ML20206M303

Proposed Tech Specs Re RCS Surveillance Requirements for Steam Generator Tube Plugging

ML20206M303
Person / Time
Site:	McGuire, Mcguire
Issue date:	08/13/1986
From:	DUKE POWER CO.
To:
Shared Package
ML20206M299	List: ML20206M295 ML20206M303
References
TAC-61775, TAC-61776, NUDOCS 8608210097
Download: ML20206M303 (5)

Text

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' REACTOR COOLANT SYSTEM

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SURVEiLLANCEREQUIREMENTS(Continued)

All n'nplugged tubes that previously had detectable wall

- - 1) o penetrations (greater than 20%),

2)

Tubes in those areas where experience has indicated potential problems, and 3)

A tube inspection (pursuant to Specification 4.4.5.4.a.8) shall be performed on each selected tube.

If any selected tube does not permit the passage of the eddy current probe for a tube inspection, this shall be recorded and an adjacent tube shall be selected and subjected to a tube inspection. d -

In odd nron to th( 3 *7o som ple., a lt F* hbes w til be tns pecte C.

d.

The tubes selected as the second and third samples (if required by Table 4.4-2) during each inservice inspection may be subjected to a partial tube inspection provided:

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1)

The tubes selected for these samples include the tubes from those areas of the tube sheet array where tubes with imperfections were previoG31y found, and i

2)

The inspections include those portions of the tubes where imperfections were previously found.

The results of each sample inspection shall be classified into one of the following three categories:

Category Inspection Results C-1 Less than 5% of the total tubes inspected are degraded tubes and none of the inspected tubes are defective.

C-2 One or more tubes, but not more than 1% of the total tubes inspected are defective, or between 5% and 10% of the total tubes inspected are degraded tubes.

C-3 More than 10% of the total tubes inspected are degraded. tubes or more than 1% of the inspected tubes are defective.

Note:

In all inspections, previously degraded tubes must exhibit significant (greater than 10%) further wall penetrations to be included in the above percentage calculations.

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8609210097 060813 PDR ADCCK 05000369 P

pop McGUIRE - UNITS 1 and 2 3/4 4-12

REACTOR COOLANT SYSTEM e

SURVEILLANCE REQUIREMENTS (Continued) 4.4.5.4 Acceptance Criteria a.

As used in this specification:

1)

Imperfection means an exception to the dimensions, finish or contour of a tube from that required by fabrication drawings or specifications. Eddy-current testing indications below 20% of the

= W a=1 tube wall thickness, if detectable, may be considered as imperfections; 2)

Degradation means a service-induced cracking, wastage, wear or general corrosion occurring on either inside or outside of a tube; 3)

Degraded Tube means a tube containing imperfections greater than or equal to 20% of the nominal wall thickness caused by degradation; 4)

% Degradation means the percentage of the tube wall thickness affected or removed by degradation; 5)

Defect means an imperfection of such severity that it exceeds the plugging limit. A tube containing a defect is defective; 6)

Plusaing Limit means the imperfection depth at or beyond which the tube shall be removed from service and is equal to 40% of the nominal tube wall thickness.

This definition does not apply to the area of the tubestset region below the F* distance provided c/u rule is noT-dryno'ro worhin tht, F* dismnce, l

7)

Unserviceable describes the condition of a tube if it leaks or contains a defect large enough to affect its structural integrity in the event of an Operating Basis Earthquake, a loss-of-coolant accident, or a steam line or feedvater line break as specified in 4.4.5.3c, above; 8)

Tube Inspection means an inspection of the steam generator tube from the point of entry (hot leg side) completely around the U-bend to the top support of the cold leg; and NOTE 1:

The application of F*

exp/res cre the engo/ rhe fifr/s l

feel cycle fo,. eacA respective unir; McGUIRE - UNITS 1 and 2 3/4 4-14

REACTOR COOLANT SYSTEM SURVEILLANCE REQUIREMENTS (Continued) 9)

Preservice Inspection means an inspection of the full length of each tube in each steam generator performed by addy current techniques prior to service to establish a baseline condition of the tubing. This inspection shall be performed after the field hydrostatic test and prior to initial POWER OPERATION using the equipment and techniques expected to be used during subsequent inservice inspections.

