ML18082A592
| ML18082A592 | |
| Person / Time | |
|---|---|
| Site: | Salem  |
| Issue date: | 05/28/1980 |
| From: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | Schneider F Public Service Enterprise Group |
| References | |
| NUDOCS 8006200029 | |
| Download: ML18082A592 (7) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION REGION I 631 PARK AVENUE KING OF PRUSSIA, PENNSYLVANIA 19406 Docket No. 50-272 50-311 Public Service Electric and Gas Company ATTN:
Mr. F. W. Schneider
- Vice President - Production
- 80 Park Place Newark, New Jersey 07101 Gentlemen:
/ May 28, 1980
- The. enclosed IE Circular No. 80-13, 11Grid Strap Damage in Westinghouse Fuel Assemblies;* is forwarded to you for information.
No written response is required. If you desire additional information regarding this matter, please contact this office.
Sincerely,
Enclosures:
- 1.
IE Circular No. 80-13 with Attachment 2-List of Recently Issued IE Circulars CONTACT:
D. L. Caphton (215-337-5262) cc w/encls:
F. P. Librizzi, General Manager - Electric Production E. N. Schwalje, Manager - Quality Assurance R. L. Mittl, General Manager - Licensing and Environment H. J. Midura, Manager - Salem Generating Station Q
I _,.
- ENCLOSURE" 1 UNITED STATES
. SSINS No. : 6830 Accessions No.:
7910250495 NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C. 20555 GRID* STRAP DAMAGE IN WESTINGHOUSE FUEL ASSEMBLIES Description of Circumstances:
IE Circular.No. 80-13 Date:
May 28, 1980 Page 1 of 2 During the refueling operation at Salem Unit 1, it was noted by the licensee that some of the assemblies that were removed had suffered grid strap mechanical damage.
This was reported to the NRC in LER 79-44.
Subsequent to this discovery all fuel assemblies were removed from the core for examination.
The degree of the damage to the grid straps was classified in three categories: small pieces missihg (15 assemblies), grid material ripped ~nd laid over (5 assemblies),
larger sections missing and fuel pins exposed (l~ assemblies).
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 fo.r 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 furthe.r.damage.
Salem Unit 1 is fueled with 17Xl7 Westinghouse assemblies.
Similar grid problems have occurred at other facilities fueled with 14-Xl4 and 15Xl5 Westing-house assemblies; however, fewer assemblies were damaged in those instances.
Recommended Actions:
All licensees using 14Xl4, 15Xl5, or 17X17 Westinghouse assemb 1 i es 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.
~
I Enclosure l*
.. Circular No. 80-13 Date:
May 28, 1980 Page 2 of 2 (2) Review the fuel handling precautions recommended by Westinghouse at a
- meeting oi1 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 required additional information regarding these matters, contact the Director of the appropriate NRC Regional Office.
Attachm.ent:
Summary of Meeting Notice
. dated 5/30/79
I Attachment to IE Circ:1r... N~. 80-13 UNITED STATES NUCLEAR REGULATORY COMMISSJON WAStUNGTON, D. c. 2osss Docket No. 50-272
~MAY 3 0 1979 LICENSEE:
PUBLIC SERVICE ELECTRIC & GAS COMPANY {PSE&G)
FACILITY:
SALEM UNIT HO. l
SUBJECT:
Sill'Ji'ARY OF HEETING HELD ON MAY 25, 1979, TO DISCUSS DA.V~E OBSERVED TO FUEL GRID ASSEMBLIES DURING THE SALEH U~IT NO. 1 REFUELING OUTAGE On 1".ay 25, 1979, we met with* representatives of Public Service Electric &
Gas Company (PSE&G) and Westinghouse to discuss the cause and extent of damage observed to the Salem Unit.No. l fuel grid assemblies during the
. current refueling outage for cycle 2.
A list of attendees is enc1osed.
Si5nific:ant discussions are suarnarized below.
- .*The license! and Westinghouse provided a detailed discussion of the dar...age observed to the Salem fuel grid assemblies during the cycle 2
_refueling outage whieh*corrrnenc:ed in April 1979.
Due to the indications_
.. observed during the initial stages of the outage, the decisi*on was made
- to unload all fue1 assemblies front the core.
Of the fuel assernbl ies _
'(193) inspectedw 28 asse.'ilblies ware determined to have varying degrees cf ~air.age to one or more of the eight grid.asse.ilbl i es per fuel assembly.
The grid asse.--:biies provide lateral support to the fuel rods.
In no case was dai:age o:-served to the fue1 rods themselves.
The grid assembly dar..age observc~lJ which was gen.era11y lo.cated at the corners of the grid ass:.:ibl ies., nas ca~egorized, as fol 1 ows:
ca~egoQ Type of Oamcge No. of Grid AssE:mbl ies 1
small pieces missing 15 2
grid *rrll:lterial ripped 4
and laid over 3
~~rger sections. missing and 9
fuel pins exposed
L r~~
Meetfng Sunrnary for SaieDt Unit 1 Atta.~hme.nt *
~:~--C.ircular. No. 80-13
.*. -Z-
. Of the above. fuel assemblies* with categories 1 and Z damage were
.. detennined by the 1 'f censee to be acceptab 1 e -for use and will be re 1 oaded forcycle2; as a precautionary measure assemblies with category 3 damage will not~ be reloaded. The basis for this detennination was that assemblies with category 1 and 2 damage can be used without any loss of function of the damaged grids. Fuel assemblies with category 3 damage; however, no longer fully restrain all fuel rods-in the manner provided for in the design. Their reuse should be based on further analysis.
