ML19317F369

Reactor Vessel Internals Insp Following Hot Functional Testing

ML19317F369
Person / Time
Site:	Oconee
Issue date:	01/25/1974
From:	DUKE POWER CO.
To:
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ML19317F368	List: ML19317F367 ML19317F369
References
NUDOCS 8001140622
Download: ML19317F369 (7)

Text

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DUKE P0WER C0MPANY OCONEE NUCLEAR STATION UNIT 2 Docket No. 50-270 REACTOR VESSEL INTERNALS INSPECTION FOLLOWING HOT FUNCTIONAL TESTING January 25, 1974

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s 1.0 lNTRODUCTION!

-.This report presents' lnfortnation requested by :the Atomic Energy Commission,

' Safety Guide--20, with regard-to the Oconee Nuclear Station, Unit 2, reactor

vessel. internals..~ The prototype design-for the Oconee 2 reactor vessel

? internals was the"Oconee 1 internals. A comprehensive report on vibration

' measurement:results for these prototype internals was submitted to the AEC cin April, 1973,'as_ Topical Report BAW-10039, " Prototype Vibration Heasure--

ment LResults for 'Br,W's 177-Fuel-Assembly,- Two-Loop Plant." ' This Topical Report was~ Incorporated into the~ Oconee~ Final Safety Analysis Report by reference.by-Revision 28,IMay 1,-11973

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SUMMARY

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} HotiFunctionII.? Testing of Oconee : Nuclear Statlon,' Unit ' 2,~ was; conducted f rom'

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-qJuly 30,;1973;/through Sept'mber 18,fl973.

During'this period a; total of e

z 7313.80Thours;were? logged Wtielevated. temperature and pressure,' full l flow

'condi tions',ji.e.,u four ' reactor; coolant ~ pumpsfoperating and the. Reactor Coolant

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System (atiappr ximately'530 Fjand 2155

psig.

Consequently,Jthe?thermaljshleid,

'which.had the i more than:1107;:.: lowest m2asured -structural frequency l(12 Hz), was subjected to cyclesfunder lthese conditions.. The reactor ' internals. were -

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also.subjecte'd!to:co'nsiderable, addItlona11 hours at flow: conditions other y

~ ~than : those - i dent i f ie'd ' above. - This? time was more than sufficient to accumu =

11 ate'an additional 107 cycles.of vibration'on the: thermal shield.

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Following: the Econclusl' n of Oconee 2 Hot.Functlonal Testing,. the.reactore o

-InternalsLwere1 removed;from'the vessel'and a post-test: inspection program.

fwas: Implemented.-LThe purpose'ofitbis-' program was~to' visually' inspect major internals,- surfaces and/or parts: for. any indications of distress.,: loose

' parts, -cracking,1 fretting or. distortlon. as: a-resul t of Hot' Functional:

'Testingh -It was! determined that th' reactor internals sustained no structural e

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'! damage due to Hot' Functional Testing and that no deterioration had occurreof that might affect theistructural integrity of the internals.

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,j (DESCRIPT10N'0F PROGRAM -

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s GThe' reactorSinternalsisupport the-core,1 maintain fuel; assembly alignment,.

Climit;fue1Tassemblyl:movementiand maintain control rod ' assembly guide tube

alignment;between fuel

assemblies and control;; rod drives.

They also direct the flow'of reactorJcoolant,- provide. gamma?and neutron shielding,l provide s-Cguides for sincore. Iristrumentationl betweenithe -reactor vessel lower head and

?the:fdel; assemblies,;supportithe: surveillancejspecimen ' assemblies in the annulus 1between the; thermal?shleid and.the reactor vessel; wall and support the'1 Internals ventivalves..:The general' arrangement of the' internals is g

~ shownfinFigurej.l.;

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)The-internalicomponent's'inclu'dethe.plehdmassembly'and-thecoresupport-fassembly, f The -plenum assembly-consistshof1the plenum cover,- upper-grid, controlirod2 assembly guide:tubelassemblies'~and a flanged plenum cylinder

' with openin'gs 'for reactor. coola'nt outlet flow..The core support assembly

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31ncludest the' core support-; shleid,n vent valves, core barrel, lower grid, flow idistributor, incore instrument guide tubes,. thermal shield and surveillance specimen holder tubes.

Follo$ing Hot.Functlonal, Testing, the reactor-vessel internals were visually

. inspected for. anylindications of ~ distress, loose parts, cracking, fretting or distortioni. Items. checked toiassure the structural integiity of the l'ternals included theifollowing:

n (a)lThe plenum cover for weld integrity.

.(b) The c6ntrol-rod guide: thbe assembly to plenum cover welds for integrity.

'(c)[The bol.ted joints between.t_he control r6d'gulde tube assemblies and'the

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s pper gridi for loose -or broken bolts' and for ' lock weld integrity.

u (d)(The boltedjjoint between the upper grid and the plenum.-cylinder for -

loose or, broken :bol ts and ~ for ilock wel.d integrity.

(e) The control rod guide. tube assembiles-for weld integrity.

(f). The; internals ventivalves :: for free' operation.

- (g)l The s'urveillance specimen : holder L tubes for f ree-'rotatlon.

l (h) 7The bol'ted[:' Joint:betweenothe core support shield and the core barrel for-loose:orj broken. bolts;and for)1ock weld ; integrity.

1(1):Thi coreTsupport shield: for weld -Integrity.

i (J)lTde icore support assembly guide blocks; for weld integrity. -

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~ ((k)iTh@ind6rellrstrumeht? nozzles for distortion.

?(1) Theilncor;eHnstrument: guide tubes to flow distributor welds for

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(ri) The lober grid and ' fIcu dis tributs.r for weld integrity.

LTypical_ittms chec'ked for signs of fretting or surface damage included:

~(a) The internals vent valves seats.

(b) The face-seals of the 36" reactor vessel outlets.-

(c) The control ' rod guide tube assemblies.

(d) The plenum assembly key ways.

(c)-The core support assembly key ways.

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(f) The core support assembly guide blocks.

(g) The reactor vessel' guide lugs.

In addition to the above inspections,. examinations were also made to determine if there were any loose or. foreign objects within the reactor

vessel, in particular, these included a check of the interior of the

. reactor vessel lower head and a check of the interior of the plenum assembly.

The.various inspections performed were similar in type and extent to those performed on the Unit 1 internals following Unit i Hot functional Testing.

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DESCRIPTION OF~FESULTS 4.0 l

post-Hot Functional Testing inspection of the Oconee 2 reactor vesse No integrity degradation.

The internals revealed no indications of structural in those loose.or broken bolts or cracked or broken welds were observed.No significant areas examined, no loose or foreign objects were observed.

indications of fretting or surface damage were noted.

In general, the reactor internals sustained no structural damage due to might affect the Hot Functional Testing and no deterioration occurred that structural integrity of the internals.

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