Re: Palo Verde

[Judd Sills <sillsj@GAT.COM>]

At 06:00 AM 4/1/96 -0600, you wrote:
>
>I heard a report on the radio, this morning that there are some stuck fuel 
>rods at a Palo Verde unit.  I'd appreciate it if someone knowledgable would 
>led RADSAFE know more about what's going on.   
> 
PNO-IV-96-016: DAMAGED FUEL ASSEMBLY FOUND DURING CORE DEFUELING
NRCPNO PNO1996 49616PN.TXT

                                 -1-                  March 28, 1996

PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE PNO-IV-96-016 

This preliminary notification constitutes EARLY notice of events of POSSIBLE
safety or public interest significance. The information is as initially
received without verification or evaluation, and is basically all that is
known by Region IV staff in Arlington, Texas on this date.

Facility                                    Licensee Emergency Classification
Arizona Public Service Co.                    Notification of Unusual Event
Palo Verde 2                                  Alert
Wintersburg,Arizona                           Site Area Emergency
Dockets: 50-529                               General Emergency
                                            X Not Applicable


Subject:  DAMAGED FUEL ASSEMBLY FOUND DURING CORE DEFUELING               

On March 24-25, 1996, with Palo Verde Unit 2 in a refueling outage, the 
licensee experienced difficulty in removing fuel assemblies located in the 
southeast quadrant of the core.  Adjacent Fuel Assemblies A06, A07, A08, and 
B07 could not be removed due to the refueling machine reaching the cut off 
load limit of 1600 pounds.  The licensee continued with defueling operations 
in the remainder of the core and used a video camera to observe the condition 
of the stuck assemblies. 

Using video camera, the licensee observed damage to Fuel Assembly A07. 
Specifically, the top of Assembly A07 was approximately 0.7 inch lower than
adjacent assemblies, the grid straps for Assembly A07 were lower than adjacent
assemblies, the lower end fitting for Assembly A07 was damaged, and 
approximately seven fuel rods were protruding from the bottom of the assembly.  
No damage to the fuel rods was observed, and the licensee had no indication 
of Unit 2 fuel failures prior to starting the refueling outage.  No damage to 
fuel Assemblies A06, A08, and B07 was observed.  Subsequently, the licensee 
was successful in removing Assemblies A08 and B07.  

The licensee formed task groups to develop plans for removing the last two
assemblies, to assess radiological consequences of fuel rod failure, to 
inspect the reactor upper guide structure, and to determine a root cause for 
the damage. 

The licensee observed damage to the upper guide structure in the area where 
fuel Assembly A07 was located.  The licensee has preliminarily concluded that 
the upper guide structure transmitted a load to the fuel assembly during the 
core assembly from the last outage.  The load was transmitted by the assembly 
guide tubes to the lower end fitting, resulting in damage to the end fitting 
and compression of the fuel assembly.  

On March 26 and 27, conference calls between NRR, Region IV, and the licensee
were held to discuss the licensee's plan for removing the fuel assemblies.  
The licensee stated that they believed the damaged fuel assembly is structurally
intact.  Reactor coolant chemistry is normal and there is currently no other
indication of cladding damage on Assembly A07.  The licensee indicated that 
an assembly removal procedure was developed which included the use of cameras 
to monitor the assembly and include contingency actions should fuel rods be 
observed to slip during removal.  The licensee manufactured a cover to hold 
and capture the protruding fuel rods of Assembly A07.  The licensee also 
discussed radiological consequences of fuel rod failure, actions for 
monitoring radiological conditions, and plans for protecting personnel 
involved in the removal operation.  On March 27, the licensee approved the 
use of an alternate procedure under 10 CFR 50.59 to remove Assembly A07 using 
the modified fuel handling tools.  The licensee plans to attempt to remove 
Assembly A07 on March 28, 1996.  

On March 26, NRR approved an emergency Technical Specification change to 
allow the licensee to increase the refueling machine cut off load limit for 
Assembly A06 from 1600 pounds to 2000 pounds.  The change does not apply to 
damaged Assembly A07, which is limited to 1600 pounds.  On March 27, Assembly 
A06 was successfully removed from the core without incident.

Palo Verde Unit 2 was using fuel manufactured by Combustion Engineering.  The
licensee was not going to reuse Assembly A07 for the next fuel cycle.  
Combustion Engineering has been contacted and has a fuel expert on site.  
Region IV dispatched a Branch Chief to the site on March 26, 1996, to assist 
the resident inspector followup and Unit 2 outage issues.  Additionally, two 
resident inspectors continue to monitor Units 1 and 3 which are operating at 
full power. 
 
The state of Arizona has been informed.  

Region IV received notification of this occurrence by telephone from the 
resident inspectors to the Walnut Creek Field Office at 7:30 a.m. (PST) on 
March 25, 1996.  Region IV has notified NRR, OEDO, and PAO.   This information 
herein has been discussed with the licensee and is current as of 10:30 a.m. 
(PST) on March 28, 1996.  


Contact:  D Kirsch              J. Kramer                                 
          (510)975-0290         (602)393-3638                      
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J. M. Sills, CHP                                          (619)455-2049
General Atomics, Room 01-166C      Fax:(619)455-3181
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