Of the data co11ectt.-d and the reload films reviewed, no pattern has been established for* the observed damage. 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 corrier-to~conier interaction* may have occurred between grid assemblies of. adjacent fuel assemb1 ies especially when di~gona1 fuel assemblies. have bea...n removed and.some degree of lateral raovemen t 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 of about.25in2 is involved.
These pieces range fromabout.3in2 up to about s.-Sin2.
Approximately 12inZ of material has been recovered. from* the *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 b1ockage from the missing material, Westinghouse indicated that if a11 the peices originally missing were to be located such as to partially block the in1et nozzle
- area of the cne fuel assembl, analyses similar to that described in Section 3.4 of the Salem FSAR indicate that no probl~~ would exist. The smaller pieces still missing are expected. to easily pass up through the.
fuel assenlh1 i es during opera ti on and not present any pro bl ems to the*
r.ontrol rod drive mechanisms.
The largest that any of the.missing pieces could.be, based on the base areas on.grid assemblies, is slightly greater th~n 2in2.
h'estinghouse has reccn;;nende*~ adc!iticne.l fuel assembly handling precautions
~~'to minimize the potential for corner-to-corner interaction between grid assemblies.
Included among these recorrrnendations are, 1) a revised loading sequence "ihich would load fuel assemblies *from the sides of the core toward the center. 2) a slight offset in position as corner fuel
- assemblies are lowered into the core until they are about 10" above the base plate and then rr~king a lateral adjustment into final position.
- 3) the conditionally accepted asse~blies in categories 1 and 2 wou1d be leaded in a special sequence to minimize relative motion with adjacent.
asser.:blies, 4) those asse:nblies in category 2 w:iuld be loaded against the core baffle, -..:here possible and S) re..-ised load ce1 l limits on the mani*
pulator crane in an atte.iip-: =o r.:ore easily detect increased loads during fuel handling.
..,,)...._ -.... '. -
~eeting S~1m1ary for Sal an Unit 1 f-, -~.... '
Attachment.*
r_E Circular. No. 80-13
... ~. ~*
Westinghouse acknow1edged and sumnarize.d similar grid assembly problems
- that have occurred at other facilities.
Although these other oc.currences.
did not involve as ~.any fuel assemblies as in this Sale>> situation, similar damage has been observed to 14x14. 15xl5 and 1ix17 fuel assembli.es.
In some instances the fuel was removed, and in others. the fuel was re-loaded with no known adverse effects *
. With regard to th~ Salem Unit 1 refueling analysis~ the licensee indicated pr<=liminarfly, that the core parameters are expected to be essentially unchanged due to the revised core loading that will result.
The licensee agreed to address the potential effects that the unaccounted for pfeces of grid material might have on the core thermal hyd1*aulic analysis. and on control rod operation.
This infonnation will be included prior to restart of Sal~ 1 in a supplement to the licensee's reload application for cycle 2.
Enclosure:
L1st of Attendees cc: w/enclosure See next page
~
... *-~-*--*-- -.._.
~~~~*
Gary G. Zech. Project Mar.ager Operating Reactors Branch.#1 Division of Operating Reactors
~- __ ;..
~*- :-
.~
c-Circular No.
80-03:
80-04.
80-05 80-06 80-07 80-08 80-09 80-10 80-11 80-12 ENCLOSURE *2 IE Circular No. 80-13 Date:
May 28, 1980 Page l of 1 RECENTLY ISSUED IE CIRCULARS
. Subject
.Protection from Toxic Gas Hazards Securing Threaded Lack-ing.Devices on Safety-Related Equipment Emergency Diesel Gen-erator Lubricating Oil Addition and Onsite Supply Control and Account-ability Systems for Implant Therapy Sources Problems with HPCI Turbine Oil _System BWR Technical Speci-fication Inconsis-tency
- RPS Response Time Problems with Plant Internal Communi-cations Systems Failure to Maintain Environmental Qualification of Equipment Emergency Diesel Generator Lube Oil Cooler Failures Valve-Shaft-To-Actu-ator Key May Fall Out of Place When Mounted Below Horizontal Axis First Date of Issue 3/6/80 3/14/80 4/1/80 4/14/80 4/3/80.
4/18/80 4/28/80 4/29/80 5/13/80 5/14/80
- Issued To A 11 Power Reactor Fad 1-ities with an (Operating License (OL)
All Power Reactor Facil-ities-with an OL or CP A 11 Power Reactor Fae i 1-i ti es with an OL or CP Medical Licen~ee~ in Categories G and Gl All Power Reactor Facil-ities with an OL or CP All General Electri~
BWRs holding a power reactor OL All holders of a reactor OL or CP All Power Reactor Facilities with an OL or CP All Power Reactor Facilities with an OL or CP All Power Reactor Faci-lities with an OL or CP