ML20080U580
| ML20080U580 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 10/21/1983 |
| From: | Dixon O SOUTH CAROLINA ELECTRIC & GAS CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8310260117 | |
| Download: ML20080U580 (3) | |
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SOUTH CAROLINA ELECTRIC & GAS COMPANY Post opricE 7e4 COLuualA. SOUTH CAROLINA 29218 O. W. DixoN. JR.
Vice PRESIDENT October 21, 1983 NucLEAn OPERAflONS Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555
SUBJECT:
Virgil C. Summer Nuclear Station Docket No. 50/395 Operating License No. NPF-12 Reactor Trip Initiation Criteria
Dear Mr. Denton:
A meeting was held with representatives of NRC Region II and the Office of Nuclear Reactor Regulation (NRR) on September 16, 1983, to discuss the main turbine generator load reduction event on September 12, 1983, at the Virgil C.
Summer Nuclear Station.
During this meeting, the Staff questioned why the operator did not manually initiate a reactor trip when a reactor trip window was illuminated on the First Out annunciator panel.
A clarification was requested by the Staff.
The attachment to this letter provides this information as requested.
Should you have any questions or comments, please advise.
,Very truly yours,
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0.
W.
ix ARK:OWD/dwf/fjc Attachment cc:
V. C.
Summer C. A. Price E.
C.
Roberts A.
R.
Koon E. H.
Crews, Jr.
C.
L. Ligon (NSRC)
T.
C. Nichols, Jr./O. W. Dixon, Jr.
G. J.
Braddick D. J. Roberts H.
N.
Cyrus J.
P.
O'Reilly Resident Inspector J. B.
Knotts, Jr.
Group Managers O.
S.
Bradham NPCF R.
B.
Clary File (Lic./Eng.)
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0310260117 831021 gDRADOCK 05000395 PDR L
J
6 Mr. Harold R.
Denton Reactor Trip Initiation Criteria October 21, 1983 ATTACHMENT Virgil C.
Summer Nuclear Station Reactor Trip Criteria 1.
Emergency Operating Procedure, (EOP-5), " Recovery From Reactor Trip," states that the symptom of a reactor trip is illumination of any one of the reactor trip First Out annunciators.
This is a simplification to preclude listing all reactor trips with their setpoints and trip logic which all licensed operators are required to memorize.
2.
South Carolina Electric & Gas Company's position is that irrespective of automatic reactor trip initiation, a manual reactor trip will be initiated whenever an active Technical Specification Limiting Safety System Setting, as reflected in Technical Specification 2.2-1, is reached.
This is fully understood by all licensed operators at the Virgil C.
Summer Nuclear Station.
3.
The EOP-5, as written, contains statements and steps that are short and concise by design.
Proper utilization of the EOP's requires understanding of the background for various steps and continuous training.
Paragraph 4 states the background for the symptoms of a reactor trip in EOP-5.
The operators will not be implementing EOP-5 unless these conditions in fact exist.
4.
Upon receipt of a reactor trip First Out annunciator, the operator should manually initiate a reactor trip.
Implicit in this requirement is the assumption that the plant has reached a Technical Specification Limiting Safety System Setpoint, which causes an automatic reactor trip or requires a manual reactor trip.
In the event on September 12, 1983, the problem only affected the First Out annunciator.
The entire First Out annunciator panel was in alarm with adI k
c d
Mr. Harold R.
Denton Reactor Trip Initiction Criteria October 21, 1983 Page #2 ATTACHMENT - (Continued)
"PZR PRESS HI" indicated as the first event.
Illumination of the entire panel is a condition that the operators observe daily during the annunciator testing and is not a condition observed during an actual reactor trip.
The operator knew he would receive many alarms and questioned the validity of the alarms.
He looked at the protection system bistable monitor lights which are located below and approximately three feet to the left of the First Out annunciator for verification of a reactor trip condition.
As shown on FSAR Figures 7.2-1 through 15, these monitor lights are in the circuits prior to the First Out annunciators and must be illuminated in the proper logic to cause an automatic trip and alarm.
There were no pressurizer: pressure bistable monitor lights lit, so the First Out annunciator alarm was considered invalid.
The operator also looked at the process instruments to determine actual pressurizer pressure to ensure the plant had not exceeded the Limiting Safety System Setpoint without an automatic reactor trip.
The pressure was increasing but had not reached the setpoint.
i 5.
The entire sequence described above occurred in seconds.
A review of previous trips at the Virgil C.
Summer Nuclear Station indicates that since June 16, 1983, when the requirement to initiate a manual reactor trip on all trips was implemented, the operators have been manually tripping the reactor between 4 to 20 seconds after the initiating event occurs.
The operator was interviewed and he understood when and why he should manually trip the reactor.
In this instance he would have tripped the reactor within the 4 to 20 seconds average had the plant parameters warranted it.
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