3F0784-16, Special Rept 84-03:on 840424,false Low & High Pressure Injection Occurred When Channel 2 Low Pressure Bistable Inadvertently Actuated.Cause Not Stated.Bistable Replaced. Plant Stabilized W/Injection of Borated Water Into RCS

Special Rept 84-03:on 840424,false Low & High Pressure Injection Occurred When Channel 2 Low Pressure Bistable Inadvertently Actuated.Cause Not Stated.Bistable Replaced. Plant Stabilized W/Injection of Borated Water Into RCS

ML20094N833
Person / Time
Site:	Crystal River
Issue date:	07/23/1984
From:	Westafer G FLORIDA POWER CORP.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
3F0784-16, 3F784-16, 84-03, 84-3, NUDOCS 8408160410
Download: ML20094N833 (3)

Text

-

h  %

or o* h_,Mk -

s-O QL.Go*e 1

a o00:$-[jejj RF y JUL 26 a g; 33

• e ao M

P.o, io o . .e. . o ,wr July 23,1984 3F0784-16 Mr. 3. P. O'Reilly Regional Administrator, Region II Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission 101 Marietta Street N.W., Suite 2900 Atlanta, GA 30323

Subject:

Crystal River Unit 3 Docket No. 50-302 Operating License No. DPR-72 Special Report No. 84-03

Dear Sir:

Enclosed is Special Report No. 84-03 which is submitted in accordance with Technical Specification 6.9.2.a.

Should there be any questions, please contact this office.

Sincerely, -

^

G. R. Westafer Manager, Nuclear Operations Licensing and Fuel Management AEF/feb Attachment cc: Document Control Desk U. S. Nuclear Regulatory Commission Washington, DC 20555

. .gC,Sb -

8408160410 840723 /_

PDR ADDCK 05000302 S PDR ff

/

g hh GENERAL OFFICE 3201 Thirty fourth Street South e P.O. Box 14042, St. Petersburg, Florida 33733 e 813-666 5151 l

m - -

. i

..; s- r l

l i

SPECIAL REPORT NO. 84-03 EVENT DESCRIPTION On April 24,1984 at 1040, Crystal River Unit 3 experienced a partial Engineered Safeguards System Actuation. The unit was at 97% reactor power-(865 MWe) with Surveillance Procedure, " Engineered Safeguards Monthly - Functional Test'? In progress.~ . A false low pressure and high-pressure injection occurred when, with Channel 3 tripped in order to test it, a low pressure bistable in Channel 2 inadvertently actuated completing the required two out of three, actuation logic.

-Borated water was injected into the Reactor Coolant System from the Borated Water Storage Tank. Due to quick operator action, approximately 30 gallons were injected, and the effect on the primary plant was minimal.

.With the reactor coolant pressure above setpoint, the low pressure bistable of Channel 2 was discovered in a tripped condition. The bistable was replaced. The Surveillance Procedure was satisfactorily performed.

PLANT PERFORMANCE

1. Pre-Event Crystal River Unit 3 was operating at 97% power while generating 865 MWe.

All Engineered Safeguards equipment was operable with the exception of the "B" Decay Heat Pump ' Discharge Valve which was tagged out for '

modification. Technicians were performing a Channel Functional Test of the Engineered Safeguards System.

2. Initiating Event Channel 3 of the "B" train of Engineered Safeguards was in the tripped condition due to the channel functional test. The Channel 2 Low Pressure Injection bistable failed to the tripoed condition which completed the "2 out of 3" logic to actuate the "B" train of Low Pressure Injection and High

_ Pressure Injection systems.

I

3. Post Event With the exception of the "B" Decay Heat Pump Discharge Valve (inoperable for modification), all affected Engineered Safeguards equipment actuated 4

properly. Plant operators responded quickly, evaluated the actuation as .

false, terminated the Engineered Safeguards actuation, and stabilized the plant. _

f CORRECTIVE ACTIONS I'

During an inspection of the Engineered Safeguards instrumentation following the event, technicians discovered the failure of the bistable by noting improper status -

lights on the bistable. The Low Pressure Injection bistable was replaced. The

replacement bistable was tested satisfactorily.

w e r g-+ . - .y --

e r -e d-arw*- 4-P--w- e- #m-*Fwwewe w w-' wr' t-' w-mryr- e -et--- m-.m-m =-e te e t a- =c ea--rw u -e o --- e e tem--- -er rt-re+-r----eeh * % i rstr w-wm--'-r-- ev s

The failure was not reproducible during a bench test of the failed bistable. This type of bistable uses mercury-wetted relays. Because any physical movement of these relays tends to recoat the contacts, it makes it difficult to reproduce this type of failure.

ACCUMULATED ACTUATION CYCLES Transient MUV-42 MUV-43 MUV-36 MUV-37 ES Actuation (Expected) 2 2 2 2 ES Actuation (Inadvertent) 5 5 5 5 ES Actuation (Test) 15 15 15 15 1

- m - , - - - , , - , - , - ,,,--,,--a . , - - - - , , - - , , . , - , , . - - , , , , , - -