ML20084H482

AO BFAO-7443W:on 740717,MAPLHGR Calculated to Be Above Tech Spec Limits After Completion of Full Set of TIPs

ML20084H482
Person / Time
Site:	Browns Ferry
Issue date:	07/26/1974
From:	Eric Thomas TENNESSEE VALLEY AUTHORITY
To:	Oleary J US ATOMIC ENERGY COMMISSION (AEC)
References
AO-BFAO-7443W, NUDOCS 8305040331
Download: ML20084H482 (3)

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TENNEGSEE C -!ATTANOCGA,VALLEVAUTHO TEIJNEi3SEE AiTY E ! P 77 r'\\

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July 26, 1974

'_J ANNIVE F d c AY

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%u w- i *,-;nb h T  !% '%rA Mr. John F. O'Lonrf, Director f:.EN4,5,891974 tA 7 Directorate of Licensing f. L q* -' %f Office of Regulation o p ~7 U.S. Atomic Energy Cor: mission Washington, DC 20545 kgf.j],~ f j('S . ', :Q /

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Dear Er. O' Lear /:

TEiTITESSEE VI,LLET /W:IO2ITI - BROiTJS FL7RY I!UCLZtR PLM T UITIT 1 -

DOCl3T I!O. 50-259 - FlCILITf OP2?J.TII:G LICZTS2 JPR A3:iORML OCCURPJ2;CE R3 PORT B71.0-7443F7 The encloced report is to provide details concerning the taximura cycrnce plcner linear hett generction rcte (IG.PLL:GR) which was enlculated to be 14.47 :d!/ft ts cc: pared to a linit of 14.35 kil/ft efter corrpletion of a full set of TIP's at 1500 hours0.0174 days <br />0.417 hours <br />0.00248 weeks <br />5.7075e-4 months <br /> on u

July 1*/, 1974,end is submitted in accordence with !.ppendix A to Regulatory Guide 1.16, Revicion 1, October 1973 This event occurred on "rr.mn ?cvvf Un n1 - m mt uau 1 en J&y 17,1^7':.

Very truly yours, ,

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Director of Power Production Enclosure CC (Enclosure):

1'r. IIorman C. I:cceley, Director Region II Regulatory Operntions Office, USla:C 230 Peachtree Street, IT,I. , Suite 818 -

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ABNORIC1 OCCURRE! ICE REFORT Report IIo.: BFAo-7443W Report Date: July 26, 1974 Occurrence Date: July 17, 1974 Fecilit'/: Browns Ferry liuclear Plant unit 1 g entification of Occurrence After co:pletion of a full set of TIP's at 1500 hours0.0174 days <br />0.417 hours <br />0.00248 weeks <br />5.7075e-4 months <br /> on July 17, 1974, the maxicxa averac plcnar linear heat generation rate (IIAPUIGR) was calculated to be 14.47 k ft as co= pared to a limit of 14.35 kW/ft. ,

Conditions Prior to Occurrence The reactor had been operating at 100-percent power since July 4,1974. The II.APIEGR calculated before the TIP set was 14.03 kW/ft.

Descrintion of Occurrence Before the full set of TIP's on July 17, 1974, 500 EFFH had elapsed since the previous full set of TIP's was run on June 14, 1974. Technical specification requires TIP set to be run at intervals not to exceed 1,000 EFFH.

During the period June 14 to Jul,y 17, there were several relative 4 minor at urtment t n v.n a conrmn> ron prr.r,ern. bul Ge infomation f20m Lhe June 14 TIP set was considered adequate. All other core pareneters remained well within limits before and e.fter the July 17 TIP's as illustrated in the following tabic:

Before July 17 After July 17 After July 18 TIP Set ,

Limit TIP Set TIP Set And Rod Insertions Minimum critical 1.9 2.34 2.43 -

2.47 heat flux ratio .

Peak Heat 18.5 ' 17.2 17.5 16.9 Flux kW/ft Peaking 2.63- 2.465 2.516 2.437 Factor  ; i

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l MAPUlGR 14.35 14.03 14.47 ,

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Descriution of Occurrence (centinued) --

A review of core evaluations revealed that application of the 0.W kW/ft error in MiPIJDR to previous data resulted in the steady-state violation first occurring at 0330 on July 17, 1974 Desir nation of Annarent Cause of Occurrence An error in judgecnt occurred. F. ore car 16 n should have been maintained bet.ecn calculated cnd limiting :02 2GR values under these conditions.

Analysis of Occu rence Technical specification 3 5.I on FJ.PIJUR e.ssures that the peak cladding temperature following the postulated design basic loss-of-coolant accident will not eneeci the 2,3co I'. limit spceified in the Interin Acceptance criteria (IAc) icaued in June 1971. A reilsed I';2IZIGR curve uns subnitted to AEC on June 3,197h, which justifies approxi_ately 8-percent additional carcin for the current core exposure. Since the current limit was exceeded by only 0.8 percent, a violation of the technical basis for this requirement did not occur.

Corrective Action

- An adjustnent to the rod pattern was acco=plished 4 ediately by inserting control' rods. The F. API 2GR dropped to 13.84 kW/ft. The reactor remained nt LOO-percent pouer. Responsible engineers have been instructed to maintain a more conservative nargin between actual -A hing values of I'ApIJDR.

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