ML20207F290

Proposed Revised Tech Specs Incorporating Combustion Engineering SG Welded Tube Sleeve TR Rev

ML20207F290
Person / Time
Site:	Prairie Island
Issue date:	03/01/1999
From:	NORTHERN STATES POWER CO.
To:
Shared Package
ML20207F275	List: ML20207F271 ML20207F277 ML20207F290
References
NUDOCS 9903110214
Download: ML20207F290 (6)

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• i Exhibit B Prairie Island Nuclear Generating Plant License Amendment Request Dated February 5,1999 Proposed Changes Marked Up On Existing Technical Specification Pages l

Exhibit B consists of existing Technical Specification pages with the proposed changes highlighted on those pages. The pages affected by this License Amendment Request are listed below:

TS.4.12-4 TS.4.12-5 A

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TS.4.12-4 REV 137 8/13/98 D. Accentance Criteria

. '1. As'used in this Specification:

(a) Imoerfection 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 imperfections.

'(b) Degradation means a service-induced cracking, wastage, wear or general corrosion occurring on either inside or outside of a tube.

(c) Deuraded Tube means a tube containing imperfections 220% of the nominal wall thickness caused by degradation.

(d)  % Degradation means the percentage of the tube wall thickness affected or removed by degradation.

(e) Defect means an imperfection of such severity that it exceeds the repair limit. A tube containing a defect is defective.

(f) Egonir Limit means the imperfection depth at or beyond which the tube shall be removed from service by plugging or repaired by sleeving because it may become unserviceable prior to the next inspection and is equal to 50% of the nominal tube wall thickness. If significant general tube thinning occurs, this criteria.will be reduced to 40% wall penetration. This definition does not apply to the portion of the tube in the I

tubesheet below the F* or EF* distance provided the tube is not degraded (i.e., no indications of cracks) within the F* or EF* i distance for F* or EF* tubes. The repair limit for the l pressure boundary region of any sleeve is 3425% of the nominal sleeve wall thickness. This definition does not apply to tube support plate intersections for which the voltage-based repair >

criteria are being applied. Refer to Specification 4.12.D.4 l for the repair limit applicable to these intersections. l l

(g) 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. ,

l (h) Tube Insoection 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.

(i) Sleevinn is the repair of degraded tube regions using a new Alloy 690 tubing sleeve inserted inside the parent tube and sealed at each end by velding or by replacing the lower veld in a full depth tubesheet sleeve with a hard rolled joint. The new sleeve becomes,the pressure boundary spanning the original degraded tube region.

t l t TS.4.12-5 REV 137 8/13/98

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(j) F* Distance is the distance from the bottom of the hardroll j transition toward the bottom of the tubesheet that has been l

. . conservatively determined to be 1.07 inches (not including eddy I current uncertainty). The F* distance applies to roll expanded l regions below the midplane of the tubesheet l l

(k) F* Tube is a tube with degradation, below the F* distance.  !

equal to or greater than 40% and not degraded (i.e., no j indications of cracking) within the F* distance.

(1) EF* Distance is the distance from the bottom of the upper hardroll transition toward the bottom of the tubesheet that has been conservatively determined to be 1.62 inches (not including eddy current uncertainty). EF* distance applies to roll ~

expanded regions when the top of the additional roll expansion is 2.0 inches or greater down from the top of the tubesheet (m) EF* Tube is a tube with degradation, below the EF* distance, equal to or greater than 40%, and not degraded (i.e., no indications of cracking) within the EF* distance.

2. The steam generator shall be determined OPERABLE after completing the corresponding actions (plug or repair by sleeving all tubes exceeding the repair limit and all tubes containing through-wall cracks or  ;

classify as F* or EF* tubes) required by Tables TS.4.12-1 and TS.4.12-2.

3. Tube repair, after Octcher 1, 1007Ab'il15f,Ti999, using Comhustion Engineering welded sleeves shall be in accordance with the methods described in the following:

CEN-629-P, Revision GD3IP, " Repair of Westinghouse Series 44 and 51 ,

Steam Generator Tubes Using Leak Tight Sleeves":

GE"-520-P. f.ddcadu: 1, Rcvicien 1. "Rcpair of Ucctinghoucc Scrico 'd end-51 Ctcan Ccacrator Tubcc "cing Lech Tight Ciccvcc" ,

4. Inbe Suenort Plate Repair Limit is used for the disposition of a j steam generator tube for continued service that is experiencing predominantly axially oriented outside diameter stress corrosion I cracking confined within the thickness of'the tube support plates. l At tube support plate intersections. the repair limit is based on maintaining steam generator serviceability as described below:

a. Steam ger.erator tubes, whose degradation is attributed to outside I diameter stress corrosion cracking within the bounds of the tube j support plate with bobbin voltages less than or equal to 2.0 volts l will be allowed to remain in service.  !

