United States Nuclear Regulatory Commission - Protecting People and the Environment

12/10/1998


U.S. Nuclear Regulatory Commission Operations Center Event Report

Page 1

Other Nuclear Material Event# 35129
Rep Org: FISHER-ROSEMOUNT Notification Date / Time: 12/09/1998 12:17 (EST)
Licensee: FISHER-ROSEMOUNT Event Date / Time: 12/09/1998 11:17 (CST)
Region: 3 Last Modification: 12/09/1998
Docket #:
City: Eden Prairie Agreement State: No
County: License #
State: MN Notifications: MARK RING R3
NRC Notified by: JERRY HANSON VERN HODGE NRR
HQ Ops Officer: JOHN MacKINNON JOHN ROGGE R1
Emergency Class: NON EMERGENCY DAVID GRAVES R4
10 CFR Section: CHARLES OGLE R2
21.21 UNSPECIFIED PARAGRAPH
10 CFR PART 21 REPORT REGARDING ROSEMOUNT MODEL 710 TRIP UNITS

Rosemount Nuclear Instrumentation, Inc. (RNII) has determined that they have a potential deviation related to certain 710DU0TS 4-20 mA master trip units. A jumper wire (J1) may be incorrectly installed on the circuit card assembly (CCA) of the master trip units. This jumper should only be installed on the CCA's of Mode 710DU0TS slave trip units. This jumper bypasses a buffer circuit that serves to protect the 1-5 volt bus of the master trip unit from electrical faults on a slave unit(s). This circuit configuration places the master trip unit in an unqualified (untested) condition and may expose the master trip unit to an unanalyzed failure mode.

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