ML20077N068

Proposed Tech Specs 4.12 Re Steam Generator Surveillance

ML20077N068
Person / Time
Site:	Prairie Island
Issue date:	01/09/1995
From:	NORTHERN STATES POWER CO.
To:
Shared Package
ML19311B656	List: ML20077N057 ML20077N066 ML20077N068 ML20077N073
References
NUDOCS 9501130286
Download: ML20077N068 (10)

Text

. . . . . . . . . = . . - - - . .- - . _ . . . _ -

I L

Exhibit B j

, t Prairie Island Nuclear Generating Plant j i I

License Amendment Request Dated January 9,.1995  !

I Proposed Changes Marked Up.

On Existing Technical Specification Pages i

. Exhibit B consists of existing Technical Specification pages with the proposed .

changes highlighted on those pages. .The pages-affected by this License, l 4

Amendment Request are listed below i

TS.4.12-2 TS.4.12-4

TS.4.12-5

B.4.12-2 1

1 I

T l

' -~

g130286 950109 e!

DR ADOCK 05000292 p  !

P 4

_ , . , _ <.. ,, , __,~m . ,

TS.4.12-2 REV 76 10/11/95

2. The first sample of tubes selected for each in-service inspec-tion (subsequent to the preservice inspection) of each steam generator shall include:

1 (a) All tubes that previously had detectable wall penetrations

(>20%) that have not been plugged or sleeve repaired in the affected area.

1 (b) Nbes in those areas where experience has indicated j poeential problems.

(c) A tube inspection (pursuant to Specification 4.12.D.1.(h))

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

l 31 ?InVaddi tion stR the';? sample Trc qdired fin? Spec ifica tionW12 ;312 M "

l thr6dghtsk alls tubes twhishj havej had i tije t FhorlL*?britieria appliedleill be)inspectedlinfthetF*tandjL*(regions?of Ltheiroll expand 4d%egiorU JThej rollsexp'anded@egionfoff thssejtubesfmahbe' i ex clude d if r.omitheje'quireme nts i o f%p12. B ; 2 ; a; .

i 4' . The tubes selected as the second and third samples (if required by Table TS.4.12-1) during each inservice inspection may be subjected to a partial tube inspection provided:

(a) The tubes selected for these samples include the tubes from those areas of the tube sheet array where tubes with imperfections were previously found.

(b) 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 i 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%

l of the total tubes inspected are degraded tubes.

I i

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

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

l l

l

TS.4'12-4 REV 76 10/11/95 D. Acceptance Criteria

1. 'As used in this Specification:

(a) Imocrfection means an exception to the dimensions, finish or contour of a tube from that required by fabrication drawings or specifications. Eddy-current testing indica-tions 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)- Degraded 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) Repair 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. Thisfdefinitionydoss otSapply$olths thditubeTin'Tthe0tubesheetibelowf the@iF*loriL*1di'stinc[p6rt-id,. elpfeh thej tubedis fn'o t$hegrddedi (INf.dhoiinhih%$1dris[o fielrabkA th$(F*Mistance)for(F*NhbEs*Addyithihfth(L*3thitiancs][)$Ultad fpKbl*

tubes?

(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 i break.

(h) Tube Inspection means an inspection of the steam generator j tube from the point of entry (hot leg side) completely i around the U-bend to the top support of the cold leg.

(1) Sleeving means that tube sleeving is permitted only in areas where the sleeve spans the tubesheet area and whose' lower joint I is at the primary fluid tubesheet face.

I

'(j )R F* t Di s t'aric e " i si theidi~s tance3 fromi theT bo t tonU b f { thsiliardroll transition? Eowafd Nhslbott6A?offhhedubesheenhdhl[has$een d.onserystikelpjdeterm'ned[hb[bh[1j0$1hches[(h6tynd10S16p,isddi i l current? uncertainty)y i (k)] { F*' Tubeilsfa'?tabsisithydegradatiorGb'sibwiths?F*/ dis tsnceMegaal i' to.:;or? greaseEthari(40%Dandinotidigradeds(' Gif~

~

i

~ " ~ ~

nof~ihdicati6ns^ ' ' ^

~ '

o ficia cking)$1thih3hej F*l; dis;t anc e {

I

TS.6.12-5

'REV 76 10/11/95 (1)'* L*~ Jistance is the distance ^ from the bottom of'the hardroll transition toward the bottom of the tubesheet that has been conservatively, determined to,be 0.5_ inches ,(not, including eddy current uncertainty),lj

(m)J L* Tube" is 'a^ tube'which' has' at' least

1'.34' inch "(ples", eddy current uncertainty) of sound expanded tube below the bottom'of '

the roll transition with no, me're than two bands of axial' (30' degrees ory less fron' tube axis) degradation separating thel sound portions and with sound' tube ,in the, first 0.L inch 'fros;the bottom ofs the roll transition, L* tubes .willt be inspected with s

the rotating pancake' coll; system,(or equivalent technology) in the top two inches of the roll , expanded region to adequately j characterize the, degradation ( A maximum of 600, tube'enda per steam generator may uss, L*. J s When there is 'no degradation in the uppermost'1.07 inches (plus NDE uncertainty) below the' battom 6f the roll stransition, the F* ' criterion appliestand the; tube ,end would not,be counted in the, 600ftube limit y

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 cracksior[cl~assifQs[FQrjg.gtub6s') required by Table TS.4.12-1.

