ML20212B866

Proposed Tech Specs,Incorporating Revised Steam Generator Plugging Criteria

ML20212B866
Person / Time
Site:	Mcguire, McGuire
Issue date:	08/05/1986
From:	DUKE POWER CO.
To:
Shared Package
ML19292F701	List: ML20212B858 ML20212B866 ML20212B874 ML20212B884
References
TAC-61775, TAC-61776, NUDOCS 8608070255
Download: ML20212B866 (7)

Text

1 REACTOR COOLANT SYSTEM A/o 3/4.4.5 STEAM GENERATORS g

LIMITING CONDITION FOR OPERATION .

3.4.5 Each steam generator shall be OPERA 8LE.

APPLICA8ILITY: MODES 1, 2, 3 and 4.

ACTION:

With one or more steam generators inoperable, restore the inoperable generator (s) to OPERABLE status prior to increasing T,yg above 200*F.

SURVEILLANCE REQUIREMENTS 4.4.5.0 Each steam generator shall be demonstrated OPERABLE by performance of the following augmented inservice inspection program and the requirements of Specification 4.0.5. -

! 4.4.5.1 Steam Generator Sample Selection and Inspection - Each steam generator shall be determined OPERABLE during shutdown by se!ecting and inspecting at <

least the minimum number of steam generators specified in Table 4.4-1.

4.4.5.2 Steam Generator Tube Sample Selection and Inspection - The steam generator tube minimum sample size, inspection result classification, The and the I. corresponding action required shall be as specified in Table 4.4-2.

l inservice inspection of steam generator tubes shall be performed at the fre-l quencies specified in Specification 4.4.5.3 and the inspected tubes shall beThe j verified acceptable per the acceptance criteria of Specification 4.4.5.4.

i tubes selected for each inservice inspection shall include at least 3% of the total number of tubes in all steam generators; the tubes selected for these l

inspections shall be selected on a random basis except:

j I a. Where experience in similar plants with similar water chemistry indicates critical areas to be inspected then at least 50% of the l

tubesinspectedshallbefromthesecritical. areas; l-

b. The first sample of tubes selected for each inservice inspection (subsequent to the preservice inspection) of each steam generator j shall include:

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8600070255 860805

. PDR ADOCK 05000369 P PDR i

McGUIRE - UNITS 1 and 2 3/4 4-11

REACTOR COOLANT SYSTEM No day SURVEILLANCE REQUIREMENTS (Continued)

1) All n'nplugged o tubes that previously had detectable wall 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,thisshallberecordedandanadjacenttubeshall be selected and subjected to a tube inspection,

c. 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:

1) The tubes selected for these samples include the tubes from those areas of the tube sheet array where tubes with imperfections were previou51y found, and

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.

J C-3 More than 10% of the total tubes inspected are l

l' 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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McGUIRE - UNITS 1 and 2 3/4 4-12 l

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ko }Ol b REACTOR COOLANT SYSTEM SURVEILLANCE REQUIREMENTS (Continued) 4.4.5.3 Inspection Frequencies - The above required inservice inspections of steam generator tubes shall be performed at the following frequencies:

a. The first inservice inspection shall be performed after 6 Effective ,

Full Power Months but within 24 calendar months of initial criticality.

Subsequent inservice inspections shall be performed at intervals of not less than 12 nor more than 24 calendar months after the previous inspection. If two consecutive inspections following service under '

AVT conditions, not including the preservice inspection, result in all inspection results falling into the C-1 category or if two consecutive inspections demonstrate that previously observed degra-dation has not continued and no additional degradation has occurred, the inspection interval may be extended to a maximum of once per 40 months; .

i b. If the results of the inservice inspection of a steam generator conducted in accordance with Table 4.4-2 at 40-month intervals fall in Category C-3, the inspection frequency shall be increased to at least once per 20 months. The increase in inspection frequency shall apply until the subsequent inspections satisfy the criteria of

, Specification 4.4.5.3a; the interval may then be extended to a f maximum of once per 40 months; and i c. Additional, unscheduled inservice inspections shall be performed on

! each steam' generator in accordance with the first sample inspection specified in Table 4.4-2 during the shutdown subsequent to any of the following conditions:

1) Reactor-to-secondary tubes leaks (not including leaks originating from tube-to-tube sheet welds) in excess of the limits of -

Specification 3.4.6.2,

2) A seismic occurrence greater than.the Operating Basis Earthquake,

3) A loss-of-coolant accident requiring actuation of the Engineered Safety Features, and

4) A main steam line or feedwater line break.

l McGUIRE - UNITS 1 and 2 3/4 4-13

REACTO'1 COOLANT SYSTEM 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 nominal tube wall thickness, if detectable, may be considered as i

imperfections;

2) Degradation means a service-induced cracking, wastage, wear or i

general corrosion occurring on either inside or outside of a tube; i

3) Degraded Tube means a tube containing imperfections greater than or equal to 20% of the nominal wall thickness caused by degradation; 3

4)  % Degradation means the percentage of the tube wall thickness affected or removed by degradation; 1

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

6) Plugging Limit means the imperfection depth at or beyond which the I

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 tubesheet region below the F* distance.]

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 feedwater 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 i

NOTE 1: The application of F* (the bracketed sentence) expires ninety days following the startup of each Unit following the fifth refueling outage on each respective unit.

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McGUIRE - UNITS 1 and 2 3/4 4-14 i

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 eddy 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.

b. The steam generator shall be determined OPERABLE af ter 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

a. Within 15 days following the completion of each inservice inspection of steam generator tubes, the number of tubes plugged in each steam generator shall be reported to the Commission 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.

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l Amendment No. (Unit 1)

McGuTRE - Uh1Ts i and 2. 3/44-/5 Amendment No. (Unit 2) l l

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REACTOR COOLANT SYSTEM l BASES 3/4.4.4 RELIEF VALVES 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 maintained. The program for inservice inspection of steam generator tubes is based on a modification of Regulatory Guide 1.83, Revision 1. Inservice i 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. 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 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 during normal operation and by postulated accidents. Operating plants have demonstrated that

reactor-to-secondary leakage of 500 gallons per day per steam generator can l readily be detected by radiation monitors of steam generator blowdown. Leakage in j 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 reqvired for all tubes with imperfections in the free span region and i within theF* distance exceeding the plugging limit of 40% of the tube nominal wall l thickness. Steam generator tube inspections of operating plants have demonstrated l the capability to reliably detect degradation that has penetrated 20% of the original tube wall thickness. For tubes with imperfections found greater than two inches below the top of the tubesheet, plugging is not required.

McGUIRE - UNITS I and 2 B 3/4 4-3

ATTACBMENT 2

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ATTACHMENT 3

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