ML19320D482
| ML19320D482 | |
| Person / Time | |
|---|---|
| Site: | Atlantic Nuclear Power Plant  |
| Issue date: | 05/28/1980 |
| From: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | Collier A OFFSHORE POWER SYSTEMS (SUBS. OF WESTINGHOUSE ELECTRI |
| References | |
| NUDOCS 8007210414 | |
| Download: ML19320D482 (1) | |
Text
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q'o UNITED STATES f
NUCLEAR REGULATORY COMMISSION o
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[a i REGION 11 8
o 101 MARIETTA ST N.W., SUITE 3100 P4 ATLANTA, GEORGIA 20303 o
In Reply Refer To:
MAY 281980 THis 00curiENT CONTAINS RII:
POOR QUAllTY PAGES 1
437 Offshore Power Systems Attn:
A. R. Collier, President P. O. Box 8000 Jacksonville, Florida 32211 Gentlemen:
The enclosed Circular No. 80-13, is forwarded to you for ir. formation.
If there are any questions related to your understanding of the suggested actions, please contact this office.
Sincerely,
-- p _ f
< M % v-James P. O'Reilly Director
Enclosures:
1.
IE Circular No. 80-13 2.
List of Recently Issued IE Circulars t
8007210] lL4
. 4-i s
SSINS No.: 6830 Accessions No.:
UNITED STATES 7910250495 NUCLEAR. REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C. 20555 o
t May 28, 1980 1
IE Circular No. 80-13 GRID STRAP DAMAGE IN WESTINGHOUSE FUEL ASSEMBLIES Description of Circumstances:
During t's refueling operation at Salem Unit 1, it was noted by the licensee that son-
'f e assemblies that were removed had suffered grid strap mechanical damage.
norted to the NRC in LER 79-44. Subsequent to this r
discovery
...emblies were removed from the core for examination.
f The degret
- mamage to'the grid straps was classified in three cate; gories: small pieces missing (15 assemblies), grid material ripped and iold over (5 assemblies), larger sections missing and fuel pins exposed (11 assemb-lies). No damage to the fuel pins was observed. A total of 31 assemblies suffered some grid damage.
The damage appeared to be the result of corner to corner interaction of the grid straps of diagonally adjacent fuel assemblies during the vertical loading and unloading movements. No correlation of the damage to core location, grid strap elevation, or manufacturing and shipping batches has been identified.
The licensee and the fuel manufacturer established the following guidelines for reloading damaged assemblies: (1) those assemblies with full width pieces missing will not be reloaded for cycle 2, (2) those assemblies with deformed edges and those with small pieces missing will be reloaded with special pro-cedures to prevent further damage.
Salem Unit 1 is fueled with 17X17 Westinghouse assemblies. Similar grid problems have occurred at other facilities fueled with 14X14 and 15X15 Westinghouse assemblies; however, fewer assemblies were damaged in those instances.
Recommended Actions:
All licensees using 14X14, 15X15, or 17X17 Westinghouse assemblies are advised to:
(1) Visually inspect grid straps of those fuel assemblies which are discharged from the core as well as those assemblies which are moved to the spent fuel pool for control rod replacement and are subsequently returned to the core.
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IE Circular No. 80-13 May 28, 1980 i
Page 2 of 2 (2) Review the fuel handling precautions recommended by Wertinghouse at a meeting on May 25, 1979, with NRC and the licensee for Salem (Attachment 1). Adopt those recommendations which are pertinent.
No written response to this Circular is required.
If you require additional information regarding these matters, contact the Director of the appropriate NRC Regional Office.
Attachment:
Summary of Meeting Notice dated 5/30/79
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LICENSEE: PUBLIC SERVICE ELECTRIC & GAS COMPANY (PSE&G) i g q),,e
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FACILITY: SALEM UNIT 110. 1 l
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SUBJECT:
SLHiARY OF NEETING HELD ON MAY 25. 1979. TO DISCUSS
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DAMAGE OBSERVED TO FUEL GRID ASSEMBLIES DURING TE OfD W W d!A F SALEM UNIT 110.1 REFUELING OUTAGE'
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On May 25, 1979, we met with representatives of Public Service Electric &
i Gas Company (PSE&G) and Westinghouse to discuss the cause and extent of dasage observed to the Salem Unit No.1 fuel grid assemb, lies during the current refueling outage for cycle 2.
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The licensee and Westinghouse provided a detailed discussion of the
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' damage observed to the Salem fuel grid assemblies during the cycle 2 MMN ;.N't*!
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' refueling outage which comenced in April 1979.
Due to the indications i
. observed during the initial stages of the outage, the decision was made to unload all fuel assemblies from the core.
Of the fuel assemblies (193) inspected, 28 asse:nblies were detemined to have varying degrees ;..
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of dar. age to one or more of the eight grid assemblies per fuel assembly.
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The grid assemblies provide lateral support to the fuel rods.
