ML19290E814
| ML19290E814 | |
| Person / Time | |
|---|---|
| Site: | Atlantic Nuclear Power Plant  |
| Issue date: | 01/31/1980 |
| From: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | Collier A OFFSHORE POWER SYSTEMS (SUBS. OF WESTINGHOUSE ELECTRI |
| References | |
| NUDOCS 8003170069 | |
| Download: ML19290E814 (1) | |
Text
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UNITED STATES 5 %y,,3,, g,,ngg/ : E REGION 11 8
NUCLEAR REGULATORY COMMISSION o,
101 MARIETTA ST., N.W., SUITE 3100
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ATLANTA, G EORGIA 30303 JAti 31 1980 In Reply Refer To:
RII:JPO
[M' Offshore Power Systems Attn:
A. R. Collier, President P. O. Box 8000 Jacksonville, Florida 32211 Gentlemen:
This Information Notice is provided as an early notification of a possible significant matter.
It is expected that recipients will review the information for possible applicability to their facilities. No specific action or response is requested at this time.
If further NRC evaluate,as so indicate, an IE Circular or Bulletin will be issued to recommend or request specific licensee actions.
If you have questions regarding this matter, please contact the Director of the appropriate NRC Regional Office.
Sincerely, k+-
s
& James P.
eilly
/
Director
Enclosures:
1.
IE Iuformation Notice No. 80-03 2.
List of IE Information Notices Recently Issued 1
l 8003170867
s UNITED STATES SSINS No.:
6870 NUCLEAR REGULATORY COMMISSION Accession No.:
OFFICE OF INSPECTION AND ENFORCEMENT 7912190666 WASHINGTON, D.C.
20555 January 31, 1980 IE Information Notice No. 80-03 MAIN TURBINE ELECTR0 HYDRAULIC CONTROL SYSTEM Description of Circumstances:
On September t,
1979, while performing a routine startup of the Trojan Nuclear Plant, a speed control problem was encountered during warmup of the General Electric turbine and increase of turbine speed to normal operating speed (1800 RPM).
Technicians were notified and troubleshooting in accordance with the technical manual
- was commenced to resolve the apparent oscillation between the primary and backup speed control circuits which was hindering normal turbine startup operations. The technical manual indicates that it is permissible to remove either the primary or backup low value gate circuits which contain speed and acceleration error amplifiers. Upon removal of the primary low value gate circuit card, the backup card amplifiers, coming from a saturated condition, became the controlling circuit. During the shif t in control circuits (primary to backup), the speed / acceleration error signal went to maximum which resulted in a full open signal to the turbine control valves. Under existing plant conditions this appeared to the safety injection system as a major steam break downstream et the main steam isolation valves which resulted in a safety injection system actuation and reactor trip.
The Electrohydraulic Control System (EHC) technical manual indicated that slight load changes are likely when a low value gate card is removed. The effect on an unloaded turbine appears to be much more significant and tests conducted by Trojan personnel indicate that the transient is initiated whether the turbine is at a set speed or in an acceleration mode to a set speed. Discussions with General Electric personnel by the licensee have been initiated in an attempt to verify the phenomenon observed and, if applicable, alert other facilities which operate a turbine with a MK 1 EHC System regarding the potential operation of the control valves when troubleshooting the speed control unit in accordance with existing instructions.
- GEK Instruction Book 11381-D, " Speed Control Unit", Maintenance Section, Page 4.
~
IE Information Notice No. 80-03 January 31, 1980 Page 2 of 2 This information is provided as an early notification of a possible significant matter.
It is expected that recipients will review the information for possible applicability to their facilities. No specific action or response is requested at this time.
If further NRC evaluations so indicate, an IE Circular or Bulletin will be issued to recommend or request specific licensee actions.
If you have questions regarding this matter, please contact the Director of the appropriate NRC Regional Office.