E. Reports

1. Following each in-service inspection of steam generator' tubes,-

if there are any tubes requiring plugging or sleeving, the number of tubes plugged or sleeved in'each steam generator shall be reported to the' Commission within 15 days.

2. The results of steam generator. tube inservice inspections shall be included with the summary reports of ASME Codo j Section XI inspections submitted within 90 days of the"end  !

of each refueling outage. Results of steam generator tube .j i

inservice inspections not associated with a refueling outage  !

shall be submitted within 90 days of the completion of the i inspection. These reports 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 or sleeved.

3. Results of steam generator tube inspections which fall into

Category C-3 require. notification to the Commission prior to i

! resumption of plant operation, and reporting as a special' '

l report to the Commission within 30 days. This special report i shall provide a description of investigations conducted to determine cause of the tube degradation and corrective measures taken to prevent recurrence.

,47 ^ The results of inspections performed under Specification'4}12.B'for all tubes that have defects below the F* or L* distance and r ,we r,e, not plugged,'shall be reported to the Commission within 15, days following the insp,ection. The, report shall, include;

.ls jIdentifIEstleisib f'[F*fand f.L%thbeMand 2 $IMajion {addJespehtqo ff degradatilon]

l-i JB.4.12-2' REV 91 10/27/89-

! 4.12 STEAM GENERATOR TUBE-SURVEILLANCE t l f

l Bases continued plants have demonstrated the capebility to. reliably detect wastage type  :

defects that have penetrated 20% of the original'0.050-inch wall t thickness (Reference-2).

i PluksiW6EjsleefiM[iijsstgequifs@f66)ubeilmist;ig[s1thsigthelF*26) ,

L*[ criteria?

i Whenever the results of any steam ' generator / tubing in-service ' inspection fall into Category C-3,~these results will be promptly reported to the Commission prior to resumption.of plant operation. Such cases will.be considered by the Commission on a case-by-case basis and may result'in t a requirement for analysis,;1aboratory examinations, tests, additional eddy-current inspection, and. revision of'the Technical Specifications,c +

if necessary.

Degraded steam generator tubes may be ' repaired by the installation of l sleeves which span the section of degraded steam generator tubing. A  ;

steam generator tube with a sleeve installed meets the structural  ;

requirements of tubes which are not' degraded' l The following sleeve designs have been found acceptable by the NRC-Staff: ,

i l a. Westinghouse Mechanical SleevesL(WCAP 10757) j

b. Westinghouse Brazed Sleeves ~(WCAP-10820)  ;

I f c. Combustion Engineering Leak Tight Sleeves (CEN-294-P)

Descriptions of other future sleeve designs shall be submitted to the NRC for review and approval prior to their use in the repair of degraded steam generator tubes. The submittals related-to'other sleeve designs ,

shall be made at least 90 days prior to use.

t

)

l l

l J l

l References

1. Testimony of J Knight in the Prairie Island Public Hearing on 1/28/75

2. Testimony of L Frank in the Prairie Island Public Hearing on 1/28/75

l Exhibit C l

Prairie Island Nuclear Generating Plant License Amendment Request Dated January 9,1995

, Revised Technical Specification Pages l

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:

TS.4.12-2 l

TS.4.12-4 TS.4.12-5 B.4.12-2 l

1 l

l l

TS.4.12-2 REV

2. The first sample of tubes selected for each-in-service inspec-tion (subsequent to the preservice inspection) of each steam generator shall include:

(a) All tubes that previously had detectable wall penetrations

(>20%) that have not been plugged or sleeve repaired in the affected area.

(b) Tubes in those areas where experience has indicated potential problems.

(c) A tube inspection (pursuant to Specification 4.12.D.1.(h))

shall be performed on each selected tube. If any selected tube does not permit the passage of the eddypcurrent probe for a tube inspection, this shall be recorded and an adjacent tube shall be selected and subjected to a tube inspection.

3. In addition to the sample required in Specification 4.12.B.2.a through c, all tubes which have had the F* or L* criteria applied will be inspected in the F* and L* regions of the roll expanded region. The roll expanded region of these tubes may be excluded from the requirements of 4.12.B.2.a.

4. The tubes selected as the second and third samples (if required by Table TS.4.12-1) during each inservice inspection may be subjected to a partial tube inspection provided:

(a) The tubes selected for these samples include the tubes from those areas of the tube sheet array where tubes with imperfections were previously found.