In no case was damage observed to the fuel rods themselves. The grid assembly damage observed, which we.s generally located at the corners of the grid i
asse:iblies, was categori.:ed a; follows:
Categor.y T.ype of__ Damage No. of Grid AssembliesMh 1
saali pieces missing 15 2
grid material ripped 4
and laid over NN S
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larger sections missing and fuel pins exposed
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for cycle 21 as a pmcautionary measure assemblies with category 3 damage will not be reloaded. The basis for this determination was that assemblies ~
with category 1 and 2 damage can be used witho'ut any loss of function of u.am =_ e <a..
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longer fully restrain all fuel mds in the manner provided for in the j
, design. Their reuse should be based on further analysis.
Of the data collected and the reload films reviewed, no pattern has been
'. established for the observed dantge. Also, it has not been determined whether the damage occurred during fuel insertion for cycle 1, or during removal or readjustments for cycle 2, or both.
It is believed that corser-tre corner interaction may have occurred between grid assemblies of adjacent fuel assem611es especially when diagonal fuel assemblies have
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been removed and some degree of lateral movement is possible.
Under these conditions the grid assemblies may have been aligned such that the corners interacted during vertical movement.
Of the pieces missing (about 61), a total area d about 25fn2 is involved.
These pieces range frem about.3fnZ up to about 5.5fn2 Approximately 1
.12in2 ef anterial has been recovered fronithe core or the fuel assemblies during the unloading of the core.
In addition. the core was inspected with a TV camera. With regard to the potential for flow blockage from the missing material, Westinghouse indicated that if all the peices originally missing were to be located such as to partially block the inlet nozzle area of the one fuel assembl, analyses similar to that described in Section 3.4 of the Salem FSAR indicate that no problem would exist. The i
smaller pieces still missing ere expected to easily pass up through the fuel assemblies during operation and not present any problems to the control rod drive mechanisms.
The largest that any of the missing pieces could be than 2inI. based on the base areas on grid assemblies, is slightly greater 4
Westinghouse has reconnended additienal fuel assembly handling precautions 3
to minimize the potential for corner-to-corner interaction between grid assemblies.
Included among these reconnendations are,1) a revised loading sequence which would load fuel assemblies from the sides of the core toward the center, 2) a slight offset in position as corner fuel i
assemblies are lowered into the core until they are about 10" above the base plate and then making a lateral adjustment into final position,
- 3) the conditionally accepted assemblies in categories 1 and 2 would be loaded is a special sequence to minimize relative motion with adjacent i
assemblies. 4) those assemblies in category 2 would be loaded against the core baffle, where possible and 5) revised load cell limits on the mani-pulator crane in an attempt to more easily detect increased loads during fuel handling.
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Westinghsise"dnowfedged and sumarized similar grid'assedly 'probisms~~~
.cQ~, did not involve as mary fuel assemblies as in this Salem situation.
that have occurred at other facilities. Although these other occurrences 7
'similar damage has been observed to 14x14,1Sx15 and 17x17 fuel assemblies.
In some instances the fuel was removed, and in others, the fuel was re-loaded w'n no known adverse effects.
With regard to the Salem Unit I refueling analysis, the licensee indicated Preliminar11y, that the core parameters are expected to be essentially unchanged due to the revised core loading that will realt.
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.,,:sThe licensee agreed to address the potential effects that ;;he unaccounted for pieces of grid material might have on the core thermal hydraulic analysis and on control rod operation.
This infonnation will be included prior to restart of Selen 1 in a supplement to the licensee's reload application for c/cle 2.
. b Gary G.
h Project Manager Operating Reactors Branch il Division of Operating Reactors
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Enclosure:
List of Attendees cc: w/ enclosure i
See next page T
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IE Circular No. 80-13 Enclosure i
. May 28, 1980 RECENTLY ISSUED IE CIRCULARS Circular Subject Date of Issued to No.
Issue 80-13 Grid Strap Damage in 5/28'80 All holders of Reactor Westinghouse Fuel Assemblies OL and Construction Permits for PWRs 80-12 Valve-Shaft-To-Actuator Key 5/14/80 All holders of Reactor May Fall Out of Place When '
OLs and cps Mounted Below Horizontal Axis 80-11
_ Emergency Diesel Generator 5/13/80 All holders of a power Lube Oil Cooler Failures reactor OL or CP 80-10 Failure to Maintain 4/29/80 All holders of Reactor Environmental Qualification OLs and cps of Equipment 80-09 Problems With Plant Internal 4/28/80 All holders of a power Communications Systems reactor OL or CP 80-08 BWR Technical Specification 4/18/80 All General Electric Inconsistency - RPS Response BWR's holding a power Time reactor OL 80-07 Problems with HPCI Turbine 4/3/80 All holders of a power Oil System reactor OL or CP 80-06 Control and Accountability 4/14/80 Medical licensees in Systems for Implant Therapy Categories G and G1 Sources 80-05 Emergency Diesel-Generator 4/1/80 All nolders of a power 4
Lubricating Oil Addition and reactor OL or CP Onsite Supply 80-04; Securing of Threaded Locking 3/14/80 All holders of a power Devices on Safety-Related reactor OL or CP Equipment 8C-03 Protecti n from Toxic Gas 3/6/80 All holders of a Hazards power reactor OL 80-02 Nuclear Power Plant Staff 2/1/80 All holders of Reactor Work Hours OLs, including research and test reactors, and cps h
ust.
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