ML20066H140

Special Rept 90-01:on 910125,during Annual Fuel Insp of Operational Core VIII-A,fuel Elements 6502 & 8468 Failed to Pass go-no-go Gauge Test for Excessive Transverse Bend. Elements Replaced W/Spare & Fuel Bundles Relocated

ML20066H140
Person / Time
Site:	05000128
Issue date:	02/08/1991
From:	Hall K TEXAS A&M UNIV., COLLEGE STATION, TX
To:	Beach A NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
References
90-01, 90-1, NUDOCS 9102200185
Download: ML20066H140 (5)

Text

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.u Mr. A. Bill Beach, Director Division of Radiation Safety and Safeguards U.S. Nuclear Regulatory Commission Region IV 611 Ryan Plaza Drive, Suite 1000

-1 Arlington, Texas 76011

Dear Mr. Beach:

. I am forwarding the final report of the reportable occurrence of 25 January 1991.

This report is being submitted in accordance with the reporting requirements of Technical Specification 6.6.2 for License R-83, Texas Engineering Experiment '

Station / Texas A&M University System.

Respectfully, Kenneth R. Hall, Deputy Director Texas Engineering Experiment Station Enclosure cc: D. E. Feltz, Director, Nuclear Science Center F. Jennings , Chairman, Reactor Safety Board K. L. Peddicord, Assistant Director, Texas Eng. Exp. Station J. A. Reuscher,' Director, Nuclear Research Reactor Programs, NSC S. H. Weiss, USNRC, Washington, D.C.

B. Ernst, American Nuclear Insurers i

9102200185 910200 IC PDR ADOCK 05000128 i 'e.--

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Reportable Occurrence ; # 91-01

~ Abnormal' Degradation in BeactorL Fuel

• i as Specified in Technical Specification 1.29e _ and 4.2.4d(1) 4 Description ,

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In reference to fuel: performance of the Texas En61neering Experiment Station /Texasi g, A&M University System,. . Nuclear : Science Center Reactor (NSCR), TechnicalE Specifi- ,

cation ' 4.2. 4.a specifies 'that, at least .onear.if thlor the ' fuel . elemento1 used lin:

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operation of the reactor over the previousiinspection nyear :shall bel l,inpsected :

visually- for damage or deterioration and measured for length 1and:. bend annually," notL  !

to exceed 15 months. Also, at least four : fuel elements: which occupy theDh16hesth

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pulse temperature positions ini the core L shall' be inspect'ed. These elements;may.be .!

included in the one-fif th total of elements selected and: scheduled forfinspection( -]

on 25 January '1991 during- performance of the ' annual fdel inspection; of operationali > l Cor e VIII-A -(see attached)', fuel elementLNo. 6502 located :id C-7, SE failsd toTpass -

the go-no-go gauge test for excessive trar.sverse bend as specified la iTechnical: JU Specification 4.2.4.d(1).- This specification requires that the element 'be' removed j from~ service if the measured transverse bend ' exceeds ' O 125 incheslover the.'IAngthL f

of the cladding. There is also a requirement under Technical Specification A 2.4 ,.b ,

that if any element is found to 1 be out of tolerance, the 1 entire : core : will - be1 inspected. ,

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Element No. 6502 showed no apparent visibleEdamage to; the fuel :cladd1&and' there _ 9 was no. fission product leakage detected in daily pool water samples. .Thelelement  !

was removed from service and replaced withia spare fuel element.;  ;

l L Results'or Inspection of All Ebel Elements in Ute F

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. A total of 97 FLIP- fuel elements were inspected consisting 1ofi 90 'elementsi from- the; >

reactor core and seven elements used in' rotation orLexchangeW/AllLfuel elementaLin 1 Luse . requiring 71 nspection are ~ FLIP; TRIGa- elements. . (During ?theifuel L inspection ,7 a : <

second fuel element No.- 8468 located !in .E-3, NW9 failed to_ pass the go-no-gs gaugni "

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testMror excessive tranmrse bend. This elementL also Lf50wed1 no apparentivisible  :

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damage to the fuel' cladding and,( as earlier stated,-- therp,was no detected; fission 'j

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product. leakage. i Element- No. 8468 was: also-' removed from service l andl replaceciwithi a' spare fuelhelement.

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Operating History of Bowed'Fbel Elements No. 6502 and No. 8468 Total Core

• Element Date of Late Removed Operation IntfalMass Prgs,e,nt Mass $ Pulse No. First Use From Service Mw Days- U- U Reactivity 6502 10/1/79l 1 / 2 5/ 91 1007.7 122;28- 105.89 829.4 ,

8468 1/7/77 .1 /2 5/ 91 '1224.1 121.16 101.10 829 4

- Knowledge of and Actions Taken t Owner / Operators of TRIGA 'Fbels i.o Reduce ' the Excessive Bowing of Elements The explanation for' the~ bowing of. Uranium-Zirconium-Hydride fuel ' elements -is-explained in detail in the General ; Atomics document GA-A16613, "Interpretatioir of-Damage to the i FLIP Ebel During Operation of thc' Nuclear Science Center: Reactor at' Texas A&M .Oniversity", by M. T. Simnad, G. B. West,'J. D.'Randa11',' W; J. Richards, and D. Stahl, December : 1981. Also, an'. explanation ~ and evaluation .of TRIG A fuel ,

damage . by the USNRC staff is provided ' in ' NUREG-0 947, " Safety Evaluation Report Related to Renewal of the Operating 1.icense for the Texas' A&M Universi', Research .

Reactor", ' March 1983 The excessive bowing of. both Standard TRIGA and FLIP TRIGA fuels .has . b e e n -- .

experienced in other operating reactors ~ . Oregon State- University, for example, observed the excessive bowing in two FLIP-TRIGA elements in 1987 ?andlorie FLIP TRIGA element in- 198 9 These elements were removed-from service. = General Atomicstin the past ten years also identified s veral e elements'with excessive transverse' bend th'at j required their removal from service. General' Atomics -period.'cally rotates

, individual fuel elements .in 180' increments to help reduce excessive bowing. This procedure cannot be used 'in the ' NSCR due - to a ' difference in element design.- ,The

- KSCR fue:. elettents have threaded bottom ends that screw into base *.dapters .for four rod and three rod bundles. Rotation of the element would' loosen the fuel element '

in the bundly ~ we adapter.

This is.not. permitted. In comparison, the TRIGA fuel-

- elementa used by General Atomics have smooth bottom ends:that'can be easily rotated _

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. Following recent discussions with General Atomics. representatives, it was' concluded- -;

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' that the immediate action one could take to hopefully reduce or _ prevent excessive- l

' transverse bending could be - to periodically - relocate fuel bundles .within - the core . t'

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or to relocate- single' elements within fuel bundles. This can be conveniently done; i during the annual inspections of. fuel.. This action-was initiated-in the. reloading

of Core VIII-A and the reestablishment of an operational core. The- reloading of ,

Core VIII-A was completed on 1 February .1991. r l

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