(b) 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 that 1% of the inspected tubes are defective.

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

TS.4.12-6 REV D. Acceptance Criteria

1. As used in this Specification:

(a) Imperfection means an exception to the dimensions, finish or contour of a tube from that required by fabrication drawings or specifications. Eddy-current testing indica-tions 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) Degraded Tube means a tube containing imperfections 220%

of the nominal wall thickness caused by de5radation.

(d) % Deeradation 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) Repair 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 tubesheet below the F* or L* distance provided the tube is not degraded (i.e., no indications of cracks) within the F* distance for F* tubes and within the L* distance for L*

tubes.

(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.

(h) 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.

(i) Sleevinz means that tube sleeving is permitted only in areas where the sleeve spans the tubesheet area and whose lower joint is at the primary fluid tubesheet face.

(j ) F* Distance is the distance from the bottom of the hardroll transition toward the bottom of the tubesheet that has been conservatively determined to be 1.07 inches (not including eddy current uncertainty).

(k) F* Tube is a tube with degradation, below the F* distance, equal to or greater than 40%, and not degraded (i.e., no indications of cracking) within the F* distance.

TS.4.12-5

. REV i i

l (1) L* Distance is the distance from the bottom of the hardroll l transition toward the bottom of the tubesheet that has been i conservatively determined to be 0.5 inches (not including eddy  !

current uncertainty).

(m) 1* Tube is a tube which has at least 1.34 inch (plus eddy current uncertainty) of sound expanded tube below the bottom of the roll transition with no more than two bands of axial (30 degrees or less from tube axis) degradation separating the sound i portions and with sound tube in the first 0.5 inch from the l

bottom of the roll transition. L* tubes will be inspected with the rotating pancake coil system (or equivalent technology) in l the top two inches of the roll expanded region to adequately characterize the degradation. A maximum of 600 tube ends per steam generator may use L*. . When there is no degradation in the uppermost 1.07 inches (plus NDE uncectainty) below the bottom of the roll transition, the F* criterion applies and the tube end would not be counted in the 600 tube limit.

2. The steam generator shall be determined OPERABLE af ter 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 L* tubes) required by Table TS.4.12-1. l l

E. Reports l

1. Following each in-service inspection of steam generator tubes, if there are any tubes requiring plugging or sleeving, the i number of tubes plugged or sleeved in each steam generator shall be reported to the Commission within 15 days. ,

1 l

2. The results of steam generator tube inservice inspections l shall be included with the summary reports of ASME Code ,

Section XI inspections submitted within 90 days of the end l of each refueling outage. Results of steam generator tube I inservice inspections not associated with a refueling outage shall be submitted within 90 days of the completion of the inspection. These reports 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 or sleeved.

l

3. Results of steam generator tube inspections which fall into Category C-3 requfre notification to the Commission prior to i resumption 'or plant operation, and reporting as a special j l report to the Commission within 30 days. This special report shall provide a description of investigations conducted to

determine cause of the tube degradation and corrective measures

! taken to prevent recurrence.

4. The results of inspections performed under Specification 4.12.3 for l

all tubes that have defects below the F* or L* distance, and were

! not plugged, shall be reported to the Commission within 15 days following the inspection. The report shall include:

i

1. Identification of F* and L* tubes, and l

2. Location and extent of degradation.

B.4.12-2 REV 4.12 STEAM GENERATOR TUBE SURVEILLANCE Bases continued

! plants have demoastrated the capability to reliably detect wastage type defects that have penetrated 20% of the original 0.050-inch wall thickness (Reference 2).

Plugging or sleeving is not required for tubes meeting either the F* or L* criteria.

Whenever the results of any steam generator tubing in-service inspection fall into Category C-3, these results wf'i be promptly reported to the Commission prior to resumption of plant ,eration. Such cases will be considered by the Commission on a case-by-case basis and may result in a requirement for analysis, laboratory examinations, tests, additional eddy-current inspection, and revision of the Technical Specifications, if necessary.

Degraded steam generator tubes may be repaired by the installation of sleeves which span the section of degraded steam generator tubing. A steam generator tube with a sleeve installed meets the structural requirements of tubes which are not degraded.

The following sleeve designs have been found acceptable by the NRC Staff;

a. Westinghouse Mechanical Sleeves (WCAP 10757)

b. Westinghouse Brazed Sleeves (WCAP-10820)

c. Combustion Engineering Leak Tight Sleeves (CEN-294-P)

Descriptions of other future sleeve designs shall be submitted to the NRC for review and approval prior to their use in the repair of degraded steam generator tubes. The submittals related to other sleeve designs shall be made at least 90 days prior to use.

References

1. Testimony of J Knight in the Prairie Island Public Hearing on 1/28/75

2. Testimony of L Frank in the Prairie Island Public Hearing on 1/28/75