ML20133B045

Fulfills 14 Day Rept Requirements of Sections 6.5.2 & 6.6.2 of Penn State Breazeale Reactor TS for Reportable Occurrence of 961216

ML20133B045
Person / Time
Site:	Pennsylvania State University
Issue date:	12/20/1996
From:	Shirley D PENNSYLVANIA STATE UNIV., UNIVERSITY PARK, PA
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 9701020255
Download: ML20133B045 (3)

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- PENNSTATE O!!L Dasid A. Shirley The Pennsylvania State University Senior Vice President for Research 207 Old Main and Graduate Education Unisersity Park. PA 16802-1503 December 20,1996 I U. S. Nuclear Regulatory Commission Document ContmlDesk Washington,DC 20555 Re: Reportable Occurrence: Tech Spec Violation License R-2, Docket No.50-005

Dear Sir or Madame:

This letter is to fulfill the 14 day repon requirements of sections 6.5.2 and 6.6.2 of the Penn State Breazeale Reactor Technical Specifications (TS), for a mportable occurrence of December 16, ,

1996. The event was initially reponed by telephone and fax to Mr. Tom Dragoun of Region I on December 17,1996. Due to an up and coming extensive University holiday this " 14 day repon" is being filed early. An addendum will be filed on or before January 24,1997.

The reportable occurrence (section 1.1.33.b and 1.1.33.c of the TS) is that the reactor was ,

operated unknowingly in violation of a limiting condition for operation since the fuel element j temperature limiting safety system was inoperative during a pre-pulse steady state operation and  ;

during a subsequent pulse. See Tables 1 and 2a in section 3.2 of the TS. The steady state and i normal pulse peak power were both monitored and recorded as required by Tables 1 and 2a. We believe that the power limiting safety system was operative during the pre-pulse steady state operation.

A series of pulses was being performed for an experimenter who was monitoring a pulse peak l' power signal from the reactor console as an input parameter to his experiment. The peak power range of data for the first thirteen pulses was from 1148 MW to 1204 MW. The peak temperature range of data for the first thirteen pulses was from 488'C to 502*C for fuel temperature channel #1 and from 487'C to S00*C for fuel temperature channel #2. The following is a time line for events during and following the thineenth pulse (#6658) and the founeenth pulse (#6659).

l Occurrence Timeline Detail i Titng Activity g

19:41:37 Pulse # 6658 complete Peak Power = 1176 MW, Fuel Temp #1 = 4950C, Fuel Temp #2 = 4940C l h9 19:47 Stanup for Pulse # 6659 19:47:23 Fuel #1 = 13.60C Fuel #2 = 15.40C 19:48:21 Fuel #1 = 30.20C Fuel #2 = 31.90C 19:51 Reactor critical at 100 watts  !

9701020255 961220 PDR ADOCK 05000005 P ,, ,

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Page 2 December 20,1996 j i

--19:57 Pulse # 6659 initiated, Peak Power = 1168 MW, Fuel Temp #1 = 33.70C,  !

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1 Fuel Temp #2 = 32.50C 20:00 Phone call to Electronic Engineer to inquim what historical trends are most i

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j important for his trouble-shooting

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20:10 Event Evaluation Report initiated; Maintenance /Repairinitiated; Do Not Operate j Tagin place 1 20:14 Reactor Secured 1 i

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39:25 Fuel #1 = 30.20C Fuel #2 = 33.10C i i

20:40:23 Fuel #1 = 10.10C Fuel #2 = 12.40C

! As indicated above, between the last two pulses in a series of fourteen pulses, a step change occurred in both fuel temperature readouts between 19:47:23 and 19:48:21. When the fourteenth pulse was performed, the fuel temperatures remained essentially unchanged. Therefore, the reactor  ;

was operated at approximately 100 watts with an inoperative limiting safety system for several minutes and then pulsed with inoperative fuel temperature displays in violation of the TS. At the time of the step change in fuel temperatures at approximately 19:48 and again at 20:40, it is i

believed that the experimenter made a parameter change in his equipment which affected the l reactor safety system even though the experimental equipment was isolated from the fuel

temperature and power safety systems.

l Analysis of the Cause of the Occurrence  !

) A series of pulses was being performed for an experimenter who was monitoring a pulse peak

power signal from the reactor console as an input parameter to his experiment. The signal being pmvided is proportional to power in the range of 0-2000 MW. The signal comes to the point i where it is bemg monitored by way of the gamma ion chamber, peak pulse power amplifier, and

} high speed isolation board. The signal goes from the isolation board to the IO of the control and

monitoring computer. The control and monitoring computer records the data during a pulse and pmvides a pear power display for the operator, as required by the TS. The signal being provided to the experimenter was taken from between the isolation board and the control and monitoring ,

j computer. That signal went to an experimenter provided multiplexed 10 board with very high 1 input impedance. The Staff had determined that the added demand on that signal was no different

than that imposed by the control and monitoring computer. The Staff felt that the isolation was as l adequate for the experimenter as it was for the contml and monitoring computer, L Just prior to the last pulse the experimenter changed a parameter voltage on his apparatus. This

! 1arameter was also being monitoring by the experimenter's multiplexed IO board. The Staff

, xlieves that there was a failure in the multiplexed 10 board when the parameter was changed l which allowed a high frequency signal to be imposed on the line provided to the experimenter from j the reactor console. The immediate response, which was not noticed by the operator, was an

approximately 15 C step increase to appmximately 30 C in both instrumented fuel element j thermocouple indications as seen by the control and monitoring computer. When the subsequent pulse was performed the thermocouple level as seen by the contml and monitoring computer did not change as expected. Since the fuel temperature indication did not change during the pulse it is 4 likely that the limiting safety system (fuel temperature) was not operational prior to the pulse when 4

the reactor was operating at the preparatory 100 watts critical. ,

4 The Staff have been investigating various scenarios to try to duplicate the conditions and the effect while the reactor is shutdown, testing all related equipment and instrumentation, interviewing the l

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, U. S. Nuclear Regulatory Commission Page 3 December 20,1996 manufacturers of the equipment in question, interviewing the expenmenter, and pursuing other experimental avenues to increase our understanding and analysis of the occurrence. As yet the root cause or causes have not been found A vigorous pursuit of information is being made on the isolator board performance, the thermocouple safety system performance and possible avenues of extraneous signalintroduction.

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Efficacy of Cortective Action l Reactor operations are suspended. Until the above analysis has been completed corrective actions are being held in abeyance and likewise their efficacy.

Recuo.uerdations for Measures to Prevent or Reduce the Probability of Recurrence The reactor will remain secured until this event is thoroughly understood and steps taken to prevent a recurrence.

Sincerely, Dr. Rodney A. Erickson Interim Vice President for Research RAE:TLF/DEH/WFW/ldb4096.% l 1

pc: Region I Administrator T. Flinchbaugh, PSBR i

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.w' l ' m'  ;

Notarial Seal Bonnie L. Burris, Notary Public l State College Boro, Centre County '

Vy Commission Expires Nov. 22, ' 999 l

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