ML20237F208
| ML20237F208 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 02/13/1996 |
| From: | Alexion T NRC (Affiliation Not Assigned) |
| To: | Boyle M NRC (Affiliation Not Assigned) |
| Shared Package | |
| ML20237F171 | List: |
| References | |
| FOIA-98-324 NUDOCS 9809020125 | |
| Download: ML20237F208 (1) | |
Text
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UNITED STATES NUCLEAR REGULATORY COMMISSION l
If WASHINGTON, D.C. 20565-0001 y
/
l February 13, 1996 NOTE T0: Michael Boyle, Technical Assistant Division of Reactor Projects I/II FROM:
om Alexion, Project Manager Project Directorate IV-1 Division of Reactor Projects III/IV DATE:
February 12, 1996
SUBJECT:
POTENTIAL NOED FOR SOUTH TEXAS 1 On January 31, 1996, the licensee informed the NRC that enforcement discretion may be requested for standby diesel generator (SDG) #11 later that evening.
Apparently, during a train A work week, SDG #11 had successfully completed its post-test run, however, during its operability surveillance, output voltage went to 4600 volts and the voltage regulator could not be controlled from the control room.
In trying to solve this problem, the licensee changed out the voltage regulator, however, they informed the PM (towards the close of business that day) that they just found out that the surveillance run was again unsuccessful (no details were available at that time).
The 72-hour LC0 would run out at 0200 CST the following morning. The PM informed the PD and the EELB branch chief of the situation. No phone calls were set up between the NRC technical staff and the licensee because the licensee did not know the cause of the problem.
On the evening of January 31, 1996, the Region faxed the PD a copy of the draft enforcement discretion (which came from the licensee), but no details of the problem nor any proposed length of time for the discretion was included because the cause of the problem was not yet known. The PD also discussed the draft with the licensee.
In addition, the PD apprised the EELB branch chief of the situation.
At 0200 CST the licensee began making preparations to start proceeding to HOT SHUTDOWN within the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />, by 0400 CST. However, the licensee replaced two failed components and declared the SDG operable at 0312 CST.
The licensee did not request enforcement discretion.
The two failed components were a repositioning board and a relay.
The board provides a predetermined signal to the voltage regulator.
The board failure resulted in a high voltage demand to the voltage regulator.
The relay isolates the output from the board to the voltage regulator when the operator wants to release the SDG from the emergency start mode to the normal mode and
)
gain manual control of the voltage regulator.
The relay failed in the closed position, resulting in a high demand to the voltage regulator with no control of the regulttor.