ML19260D229
| ML19260D229 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 01/31/1980 |
| From: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | Mattimoe J SACRAMENTO MUNICIPAL UTILITY DISTRICT |
| References | |
| NUDOCS 8002080146 | |
| Download: ML19260D229 (1) | |
Text
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SUITE 202, WALNUT CREEK PLAZA
- ,,,e WALNUT CRE E K, CALIFORNIA 94596 January 31, 1980 Docket No. 50-312 Sacramento Municipal Utility District P. O. Box 15830 Sacramento, California 95813 Attention: Mr. John J. Mattimoe Assistant General Manager Gentlemen:
This Information Notice is provided as an early notification of a pcssibly 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 flRC 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.
Sincerely, f
Sv.,c LS-R. H. Engelken Director
Enclosures:
1.
IE Information Notice No. 80-03 2.
List of IE Information Notices Recently Issued cc w/ enclosures:
R. J. Rodriguez, SMUD L. G. Schwieger, SMUD 1943 152 8002080}q 4
UflITED STATES SSINS No.: 6870 NUCLEAR REGULATORY C0ffilSSION Accession fio.:
0FFICE OF INSPECTION AND Ef1FORCEfiEflT 7912190666 WASHIIlGTON, D.C.
20555 January 31, 1980 IE Infornation Notice No. 80-03
'1AIN TURBINE ELECTR0 HYDRAULIC CONTROL SYSTEM Description of Circunstances:
On September 6,1979, while cerforming a routine startup of the Trojan Nuclear Plant, a speed control problen, was encountered during warnup of the General Electric turbine and increase of turbine speed to normal operating speed (1800 RPM). Technicians were notified and trouble shooting in accordance with the technical nanual was comenced to resolve the apparent oscillation between the primary and backuo speed control circuits which was hindering nomal turbine startup operations, The technical manual indicates that it is pernissible to renove 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 shift in control circuits (primary to backup), the speed / acceleration error signal went to maximun which resulted in a full open signal to the turbine control valves.
Under existing plant conditions this appeared to the safety injection systen as a major steam break downstream of 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 tn01ne appears to be nuch nore significant and tests conducted by
- GEK Instruction Book 11381-0, " Speed Control Unit", flaintenance Section, Page 4.
1943 153
IE Information f'otice No. 80-03 January 31, 1980 Page 2 of 2 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 attenot to verify the phenomenon observed and, if applicable, alert other facilities which operate a turbine with a f1K 1 EHC Systen regarding the potential operation of the control valves when trouble shooting the speed control unit in accordance with existing instructions.
This information is provided as an early notification of a possible significant matter.
It is expected that recipients will review the information for oossible applicability to their facilities, flo specific action or response is requested at this tine.
If further NRC evaluations so indicate, an IE Circular or Bulletin will be issued to recontend or request specific licensee actions.
If you have questions regarding this matter, please contact the Director of the appropriate NRC Regional Office.
Enclosure:
List of Recently Issued IE Information flotices 1943 154
IE Infornation Notice No. 80-03 Enclosure January 31, 1980 RECEllTLY ISSUED IE INFORMATION NOTICES Infornation Subject Date Issued To Notice f:o.
Issued 80-02 8X8R Uater Rod Lower 1/25/80 All EWR Facilities End Plug Wear holder power reactor OLs or cps 80-01 Fuel Handling Events 1/4/80 All holders of power reactor OLs and cps 79-37 Cracking in Low Pressure 12/28/79 All power reactor OLs Turbine Discs and cps 79-36 Computer Code Defect in 12/31/79 All power reactor OLs Stress Analysis of Piping and cps Elbow 79-35 Control of f*aintenance 12/31/79 All power reactor facilities and Essential Equipment with an OL or CP 79-34 Inadequate Design of 12/27/79 All holders of power reactor Safety-Related Heat OLs and cps Exchangers 79-33 Imoroper Closure of 12/21/79 All power reactor facilities Prinary Containnent holding OLs and cps Access Hatches 79-32 Separation of Electrical 12/21/79 All power reactor facilities Cables for HPCI and ADS holding OLs and cps 79-31 Use of Incorrect Anolified 12/13/79 All holders of power reactor Response Spectra (ARS)
OLs and cps 79-30 Reporting of Defects and 12/6/79 All power reactor facilities Noncompliance,10 CFR Part 21.
holding OLs and cps and vendors inspected by LCVIP 79-29 Loss of flonSafety-Related 11/16/79 All power reactor facilities Reactor Coolant System holding OLs or cps Instrurentation During Opera tion i943 155