ML20084D310

AO 4-73-10:on 730815,part Length Control Rods Inserted in Reactor Core 4 Position 81 Steps Above Bottom of Core Which Is in Violation of Tech Specs.Caused by Personnel Error. Length Control Rods Withdrawn

ML20084D310
Person / Time
Site:	Turkey Point
Issue date:	08/23/1973
From:	Schmidt A FLORIDA POWER & LIGHT CO.
To:	Oleary J US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20084D284	List: ML20084D310
References
AO-4-73-10, NUDOCS 8304110060
Download: ML20084D310 (4)

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Directorate of Licensing U.S. Atomic Pnergy Commission Unshington, D. C. 205';5 TURREY FOIr? U; IT NO. 4 DOCI:ET NU:/.D 3 50 - 251 ABNOh,I OCCU ne ' :Ci I:0. 4-73-10

_II:Si RTIO': Or' PART LE , ,Til CO:: TROL RODS

Dear Ilr. O' Leary:

I. INTRODUCTION This repurt is submitted in accordance with Technical Spacification 6.6.2.c for Turkcy Point Unit I:o. 4, Operating Licensa No. DPR-41. This Abnormal occurrence Report No. 4-73-10 describos an abnormal occurrence which was identified on August 15, 1973. The Direc-torate of Regulatory Operations was notified on August 15, 1973.

e s II. DESCRIPTIO:: OF OCCURRI":CE On August 15, 1973, in preparation for performing test -

number T-0201.12-ROD CONTROL CLUSTER ASSEMBLY PSEUDO UJECTIO:'; TEST AT 500 REACTOR PO'v:ER LEVEL, the part length concrol rods were inserted in No. 4 reactor core to a position 81 steps above the bottom of the core. ,

Changes to Turkey Point Unit Nos. 3 and 4 Technical Specifications prohibit the insertion of part length control rods during the first tuel cycle, except for low pmer phy' sics tests and axial offset calibration tests performed below 75% of rated power. Therefore, the insertion of part leng th control rods for the perfornance of test number T-0201.12 is a violation of Technical Spacification 3.2.1.e.

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August 23, 1973 III. N:AL'/ SIS o!' Tiln OCCtHIRE :CH Turkcy Point Unit No. 4 is nLill undergoing startup and polar escalation te;*s which are performed to verif y nuclea r dr' sign predicLio:is and specifications.

Test numbar T-0201.12 uns deqig'.rc.d to verify nuclear design predictions of effects on core reactivity and i poucr distribution when a rod control cluuter assembly has been " ejected" fro:a the controlling bank. A similar test was performed at approximately 57. reactor power level.

The procedure for test number T-0201.12 was identical to the test parforr.ed on No. 3 reactor to verify nuclear decign predictions. Ho' . a ve r , No. 3 reactor test was comuleted bafora the Technical Specifientions

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vere change [ to consider the offacts of fue] densifi-cation and the procedure had not been reviewed to de t erIaine if the procedure conformad to the revised Technical Spccifications.

IV. CDRRECTIVE AC'0 ION TO PICVENT RECUidtE:!CC Immadiate corrective action wa" to withdraw the part length control rods from !!o. 4 reactor core.

The part length control rods have been placed under administrative control in accordance with Administrative Procedure 0103.5. This action will prevent inadverbent insertion of the part length control rods.

A knowledgeable plant staff member has been assigned the responsibility to review the impact of technical specification changes on procedures and to recorr nond changes to procedures as required by the revised tech-nical specifications.

These actions will mininize the probability of a recurrance of this and similar incidents.

V. ANALYSIS AND EVALUATIO:: OF _ SAFETY IMPLICATIONS OF THE OCCUD M CC An evaluation of the results of analyses on the effects of fuel densi fication concluded that limitations on

l . Mr. John P. O'Lt y, Director liugust 23, 1973 operation of Turkey Point Unit ::03. 3 and 4 should be imposed. I.ccordingly, Technical Specifications were changed to provide for protection against the effects of fuel densification. These change, included limita-tions on the ma :inu:a reactor p'nter level perlaitted, li mi ta tion:, on fuel residence timo for Cycle 1, increased surveillanco requirercants to prevent operation with micaligned control rous, inop :rabl e control roda, and control rod incertio: below the incertion Jinit. In addition, insertion of part length control rods was prohibited during fuel Cycle 1  : cept for a::ial of fset calibration tacts beloa 75? rated po'ar and low power physics' tc:.us.

