United States Nuclear Regulatory Commission - Protecting People and the Environment

Information Notice No. 94-13, Supplement 1: Unanticipated and Unintended Movement of Fuel Assemblies and Other Components due to Improper Operation of Refueling Equipment

UNITED STATES
NUCLEAR REGULATORY COMMISSION
OFFICE OF NUCLEAR REACTOR REGULATION
WASHINGTON, D.C.  20555

June 28, 1994


NRC INFORMATION NOTICE 94-13, SUPPLEMENT 1:  UNANTICIPATED AND UNINTENDED
                                             MOVEMENT OF FUEL ASSEMBLIES AND
                                             OTHER COMPONENTS DUE TO IMPROPER
                                             OPERATION OF REFUELING EQUIPMENT

Addressees

All holders of operating licenses or construction permits for nuclear power
reactors.

Purpose

The U.S. Nuclear Regulatory Commission (NRC) is issuing this information
notice supplement to alert addressees to an event involving unauthorized
movement of a defective spent fuel rod.  It is expected that recipients will
review the information for applicability to their facilities and consider
actions, as appropriate, to avoid similar problems.  However, suggestions
contained in this information notice are not NRC requirements; therefore, no
specific action or written response is required.

Background

The NRC issued Information Notice (IN) 94-13, "Unanticipated and Unintended
Movement of Fuel Assemblies and Other Components Due to Improper Operation of
Refueling Equipment," to alert addressees to problems that could result from
inadequate oversight of refueling operations and inadequate performance on the
part of refueling personnel.  IN 94-13 described various refueling events that
occurred at Vermont Yankee, Peach Bottom, Susquehanna, and Nine Mile Point.
These events demonstrate the importance of proper controls over, and operation
of, refueling equipment during use.  A recent event at the Waterford Steam
Electric Station (Waterford) demonstrates the potential for fuel damage or
personnel hazards which could result from fuel-handling equipment that is not
properly stored and not secured from unauthorized use.

Description of Circumstances

On February 18, 1994, the Waterford plant was operating at 100-percent power
when a senior reactor operator found an unknown object hanging from the
fuel-handling machine in the fuel-handling building.  Health physics
technicians measured radiation levels in the spent fuel pool area and found
them to be normal.  Licensee personnel remotely secured the object with vise
grips and determined that underwater radiation levels were .2 to .7 Sv/hr
[20 to 70 R/hr] at 15 centimeters [6 inches] from the object.  A Combustion
Engineering employee identified the object as a fuel rod encapsulation tube.
No visual damage was apparent on the tube.  The licensee posted a security
guard in the spent fuel pool area and reported the event to the NRC.

9406220075.                                                        IN 94-13,
Supplement 1                                                         June 28,
1994                                                         Page 2 of 3


The licensee reviewed fuel storage records and determined that the tube
contained a defective fuel rod that had been removed from an irradiated fuel
assembly several years earlier.  At that time, the tube had been placed in a
center guide tube in a grid cage stored in the spent fuel racks.  The licensee
reviewed computer access records for the fuel-handling area and interviewed
relevant personnel about the event.  Personnel who may have had access to the
fuel-handling machine completed questionnaires regarding the event.  The
licensee determined that the refueling director had used the fuel-handling
machine the day before the object was discovered and had parked the
fuel-handling machine at a location directly over the fuel rod encapsulation
tube.  However, the refueling director had not used the hoist and was not sure
that he would have noticed if the encapsulation tube was hanging from the
hoist at the time he used the machine.  Surveillance records indicated that
the fuel rod encapsulation tube must have become attached to the fuel-handling
tool sometime between February 11 and 18, 1994.

Design drawings of the cap of the fuel rod encapsulation tube showed that the
outer diameter of the cap was about equal to the inner diameter of the end of
the fuel-handling tool.  Apparently, the cap had become bound in the
fuel-handling tool when the hoist was lowered to the top of the spent fuel
rack and, when the hoist was raised, the tube was completely removed from the
grid cage.

Although contractors had performed the fuel-handling operations for previous
refueling outages, Waterford personnel were scheduled to perform the fuel
handling for the March 1994 refueling outage.  The licensee speculated that
one of the people assigned to fuel-handling activities for the March outage
may have inadvertently lifted the encapsulation tube while practicing the use
of the hoist.  Personnel were required to notify health physics staff before
accessing the refueling machine; however, health physics records showed that
no one had made such a notification during this time.  No keys or special
knowledge was needed to access the controls of the fuel-handling machine.
Electrical power could be obtained by closing two electrical breakers and
pushing one switch that were located on the machine.  The licensee questioned
several employees, but no one admitted to unauthorized use of the
fuel-handling machine.

As an interim corrective action, the licensee deenergized the computer that
controls the fuel-handling machine by opening a breaker in a locked power
control center.  The licensee planned to (1) develop a means to prevent the
fuel rod encapsulation tube from being inadvertently lifted by the
fuel-handling tool, (2) add a precaution to the operating procedure warning
operators not to lower the fuel-handling tool over the storage location, and
(3) add hoist manipulations to the lesson plans for proficiency training.

Discussion

Procedures governing the use of equipment for handling fuel and core
components may not prevent unauthorized or unintended operation of that
equipment.  Precautions such as locking out breakers that energize the
fuel-handling equipment and the placement of placards in highly visible areas
declaring that unauthorized operation of fuel-handling equipment is forbidden
.                                                        IN 94-13, Supplement
1                                                         June 28, 1994
Page 3 of 3


may help ensure that the equipment is not used without proper authorization.
Additionally, storing the fuel-handling machine in an area where accidental
movement of the hoist or grapple will not impact stored fuel or other
components may contribute to the prevention of inadvertent fuel movement or
damage.  Management attention and oversight of the operation of fuel and core
component handling equipment is important to ensure that fuel and core
components are protected from damage or unauthorized movement and that plant
personnel are protected from unnecessary exposure to radiation.

This information notice requires no specific action or written response.  If
you have any questions about the information in this notice, please contact
the technical contact listed below or the appropriate Office of Nuclear
Reactor Regulation (NRR) project manager.

/s/'d by AEChaffee


                        Brian K. Grimes, Director
                        Division of Operating Reactor Support
                        Office of Nuclear Reactor Regulation

Technical contact:  Dale A. Powers, RIV
                    (817) 860-8195

Attachment:
List of Recently Issued NRC Information Notices


Page Last Reviewed/Updated Friday, November 15, 2013