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b. Steam generator tubes, whose degradation is attributed to out. %

diameter stress corrosion cracking within the bounds of the tube support plate with a bobbin voltage greater than 2.0 volts, will be repaired or plugged, except as noted in Specification 4.12.D.4.c below.

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Exhibit C  ;

i Prairie Island Nuclear Generating Plant License Amendment Request Dated February 5,1999 Revised Technical Specification Pages j Exhibit C consists of revised pages for the Prairie Island Nuclear Generating Plant Technical Specifications with the proposed changes incorporated. The revised pages are listed below:

5 TS.4.12-4 TS.4.12-5  ;

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\ . a TS.4.12-4 REV D. Accentance Criteria

. 'I. As'used in this Specification:

(a) Imoerfection 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 imperfections.

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

(c) Dgeraded Tube means a tube containing imperfections 220% of the nominal wall thickness caused by degradation.

(d)  % Degradation means the percentage of the tube wall thickness affected or removed by degradation.

(e) Defect means an imperfection of such severity that it exceeds the repair limit. A tube containing a defect is defective.

(f) Reoair TAmit means the imperfection depth at or beyond which the tube shall be removed from service by plugging or repaired by sleeving because it may become unserviceable prior to the next inspection and is equal to 50% of the nominal tube wall thickness. If significant general tube thinning occurs, this criteria vill be reduced to 40% wall penetration. This definition does not apply to the portion of the tube in the tubesheet below the F* or EF* distance provided the tube is not degraded (i.e., no indications of cracks) within the F* or EF' distance for F' or EF' tubes. The repair limit for the pressure boundary region of any sleeve is 25% of the nominal l sleeve wall thickness. This definition does not apply to tube support plate intersections for which the voltage-based repair criteria are being applied. Refer to Specification 4.12.D.4 for the repair limit applicable to these intersections.

(g) Unserviceable describes the condition of a tube if it leaks or '

contains a defect large enough to affect its structural l

integrity in the event of an Operating Basis Earthquake, a loss-of-coolant accident, or a steam line or feedwater line break. .

(h) Tube Insoection means an inspection s2 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.

(i) Sleeving is the repair of degraded tube regions using a new i Alloy 690 tubing sleeve inserted inside the parent tube and sealed at each end by welding or by replacing the lower veld in .

a full depth tubesheet sleeve with a hard rolled joint. The j new sleeve becomes the pressure boundary spanning the original 1 degraded tube region. j

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• t , TS.4.12-5 i

REV j (j) l 7' Distance is the distance from the bottom of the hardroll i transition toward the bottom of the tubesheet that has been j conservatively determined to be 1.07 inches (not including eddy current uncertainty). The F* distance applies to roll expanded regions below the midplane of the tubesheet (k) F* Tube is a. tube with degradation, belev the F* distance, equal to or greater than 40%, and not degraded (i.e., no indications of cracking) within the F* distance.

(1) EF* Distance is the distance from the bottem of the upper hardroll transition toward the bottom of the tubesheet that has been conservatively. determined to be 1.62 inches (not including eddy current uncertainty). EF* distance applies to roll expanded regions when the top of the additional roll expansion is 2.0 inches or greater down from the top of the tubesheet (m) .EF* Tube is a tube with degradation, below the EF* distance, equal to or greater than 40%, and not degraded (i.e., no l indications of cracking) within the EF* distance.

2. The steam generator shall be determined OPERABLE after completing the corresponding actions (plug or repair by sleeving all tubes exceeding the repair limit and all tubes containing through-wall cracks or l classify as F* or EF* tubes) required by Tables TS.4.12-1 and ',!

TS.4.12-2.

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3. Tube repair, after April 1, 1999, using Combustion Engineering l l velded sleeves shall be in accordance with the methods described in 6 the following:  :

CEN-629-P, Revision 03-P, " Repair of Westinghouse Series 44 and 51 l Steam Generator Tubes Using Leak Tight Sleeves"-  ;

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4. Tube Sunoort Plate Renair Limit is used for the disposition of a -l steam generator tube for continued service that is experiencing predominantly axially oriented outside diameter stress corrosion cracking confined within the thickness of the tube support plates.

At tube support plate intersections, the repair limit is based on maintaining steam generator serviceability as described below:

a. Steam generator tubes, whose degradation is attributed to outside diameter stress corrosion cracking within the bounds of the tube support plate with bobbin voltages less than or equal to 2.0 volts will be allowed to remain in service.

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b. Steam generator tubes, whose degradation is attributed to outside  :

diameter stress corrosion cracking within the bounds of the tube  ;

support plate with a bobbin voltage greater than 2.0 volts, will be I repaired or plugged. except as noted in Specification 4.12.D.4.c ,

below. 1 l

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