ML18227D394

08/25/1978 Letter Attached Report of Abnormal Indications from Metal Impact Monitoring System, Which Occurred During Unit Cooldown for Refueling

ML18227D394
Person / Time
Site:	Turkey Point
Issue date:	08/25/1978
From:	Robert E. Uhrig Florida Power & Light Co
To:	Schwencer A Office of Nuclear Reactor Regulation
References
Download: ML18227D394 (5)

Text

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DISTRIBUTION FOR INCOMING MATERIAL 51 REC: SCHWENCER A ORG,'HRIG R E DGCDATE: 08/25/78 NRC FL PWR 8( LIGHT DATE RCVD: 09/01/78 DOCTYPE: LETTER NOTARIZED: NO COPIES RECEIVED

SUBJECT:

LTR 3 ENCL 3 FORWARDING EVALUATION PURSUANT TO REQUIREMENTS OF ORDER FOR MODlFICATION OF LIC DTD 08/02/77 ENTITLED: "REPT GF ABNORMAL INDICATIONS FROM METAL IMPACT MONITORING SYSTEM TURKEY POINT UNIT NO 4. "

PLANT NAME: TURKEY PT N4 REVIEWER INITIAL: X JM DISTRIBUTOR INITIAL: g 444~)444++>444~4<H~ DISTRIBUTION GF THIS MATERIAL IS AS FOLLOWS I

GENERAL DISTRIBUTION FOR AFTER ISSUANCE OF OPERATING LICENSE.

(DISTRIBUTION CODE A001)

FOR ACTION: BR CHI EF ORBN1 BC~i +W/7 ENCL INTERNAL: NRC PDR++W/ENCL OELD4~LTR ONLY HANAUER~~W/ENCL CORE PERFORMANCE BR+~W/ENCL AD FGA SYS u) PROJk<W/ENCI ENGINEERING BR<<4W/ENCL REACTOR SAFETY BR~~W/ENCL PLANT SYSTEMS BR+>W/ENCL EEB<4W/ENCL EFFLUENT TREAT SYS<<W/ENCL J. MCGOUG)B ~W/ENCL EXTERNAL: LPDR'S MIAMI, FL+~W/ENCL TERA++W/ENCL NSI C4~4 W/ENCL ACRS CAT B++W/ih ENCL DISTRIBUTION: LTR 40 ENCL 39 CONTROL NBR: 782440047 SIZE: iP+1P

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0 h~...e FLORIDA POWER 84 LIGHT COMPANY I

4I August'5,'"'978 L 78-278 I

f Office of Nuclear Reactor Regulation Attention: Mr. A. Schwencer, Chief Operating Reactors Branch gl Division of Operating Reactors U. S. Nuclear Regulatory Commission Washington, D. C. -

20555

Dear Mr. Schwencer:

Re: Turkey Point Unit 4 Docket No. 50-251 Metal Im act Monitorin S stem The Order for Modification of License for Turkey Point Unit No. 4, dated August 2, 1977, amended paragraph 3.D of License DPR-41. Pursuant to the requirements of this Order, Florida Power 6 Light Company is for-warding the attached evaluation "Report of Abnormal Indications from Metal Impact Monitoring System, Turkey Point, Unit No. 4." The indications occurred on August 13, 1978 during the unit cooldown for refueling.

Very t y yours, Robert E. Uhrig R g Vice President I ll REU/RJA/mal II

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.REPORT OF ABNORMAL INDICATIONS FROM METAL XMPACT MONITORING SYSTEM (MIMS)

TURKEY POINT UNXT 4 August 13, 1978 On August 13, 1978, while Turkey Point, Unit 4 was cooling down for a scheduled refueling outage, the MIMS alarmed 6 times during a one hour period. The 6 events were all separate, single, low energy indications. No other alarms were experienced during the remainder of the cooldown.

Our review of the MXMS data concluded that the most prob-able cause of the alarms was normal acoustic emissions produced by the reactor vessel during periods of changing pressure and temperature.

Upon shutdown, tubesheet photographs of all 3 steam gen-erators verified that no tube plugs had become loose.

This information supported the conclusion that the indi-cations were not caused by loose parts. However, if assumption is made that the alarms were caused by a loose the part(s), the separate, low energy impacts indicate a single object. This is consistent with prior NIMS indi-cations on this unit. This information, along with the continuing commitment of performing core barrel motion measurements after unit heat up, and for continued loose parts monitoring, ensures continued safe operation of Turkey Point Unit 4.