Letter Sequence Request |
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MONTHYEARML20074A7561983-04-27027 April 1983
Clarifies Proposed Changes in Undervoltage Protection & Reiterates Schedule for Implementation of Design Changes & Mods.Existing non-Class IE Undervoltage Relays Will Be Retained as Protection for 4,160-volt Buses
Project stage: Request
ML20212N6621985-08-31031 August 1985
Technical Evaluation Rept for Proposed Change to Operation of Ginna Fuel Pool Charcoal Filter Sys, Informal Rept
Project stage: Request
ML20135H5631985-08-31031 August 1985
Truth-Analysis/Action-Reaction Review of 480-Volt Essential Bus Tie Breaker Control Scheme, Final Rept
Project stage: Other
ML20135H5591985-09-13013 September 1985
Forwards Truth-Analysis/Action-Reaction Review of 480-Volt Essential Bus Tie Breaker Control Scheme, Final Rept & Provides Evaluation of Control Logic Design
Project stage: Other
IR 05000267/19850171985-09-13013 September 1985
Insp Rept 50-267/85-17 on 850617-0816.Violation Noted: Failure to Rept Nine Circulator Trips in 1984 & Seven Trips in 1985 & No Differential Helium Pressure Maintained When Pcrv Pressure Above 100 Psia
Project stage: Request
ML20137S3631985-09-13013 September 1985
Corrected Page 1 to Responding to 850614 Commitment to Perform Evaluation of Emergency Diesel Generator Control Logic Circuitry.Ltr Number Changed
Project stage: Other
ML20134A3651985-10-23023 October 1985
Amends Correction Portion of Item 2 (286G1A & 286G1B) in Util Re Results of Proto-Power Corp Analysis Concerning Emergency Electrical Power Sys Independence
Project stage: Other
ML20137B3561986-01-0303 January 1986
Informs That Design Changes Involving Emergency Diesel Generator (EDG) Control Logic Circuitry Implemented.No Single Failure Will Interfere W/Proper Operation of Redundant EDG
Project stage: Other
ML20137K9991986-01-14014 January 1986
Notifies That Design Changes in Emergency Diesel Generator Control Logic Circuitry Implemented,Per 850913 Commitment. Changes Assure That Failure Will Not Interfere W/Operation of Redundant Generator.Ltr Supersedes
Project stage: Other
ML20140H1101986-03-31031 March 1986
Submits Info Re Startup Check List for Automatic Operation of Emergency Diesel Generators,Sys Operating Procedure 92-04,in Response to NRC .Numbers Will Be Assigned to All Valves in Emergency Diesel Generator Rooms
Project stage: Other
ML17251A7911986-03-31031 March 1986
Reactor Containment Bldg Integrated Leakage Rate Test
Project stage: Request
ML20206T7341986-07-0101 July 1986
Submits Summary & Schedule of Mods to Be Performed on Emergency Diesel Generator Control Circuitry in Response to 860515 & 21 Telcons.Mods Will Be Completed Prior to Startup from Current Equipment Qualification Outage
Project stage: Other
ML20213G5811986-08-0707 August 1986
Draft Review of Fort St Vrain Onsite AC Standby Power Sys W/Regards to Compliance to Single Failure Criterion & Ser
Project stage: Draft Other
05000267/LER-1986-022, :on 860715,failure Point in 480-volt Ac Essential Bus 1 & 2 Undervoltage Relay Logic Identified. Caused by Misunderstanding of Basic Design Requirements. Designer & Independent Reviewer Reprimanded1986-08-14014 August 1986
- on 860715,failure Point in 480-volt Ac Essential Bus 1 & 2 Undervoltage Relay Logic Identified. Caused by Misunderstanding of Basic Design Requirements. Designer & Independent Reviewer Reprimanded
Project stage: Other
ML20213G5641986-11-12012 November 1986
Forwards Onsite Class 1E Power Sys Design Features Review Status Rept Based on FSAR & NRC 860814 Meeting W/Licensee & Inel Draft Review of Fort St Vrain Onsite AC Standby Power.... Resolution to Problems Requested Before Restart
ML20212D8641986-12-24024 December 1986