The basis for prohibitina the use of part length control rods during fu;l Cycle 1 ic to p2: ovide f or }?rotection against potential adverse a:ial powar distribution in the reactor core during normal operation and anticipated transients. Continued operation with part length rods innerted could recult in e::cencive paak local power dennity or mininum D::BR. It was recognized that insertion of the part length control rods for short periode ic necuandry for a::ial offset calibration tests and to perform physica testu.

While the part length control rods were incerted in No. 4 reactor core the reactor uas protected by increased operator surveillance of neutron monitors and flu:.

difference indicators. If an abnorrc.al po.:er shapo had developed, the operator would have withdrawn the part length control rods to protcct the reactor againct exces-sive axial power distribution in the reactor core.

, 1 In addition, while the part length control rods were inserted in Co. 4 reactor core, the automatic reactor protection system was operable and would have initiated ,

protective action if an abnormal power distribution had developed and the operator did not respond promptly to protect the reactor core.

Measured Unclear Enthalpy Rise Hot Channel Factor and Total Heat Flu: Hot Channel Factor at approximately 5% reactor power level vere determined to be well within acceptable limits, with the part length control rods incerted to 81 steps above the bottom of the core.

Extrapolation of this data to 500 reactor power level provides assurance that peaking factors with the part length control rods inserted to 81 steps from the bottom of the core were well within acceptable limits and the safe operat, ion of the reactor was not adversely affected.

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- Mr. J % n l'. O' Leary, Director August 23, 1973 VI. CONCL__US 10' S

a. Insert. ion of part length control rods in preparation for parf or:aance of test number T-0201.12 violated Technical Speci fi ca tions because the primary purpose of this test was not for axial offset calibration.

b. This, abnormal occurrence did not adversely affect the safe operation of Turkey Point Unit No. 4.

c. A<signrent of a knowledgeable staff member to revieu the ilapact of changes in Technical Specifications, plant procc:iares , and to recor.nand changes to these procedures to ensure conformance with the revised Technical Specifications vill minimize or prevent recurrence of this and similar incidents.

d. Placing the part length control rods under admini-strative control in accordance with Ad:ainis trative Procedure I;o. 0103.5 will prevent inadvertent operation of the part length control rods.

c. W.: e n the part length rods were inserted in No. 4 reactor core, the reacLor ;;as protected against adverse axial power distribution by increased operator surveillance and automatic actions of reactor protection system. Therefore, the safe operation of the reactor was not adversely affected.

f. This abnormal occurrence did not present any danger to the public health and safety. s Very truly yours, ,

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A. D. Schmidt Director of Power Resources i ADS /JICH/AF]I/VTC/bfs cc: Mr. Norman C. Moseley, Director Region II, Dire'ctorate of Regulatory Operations U. S. Atomic Energy Commission Sui te 018, 230 Peachtree Street, N.W.

Atlanta, Georgia

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Directorate of Licensing U.S. Atomic Energy Commission Washington, D. C. 20545 TURKEY POINT UNIT NO. 4 DOCKET NUMBER 50 - 251 ABNORMAL OCCURRENCE NO. 4-73-10 INSERTION OF PART LENGTH CONTROL RODS

Dear Mr. O' Leary:

I. INTRODUCTION This report is submitted in accordance with Technical Specification G.6.2.a for Turkey Point Unit No. 4, Operating License No. DPR-41. This Abnormal Occurrence Report No. 4-73-10 describes an abnormal occurrence which was identified on August 15, 1973. The Direc-torate of Regulatory Operations was notified on August 15, 1973.

II. DESCRIPTION OF OCCURRENCE On August 15, 1973, in preparation for performing test number T-0201.12-ROD CONTROL CLUSTER ASSEMBLY PSEUDO EJECTION TEST AT 50% REACTOR POWER LEVEL, the part length control rods were inserted in No. 4 reactor core to a position 81 steps above the bottom of the core. ,

Changes to Turkey Point Unit Nos. 3 and a Technical Specifications prohibit the insertion of part length control rods during the first fuel cycle, except for low power physics tests and axial offset calibration tests performed below 75% of rated power. Therefore, the insertion of part length control rods for the performance of test number T-0201.12 is a viola ion of Technical Specification 3.2.1.e. c f'dy V3 N Duge o+ -9'v ^ ". a w "cn -

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O Mr. John F. O' Leary, Director August 23, 1973 III. ANALYSIS OF THE OCCURRENCE Turkey Point Unit No. 4 is still undergoing startup and power escalation tests which are performed to verify nuclear design predictions and specifications.

