ML20004F213
| ML20004F213 | |
| Person / Time | |
|---|---|
| Site: | 05000077 |
| Issue date: | 06/05/1981 |
| From: | Jordan E CATHOLIC UNIV. OF AMERICA, WASHINGTON, DC |
| To: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| NUDOCS 8106160621 | |
| Download: ML20004F213 (2) | |
Text
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CATHOUC UNIVERSITY a :m5 esH
&AMEPJCA WASHINGTON D.C. 20064 m=="" x23 f A
<,s OFFICE OF THE DIRECTOR OF INFORMATION SYSTEMS AND PLANNING P
- o2 635-s2n June 5, 1981 Mr. Boyce H. Grier, Director US Nuclear Regulatory Commission Re; ion I 631 Park Avenue King of Prussia, Pennsylvania 19406
Subject:
Catholic University of America AGN-201 Reactor (License No. R-31, Docket No. 50-77), Reportable Occurrence Event of June 4, 1981
Dear Mr. Grier:
In accordance with our approved NRC technical specifications, I informed your office via telephone on June 5, 1981 of an occurrence which was observed on June 4, 1981. During the performance of a routine surveil-lance check on June 4, 1981 it was observed that the shield tank water
. te=perature automatic interlock system was set to trip at a te=perature lower than 10*C. It had apparently been in this condition since the last surveillance check perforced on January 15, 1981. During this time interval, the reactor was operated a total of 11 times. However, during this time interval, the shield tank water te=perature was never lower than 21.5'C as measured by the reactor thermometer. Therefore, the reactor was never operated in violation of any Limiting Conditions for Operation. -
The reason for the thermo-switch being in the decalibrated condition appears to be a result of a faulty calibration procedure. In the ANG-201 Reactor thermo-switch, there are two set screws. One screw serves the purpose of calibration, and the other s a locking set screw. On January 15, 1981, the trip point temperature was changed from 18.2*C to 15.5*C. After calibra-tion to this lower temperature, the calibration set screw was locked into place, and the thermo-switch placed back into its holder. It appears that in the process of locking the calibration set screw, it became decalibrated due to a small amount of rotation. This decalibration motion can be easily prevented by holding the calibration set screw as the locking set screw is turned.
Steps have been taken to prevent the recurrence of this particular probles.
The calibration procedure will be modified in two ways:
- 1. The calibration set screw will be held in place when being locked, and
- 2. The calibration will be tested again after the calibration set screw has been locked. gp Sincerely, 3
[w Q ;
i .- u ;y
. gI9616662 1 Edward D. Jordan /
Reactor Administrator cc: To attached list
Dr. Edmund D. Pellegrino President Dr. John J. Murphy Provost Mr. Steven P. Frankino University Counsel Dr. Andrew G. Favret, Acting Dean Engineering 5 Architecture i
Dr. Yun C. Whang, Chairman Mechanical Engineering Dr. David D. Ebert Reactor Supervisor 1
Mr. Warren E. Keene Radiological Safety Officer I
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