ML042990195

Cause Analysis CR 03-00049

ML042990195
Person / Time
Site:	Davis Besse
Issue date:	10/15/2004
From:	- No Known Affiliation
To:	Office of Nuclear Reactor Regulation
References
FOIA/PA-2003-0224 CR 03-00049
Download: ML042990195 (1)

Text

CAUSE ANALYSIS lCR Number NOP-LP-2001-03 03-00049 Category I Eval Code: CA Condition Description and Cause Basis: If Yes, select one

-1 Hardware I Degraded Condition Resolution Required? [ Yes No E Repair El Scrap E Rework El Use-As-Is Condition

Description:

Bump started RCP 1-2. Received annunciator 8-2-B, RCP 1-2 Motor Trouble/Trip. RCP 1-2 tripped Instantaneously. Field report indicates the trip occurred on relay 87, Motor Differential.

Discussion:

Prior to this event, RCP 1-2 tripped the day before. Refer to CR 03-00042. Corrective action for that event required two phases of T - Leads to be swapped. The direction given by the Electrical Supervisor was that phase A and C should be swapped.

The electrician assigned the task of performing this action, believed that phase C cable would exceed the minimum bend radius and swapped phase A and B instead. The configuration of Current Transformers feeding was changed to reflect this change.

Following this event, a Troubleshooting plan was developed to determine the cause of the trip and included the following:

a) Remove breaker HB03 from Its cubicle and perform an Inspection of the breaker.

b) Verify that breaker HB03 50/51A and 50151 C relays (P9-11382 and P9-11382) have the proper set point.

c) De-terminate 2 or 3 T-leads at the motor terminal box to confirm proper T-lead labeling.

d) Install the test fixture and ground one T-lead at a time at the test fixture and determine which lead at the motor indicates grounded. Repeat I or 2 times to Identify LI, L2, and L3 at the motor.

e) Label leads appropriately.

f) Terminate T-leads exactly as they were de-terminated.

g) At the motor terminal box perform the following (refer to DWG E-0052B SH 46A and Westinghouse drawing 3800C61):

- Verify CTI corresponds to station LI

- Verify CT2 corresponds to station L2

- Verify CT3 corresponds to station L3

- Verify Di connected to + of CT1

- Verify D2 connected to + of CT2

- Verify D3 connected to + of CT3

- Verify DII connected to - of CTI

- Verify D12 connected to - of CT2

- Verify D13 connected to - of CT3 h) Lift leads D12 and D13 at the motor terminal box. Verify continuity between positions 8 and 9 of 87M at HB03.

i) Land lead D12 and lift lead DiI at the motor terminal box. Verify continuity between positions 14 and 15 of 87M at HB03.

j) Land lead Dl 3 and lift lead D12 at the motor terminal box. Verify continuity between positions 18 and 19 of 87M at HBO3.

k) Land leads DII and D12 at the motor terminal box.

I) Perform DB-PF-05064 de-energized motor tests of MP36-2 using the test fixture install In HBO3.

m) Remove the test fixture from HB03 and Install breaker HBO3.

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