Summary of 861209 Meeting W/Util Re Plant Emergency Electrical Power Sys.Fsar Commitment Re Emergency Diesel Generators revised.Marked-up Draft Rept Re Ac Standby Power Sys Encl
ML20212G8671987-01-0909 January 1987
Forwards Rev a to EE-92-0008, Engineering Evaluation of Load Shedding,Load Auto Start Prohibit,Load Sequencing,Bus Tie Breaker Alignment & Generator Breaker Closing Portions of Emergency Diesel Generator Control Circuitry
Project stage: Other
ML20207R9471987-03-0606 March 1987
Rev 1 to Review of Fort St Vrain Onsite AC `Standby Power Sys Re Compliance to Single Failure Criterion & Ser
Project stage: Other
ML20207R9381987-03-0606 March 1987
Forwards Rev 1 to EGG-NTA-7456, Review of Fort St Vrain Onsite AC `Standby Power Sys Re Compliance to Single Failure Criterion & Ser
Project stage: Approval
ML20207S6271987-03-12012 March 1987
Summary of 870210 Meeting W/Util Re Emergency Diesel Generator Electrical Independence.List of Attendees Encl
Project stage: Meeting
1986-12-24
[Table View] |
Text
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Public Service Comixmy cf Cinh 2420 W. 26th Avenue, Suite 1000 Denver, Colorado 80211
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April 27, 1983 Fort St. Vrain Unit No. 1 P-83161 Mr. John T. Collins, Regional Administrator
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Region IV i
U. S. Nuclear Regulatory Commission s
611 Ryan Plaza Drive MAY - 6 8 Suite 1000 Arlington, Texas 76011
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SUBJECT:
Electric Power Systems
REFERENCES:
G-83138 from Madsen to Lee dtd 3/30/83; G-82338 from Clark to Lee dtd 10/12/82
Dear Mr. Collins:
The intent of this letter is (1) to clarify certain information pertaining to the proposed changes in Fort St.
Vrain's undervol tage protection and, (2) to reiterate our schedule for implementation of design changes and modifications previously outlined.
At present the undervoltage protection at Fort St. Vrain utilizes two non-class 1E relays which monitor the 4160V output of the Reserve Auxiliary Transformer.
In the event that one or both of these relays should actuate or fail, certain class IE functions will be initiated, i.e.
diesel generator starting, 480 volt bus breaker tripping and load shedding on the 480 volt class IE buses.
It is our intent that no class 1E functions be initiated by these non-class 1E relays.
For this reason, these safety functions have been assigned to the proposed class IE protective relay system to be installed on the 480 volt class 1E buses.
The existing non-class 1E undervoltage relays will be retained as protection for the 4160 volt non-class 1E buses.
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8305160048 830427 h
PDR ADOCK 05000267 P
PDR
P-83161 Page 2
,a As indicated in previous correspondence P-82399 (Warembourg to Kuzmycz dated 9/16/82) we have requested deferring submittal of a finalized Technical Specification concerning the proposed undervoltage relaying modifications until those modifications are undertaken.
As stated in letter P-82169 (Brey to Kuzmycz dated 5/28/82) we feel that the most expedient method of executing design changes and modifications relating to the proposed degraded grid voltage protection would be to implement these changes concurrent with the upgrading and change out of the 480 volt class 1E essential buses. The replacement of the 480 volt class 1E buses is an operational decision made by Public Service Company of Colorado and is not an NRC connitment.
The change out of the 480 volt class 1E buses will coincide with the 3rd refueling outage at Fort St. Vrain presently scheduled for late 1983.
If you have any questions concerning this matter do not nesitate to call.
Very truly yours, 9
p mhhW CA H. L. Brey, Manager Nuclear Engineering Division HLB /bs:pa
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