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NP_Watch Jun 10, 2019
#1
The Daily Dose - Exposing the nuclear power industry while the nuclear power industry exposes you.

There are/is 1 EN(s) today, 1 associated with power stations.

[ Update to a PART21 covering multiple units ]

NRC Event Notices for June 10, 2019 |
https://www.nrc.gov/reading-rm/doc-colle...610en.html

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----------------- Power Reactor Event Notices
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----------- [ Current event for
----------- [ 2019 event history for
[ no previous ENs for this site in 2019 ]
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----------- [ Current event for
----------- [ 2019 event history for
[ no previous ENs for this site in 2019 ]
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------------[ PART 21 ] - These ENs are for issues that involve multiple site/reactor units
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20190610 | PART21 | Update PART 21 NOTIFICATION - INTROL POSITIONERS POTENTIAL LATENT DEFECT |
https://www.nrc.gov/reading-rm/doc-colle...ml#en54095

EN Revision Imported Date : 6/10/2019

EN Revision Text: PART 21 NOTIFICATION - INTROL POSITIONERS POTENTIAL LATENT DEFECT

The following is an excerpt of the Part 21 information received via email:

"Introl Positioners used by stations in G32 Terry Turbine control applicators have the potential to contain a latent defect. The defect is the result of internal corrosion which has been identified in Tl Operational Amplifiers Part No.TL084CN on the SL3EX Controller Boards of the turbine throttle valve positioner. It is believed the likely cause is associated with the ingress of solder flux into the IC Chip package on the controller board due to delamination caused by the soldering process during fabrication. The corrosion over time can result in intermittent open circuiting and high resistance in the aluminum metallization. Chlorine ionic contamination can also result in high leakage currents within the component circuitry. Failures may be manifested by a reduced valve position signal disproportional to the expected demand condition, no actuation signal (i.e. throttle valve remaining full open), or other anomalous unexpected behavior. There are three TL084CN chips on each SL3EX Controller Board within the positioner assembly. There have been two documented failures to date occurring in 2015 and 2019 in installed systems.

"Date determination was made: May 29, 2019

"Affected sites: Farley, SONGS, Cooper, Almaraz Trillo Nuclear Power Plant (Spain), Clinton, Harris, Wolf Creek, Point Beach, Hatch, Watts Bar, Sequoyah.

"Stations are advised to work directly with Curtiss-Wright SAS via the technical contacts below.

[ contact info on NRC site ]


* * * UPDATE FROM RANDY IANTORNO (CURTISS-WRIGHT) TO DONALD NORWOOD AT 1537 EDT ON 6/7/2019 * * *

The following is a synopsis of information received via E-mail:

Shearon Harris Nuclear Plant experienced an overspeed trip of the Turbine Driven Auxiliary Feedwater Pump (TDAFW)
on January 18, 2019 during routine system testing.

Upon receipt of the initial start signal, the valve remained in the fully open position causing the TDAFW to trip on overspeed.
Investigation into the overspeed trip revealed the positioner was not controlling the actuator properly in response to the governor command signal.
 This situation and subsequent troubleshooting led to replacement with the site spare positioner.
Once installed, the system responded as expected and the suspect positioner was sent to Curtiss-Wright SAS (CW SAS) for evaluation.

In a joint effort between CW SAS and Paragon Energy Solutions (PES),
the positioner was tested and evaluated to determine the cause of the failure.

Corrective action which has been, is being, or will be taken:
- The three TI chips on the affected board have been successfully replaced at PES.

The repaired positioner will be configured and returned to Shearon Harris.

- The evaluation of suspect chips has been limited to those removed from the failed positioner,
along with some supplied to PES by CW SAS. Work is ongoing in this area.

- A complete list of potentially affected installations is listed in the PES Part 21 Report dated May 31, 2019.

- Although this defect has the potential of preventing the Electronic Governor Speed Control System (EGSCS) from performing its intended safety function, it does not prevent the Terry Steam Turbine from operating.

If the EGSCS fails, the turbine can be operated manually using the Trip and Throttle Valve (TTV)
to control speed by regulating steam flow to the turbine.
- Steps are being taken to develop a plan to replace chips on affected positioner boards.

This is still in the preliminary stages and specific recommendations will follow.

Notified R1DO (Carfang), R2DO (Rose), R3DO (Kozak), R4DO (Kellar), Part 21 Reactors E-mail group, and Part 21 Materials E-mail group.
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------------Other reactor info from daily power tracking https://www.nrc.gov/reading-rm/doc-colle...atus/2019/
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[  ]


Region 1

PA_Beaver_Valley_1 @ 100 % unch from 100 % Sunday; 81 % Saturday
[ no EN, unk reason for power drop. ]

PA_Limerick_2 @ 100 % unch from 100 % Sunday; 21 % Saturday
 MANUAL SCRAM DURING RAPID PLANT SHUTDOWN |
 https://www.nrc.gov/reading-rm/doc-colle...ml#en54098

MA_Pilgrim_1 @ 0 % - PERMANENT SHUTDOWN

NJ_Salem_1 @ 0 % [ RPV OPEN ( 56 / 28 ) ] RFO started early


Region 2

AL_Browns_Ferry_2 @ 95 % unch from 95 % Sunday; 95 % Saturday
[ Completed RFO ( 39 / 25 ) ] power uprate testing, missed planned restart date

NC_Brunswick_1 @ 100 % unch from 100 % Sunday; 79 % Saturday
[ no EN, unk reason for power drop. ]

GA_Hatch_1 @ 100 % up from 82 % Sunday; 100 % Saturday
[ no EN, unk reason for power drop. ]

FL_Saint_Lucie_1 @ 0 % since 20190425
 AUTOMATIC REACTOR TRIP DUE TO TURBINE GENERATOR TRIP |
 https://www.nrc.gov/reading-rm/doc-colle...ml#en54027


Region 3  

IL_Clinton_1 @ 98 % unch from 98 % since 20190527
[ 98-99 % are this units normal thermal power range. ]

MI_Fermi_2 @ 100 % unch from 100 % Sunday; 72 % Saturday
[ no EN, unk reason for power drop. ]

IL_La_Salle_1 @ 100 % up from 80 % Sunday; 100 % Saturday
[ no EN, unk reason for power drop. ]


Region 4

AR_Arkansas_2 @ 0 % unch from 0 % since 20190527
 AUTOMATIC REACTOR TRIP DUE TO A REACTOR COOLANT PUMP TRIP ON GROUND FAULT |
 https://www.nrc.gov/reading-rm/doc-colle...ml#en54091

WA_Columbia_2 @ 0 % [ RPV OPEN ( 28 / 31 ) ] plnd start 20190515 ] started early  

LA_RiverBend_1 @ 38 % unch from 38 % Sunday; 32 % Saturday
 MANUAL REACTOR SCRAM DUE TO LOW REACTOR WATER LEVEL |
 https://www.nrc.gov/reading-rm/doc-colle...ml#en54096
[ Exit RFO ( 42 / 34 ] 2nd restart failed; 1st restart failed; missed planned restart date

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[ There is/are currently 02 unit(s) with the RPV OPEN - ref the 2019 Spring Refueling Outage Schedule and Status ]

posted by Staup Knewkinus a Dane Gerous production. All human rights reserved.
 
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