Test number T-0201.12 was designed to verify nuclear design predictions of effects on core reactivity and power distribution when a rod control cluster assembly has been " ejected" from the controlling bank. A similar test was performed at approximately 5% reactor power level.

The procedure for test number T-0201.12 was identical to the test performed on No. 3 reactor to verify nuclear design predictions. However, No. 3 reactor test was completed before the Technical Specifications were changed to consider the effects of fuel densifi-cation and the procedure had not been reviewed to determine if the procedure conformed to the revised Technical Specifications.

IV. CORRECTIVE ACTION TO PREVENT RECURRENCE Immediate corrective action was to withdraw the part length control rods from No. 4 reactor core.

The part length control rods have been placed under administrative control in accordance with Administrative Procedure 0103.5. This action will prevent inadvertent insertion of the part length control rods.

A knowledgeable plant staff member has been assigned the responsibility to review the impact of technical specification changes on procedures and to recommend changes to procedures as required by the revised tech-nical specifications.

These actions will minimize the probability of a recurrance of this and similar incidents.

V. ANALYSIS AND EVALUATION OF SAFETY IMPLICATIONS OF THE OCCURRENCE An evaluation of the results of analyses on the effects of fuel densification concluded that limitations on S

/'\ U (s Mr. John F. O' Leary, Director August 23, 1973 operation of Turkey Point Unit Nos. 3 and 4 should be imposed. Accordingly, Technical Specifications were changed to provide for protection against the effects of fuel densification. These changes included limita-tions on the maximum reactor power level permitted, limitations on fuel residence time for Cycle 1, increased surveillance requirements to prevent operation with misaligned control rods, inoperable control rods, and control rod insertion below the insertion limit. In addition, insertion of part length control rods was prohibited during fuel Cycle 1 except for axial offset calibration tests below 75% rated power and low power physics tests.

The basis for prohibiting the use of part length control rods during fuel Cycle 1 is to provide for protection against potential adverse axial power distribution in the reactor core during normal operation and anticipated transients. Continued operation with part Jength rods inserted could result in excessive peak local power density or minimum DNBR. It was recognized that insertion of the part length control rods for short periods is necessary for axial offset calibration tests and to perform physics tests.

While the part length control rods were inserted in No. 4 reactor core the reactor was protected by increased operator surveillance of neutron monitors and flux difference indicators. If an abnormal power shape had developed, the operator would have withdrawn the part length control rods to protect the reactor against exces-sive axial power distribution in the reactor core.

In addition, while the part length control rods were inserted in No. 4 reactor core, the automatic reactor protection system was operable and would have initiated protective action if an abnormal power distribution had developed and the operator did not respond promptly to protect the reactor core.

Measured Nuclear Enthalpy Rise Hot Channel Factor and l Total Heat Flux Hot Channel F. actor at approximately I 5% reactor power level were determined to be well within acceptable limits, with the part length control rods inserted to 81 steps above the bottom of the core.

Extrapolation of this data to 50% reactor power level provides assurance that peaking factors with the part I length control rods inserted to 81 steps from the i bottom of the core were well within acceptable limits and the safe operation of the reactor was not adversely ,

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• Mr." John F. O' Leary, Director August 23, 1973 VI. CONCLUSIONS

a. Insertion of part length control rods in preparation for performance of test number T-0201.12 violated Technical Specifications because the primary purpose of this test was not for axial offset calibration.

b. This abnormal occurrence did not adversely affect the safe operation of Turkey Point Unit No. 4.

c. Assignment of a knowledgeable staff member to review the impact of changes in Technical Specifications, plant procedures, and to recommend changes to these procedures to ensure conformance with the revised Technical Specifications will minimize or prevent recurrence of this and similar incidents.

d. Placing the part length control rods under admini-strative control in accordance with Administrative Procedure No. 0103.5 will prevent inadvertent operation of the part length control rods.

c. When the'part length rods were inserted in No. 4 reactor core, the reactor was protected against adverse axial power distribution by increased operator surveillance and automatic actions of reactor protection system. Therefore, the safe operation of the reactor was not adversely affected.

f. This abnormal occurrence did not present any danger to the public health and safety.

Very truly yours, g,jswW l A. D. Schmidt l Director of Power Resources .*

ADS /JKH/AFH/VTC/bfs i cc: Mr. Norman C. Moseley, Director l Region II, Directorate of Regulatory Operations i U. S. Atomic Energy Commission l Suite 818, 230 Peachtree Street, N.W.

i Atlanta, Georgia

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