05000250/LER-2020-003, Automatic Reactor Trip Due to High Source Range Flux During Reactor Startup
| ML20274A206 | |
| Person / Time | |
|---|---|
| Site: | Turkey Point  |
| Issue date: | 09/29/2020 |
| From: | Pearce M Florida Power & Light Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| L-2020-142 LER 2020-003-00 | |
| Download: ML20274A206 (3) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(iv)(A), System Actuation |
| 2502020003R00 - NRC Website | |
text
U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C. 20555-0001 RE: Turkey Point Unit 3 Docket No. 50-250 Reportable tvent: 2020-003-00 Date of Event: August 19, 2020 10 CFR 50.73 L-2020-142 September 29, 2020 Title: Automatic Reactor Trip due to High Source Range Flux during Reactor Startup The attached Licensee Event Report 05000250/2020-003-00 is submitted pursuant to 10 CFR 50.73 (a)(2)(iv)(A), due to actuation of the Unit 3 Reactor Protection System.
If there are any questions, please call Mr. Robert Hess at 305-246-4112 or e-mail Robert.Hess@fpl.com.
Sincerely, Michael Pearce Site Vice President - Turkey Point Nuclear Plant Florida Power & Light Company Attachments: USNRC Forms 366 and 366A, current revision cc: USNRC Senior Resident Inspector, Turkey Point Plant USNRC Regional Administrator, Region II Florida Power & Light Company 9760 SW 344th St., Homestead, FL 33035
Abstract
Turkey Point Unit 3 250 2
Automatic Reactor Trip due to High Source Range Flux during Reactor Startup 08 19 2020 2020 003 00 09 29 2020 2
000
David Stoia - Licensing Engineer (305) 246-6538
On 8/19/2020 at approximately 13:22, a plant startup on Turkey Point Unit 3 was in progress when the reactor automatically tripped while critical in Mode 2 and power increasing in the Source Range. The reactor trip signal was initiated by one of two Source Range Nuclear Power Instrumentation Channels exceeded its trip setpoint.
This event is reportable pursuant to 10 CFR 50.73 (a)(2)(iv)(A) for the initiation of the Reactor Protection System (RPS).
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- 3. LER NUMBER YEAR SEQUENTIAL NUMBER REV NO.
EVENT DESCRIPTION
On 8/19/2020, a reactor startup on Turkey Point Unit 3 was in progress following an unplanned Forced Outage. At 12:53 Unit 3 entered Mode 2 and the reactor [AC, RCT] was declared critical at 13:16. At approximately 13:22, with the reactor critical in Mode 2 and power increasing in the Source Range, the reactor automatically tripped after N-3-31, Source Range Nuclear Power Instrumentation Channel 1 [IG, JI], indicated neutron flux higher than its reactor trip setpoint of 1E05 counts per second (CPS). Unit 3 stabilized in Mode 3 at NOP/NOT conditions.
All equipment functioned as designed in response to the reactor trip.
CAUSE
The neutron flux measured by N-3-31 reached its trip setpoint of 1E05 counts per second, initiating a reactor trip signal, due to a Reactor Operator establishing too high of a startup rate during the reactor startup.
SAFETY SIGNIFICANCE
The safety significance of this event is low. All equipment functioned as designed in response to the reactor trip.
CORRECTIVE ACTIONS
Specific actions are described in Root Cause Evaluation AR 2365970.
ADDITIONAL INFORMATION
EIIS Codes are shown in the format [IEEE system identifier, component function identifier, second component function identifier (if appropriate)].
SIMILAR EVENTS
A review of reactor trip events over the previous 15 years was performed to identify potentially similar events or patterns.
No events were identified that involved automatic reactor trips caused by Source Range high flux.
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