10)

F* Distance is the distance into the tubesheet from the top face of the tubesheet or the top of the last hardroll, whichever is lower (further into the tubesheet) that has been conservatively chosen to be 2 inches.

0 (insen a ttoc.hed) b.

The steam generator shall be determined OPERABLE after completing the corresponding actions (plug all tubes exceeding the plugging limit and all tubes containing through-wall cracks) required by Table 4.4-2.

4.4.5.5 Reports Within 15 days following the completion of each inservice inspection of a.

steam generator tubes, the number of tubes plugged in each steam generator shall be reported to the Comission in a Special Report pursuant to Specification 6.9.2; b.

The complete results of the steam generator tube inservice inspection shall be submitted to the Commission in a Special Report pursuant to Specification 6.9.2 within 12 months following the completion of the inspection. This Special Report shall include:

1)

Number and extent of tubes inspected, 2)

Location and percent of wall-thickness penetration for each indication of an imperfection, and 3)

Identification of tubes plugged.

c.

The results of inspecttons of F" tubes sha ll le. repectect to the.

the (OmmiSS fo N in O, report to the. " Director 3 ONRR prcoc to sho ll of the untdo llcwing Tbt insp(Crion. This re.p e rt re s tort in clu de :

0 IdentLfic.arron of F tubes, and

2) Locotton and inditosed depth. of the degradation.

l Amendment No.

(Unit 1)

McGuTRE - VMITs i and 2 3/4 4-/S Amendment No.

(Unit 2) r

F* TUBE is a tube with degradation equal to or greater than 40% below the F*

distance and not degraded in the F* distance.

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REACTOR COOLANT SYSTEM BASES j

3/4.4.4 RELIEF VALVES 1

The power-operated relief valves (PORVs) and steam bubble function to relieve RCS pressure during all design transients up to and including the design step load decrease with steam dump. Operation of the PORVs minimizes the undesirable opening of the spring-loaded pressurizer code safety valves.

Each PORV has a remotely operated block valve to provide a positive shutoff capability should a relief valve become inoperable.

3/4.4.5 STEAM GENERATORS The Surveillance Requirements for inspection of the steam generator tubes ensure that the structural integrity of this portion of the RCS will be main-tained. The program for inservice inspection of steam generator tubes is based on a modification of Regulatory Guide 1.83, Revision 1.

Inservice inspection of steam generator tubing is essential in order to maintain surveillance of the conditions of the tubes in the event that there is evidence of mechanical damage or progressive degradation due to design, manufacturing errors or inservice conditions that lead to corrosion.

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Inservice inspection of steam generator tubing also provides a means of characterizing the nature and cause of any tube degradation so that corrective measures can be taken.

The' plant is expected to be operated in a manner such that the secondary coolant will be maintained within those chemistry limits found to result in negligible corrosion of the steam generator tubes.

If the secondary coolant i

I chemistry is not maintained within these limits, localized corrosion may likely result in stress corrosion cracking. The extent of cracking during plant operation would be limited by the limitation of steam generator tube leakage between the Reactor Coolant System and the Secondary Coolant System (reactor-to-secondary leakage = 500 gallons per day per steam generator).

Cracks having a reactor-to-secondary leakage less than this limit during operation will have an adequate margin of safety to withstand the loads imposed dur_ing nonsal operation and by postulated accidents. Operating plants have demonstrated that reactor-to-secondary leakage of 500 gallons per day per steam generator can readily be detected by radiation monitors of steam generator blowdown.

Leakage in excess of this limit will require plant shutdown and an unscheduled inspection, during which the leaking tubes will be located and plugged.

Wastage-type defects are unlikely with proper chemistry treatment of the secondary coolant. However, even if a defect should develop in service, it will be found during scheduled inservice steam generator tube examinations.

Plugging will be required for all tubes with imperfections exceeding the g

Steam generator plugginglimitof40%ofthetubenominalwallthickness1capabilityto tube inspections of operating plants have demonstrated the reliably detect degradation that has penetrated 20% of the original tube wall l

thickness.For ru6ss w,th deg radama, 60. rLe r* d cranee, L in tko free non reycn aid' Plo39 ng is no r repired',

2o *7a wer kin tk F" d nvarce.

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McGUIRE - UNITS 1 and 2 8 3/4 4-3

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