhance the identification of malfunctioning reactor instrumenta- :
tion are in various management review stages. The affected dual !
function test switch has been replaced with a drawer modification ,
consisting of two single use switche l
- ' Exit Interview t
The inspectors held an exit interview on November 5, 1993, with the licensee representatives identified in Section 1 to present and discuss' :
the preliminary inspection findings. The licensee acknowledged the l information and indicated that none of the matters discussed were i proprietary in natur !
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