ML20209G196

Proposed Tech Specs,Incorporating Ref to C-E Sleeving Methodology for RCS Steam Generator Tubes

ML20209G196
Person / Time
Site:	Zion  File:ZionSolutions icon.png
Issue date:	09/02/1986
From:	COMMONWEALTH EDISON CO.
To:
Shared Package
ML20209G015	List: ML20209G010 ML20209G196
References
1588K, 2055K, NUDOCS 8609120389
Download: ML20209G196 (14)

Text

ATTAO9 BIT 1 PROPOSED ZION APPENDIX A TECHNICAL SPECIPICATION CHANGES TO SECTION 4.3 REACTOR COOLANT SYSTEM Pages Modified: 74 74a 74b 74e 74f 74g 74h 74j 78a Pages Added: 74 fl l

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IIMIIING COND1110N FOR OPERA 110N SURVLILL ANCE REQUIREMENI 3.3.1.8 Steam Generators 4.3.1.B Steam Generators

1. All steam generators shall be OPERABLE Each steam generator shall be demonstrated as defined in Section 4.3.1.B. OPERABLE by performance of the following augumented inservice inspection program and Al[lICABilllY:

j Modes 1, 2, 3, and 4 the requirements of Specification 4.3.4.

ACTION: With one or more steam generators 1. Steam Generator Samp_le Selection and inoperable, restore the inoperable inspection generator (s) to OPERABLE status prior to increasing lavg above 200*F. Each steam generator shall be determined OPERABLE during shutdown by selecting and inspecting at least the minimum number of steam generators specified in Iable 4.3.B-1.

2. Steam Generator Tube Sample Selection and insRection The steam generator tube minimum sample size, inspection result classification, and the corresponding action required shall be as specified in Table 4.3.B-2.

The inservice inspection of steam generator tubes shall be performed at the frequencies specified in Specification 4.3.1.B.3 and the inspected tubes shall be verified acceptable per the acceptance criteria of Specification 4.3.1.B.4. The tubes selected for each inspection shall include at least 3% of the total number of tubes in all steam generators. When applying the exceptions of 4.3.1.B.2.a through 4.3.1.B.2.c, previous defects or imperfections in the area repaired by sleeving are not considered an area requiring reinspection. The tubes selected for these inspections shall be selected on a random basis except:

10500/10510 74 a

1.lHillNG CONDil10N IOR OPERAllHN SURVEll.EANCE REQUIREMEN1 4.3.1.B.2

a. Where experience in similar plants with similar water chemistry indicates critical areas to be inspected, then at least 50% of the tubes inspected shall be from these critical areas.

) b. 1he first sample inspection during each j inservice inspection (subsequent to the preservice inspection) of each steam generator shall include:

1. All nonplugged tubes that previously had detectable wall penetrations (> 20%) and

2. Tubes in those areas where experier.ce has indicated potential problems.

c. The second and third sample inspections during each inservice inspection may be less than a full tube inspection by concentrating the inspection on those areas of the tube sheet

, array and on those portions of the tubes where tubes with imperfections were previously found.

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d. The tube inspection shall be conducted according to 4.3.1.B.4.A.8. Sleeve

. inspections, where applicable, shall be 2 conducted according to 4.3.1.B.4.A.9. If a tube does not permit the passage of the eddy current inspection probe the entire length and through the U-bend; this shall be recorded and an adjacent tube shall be inspected. The tube which did not allow passage of the eddy current probe shall be considered degraded.

10500/10510 74a

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! LIM 111NG COND1110N FOR OPERAllHN SURVLILLANCE REQUIREMLN1 4.3.1.B.2 (Continued)

e. The tube inspections will include at least 3%

of the total number of sleeved tubes in all 4 steam generators or all of the sleeved tubes in the generator chosen for the inspection program, whichever is less. These inspections will include both the tube and the sleeve.

1he results of each sample inspection shall be classified into one of the following three categories:

Catggory 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, nut 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.

N01E: In all inspections, previously degraded tubes must exhibit significant (> 10%) further wall Amendment Nos. 34 & 31 dated 2/6/78 penetrations to be included in the above percentage calculations.

4.3.1.B.3 In_spgction Frequencies The above required inservice inspections of steam generator tubes shall be 10500/10510 74b performed at the following frequencies:

IIHillNG CONilll10N FOR OPERA 110N SURVLill ANCE REQUIREMENI

1. Imperfection means an exception to the dimensions, finish or contour of a tube from that required by f abrication drawings or specifications. Eddy-current testing indications below 20% of the nominal tube wall thickness, if detectable, may be considered as imperfections.

2. Oggradation 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 > 20% of the nominal wall thickness caused by degradation.

4.  % Degradation means the percentage of the tube wall thickness affected or removed by degradation.

S'. Ogfgct means an imperfection of such severity that it exceeds the Plugging or Repair Limit. A tube containing a defect is defective.

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09180/09190 74e

LIMillNG CONDil10N FOR OPERA 110N SURVEILLANCE REQUIREMEN) ,

6. Plugging or Repair Limit means the imperfection depth at or beyond which the tube shall be repaired (ie. sleeving) or removed from service by plugging because it may become unserviceable prior to the next inspection and is 2 40% of the nominal tube wall thickness. Plugging Limit for sleeves means:

a. for the area in the upper weld. joint, any imperfection produced by degradation shall be plugged unless it can be clearly demonstrated by a qualified NDE technique that the imperfection is < 33% of the nominal wall thickness;

b. for the area below the upper weld joint any imperfection 2 33% of the nominal sleeve thickness shall be plugged;

c. for the area of the tube behind the sleeve and above the upper weld joint, any imperfection produced by degradation shall be plugged unless it can be clearly demonstrated by a qualified NDE technique that the imperfection is < 40% of the nominal wall thickness.

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 f eedwater line break as specified in 4.3.1.B.3.C above.

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l.lHillNG CONDil10N FOR OPERA 110N SURVEILLANCE REQUIREMENT B. The steam generator shall be determined OPLRABl.L after completing the corresponding action (plug or repair all tubes exceeding plug or repair limit and all tubes containing through-wall cracks) required by Table 4.3.B-2.

4.3.1.B.5 Reports A. Following each inservice inspection of steam generator tubes, the number of tubes repaired or plugged in each steam generator shall be reported to the Commission within 15 days.

B. The completed results of the steam generator tube inservice inspection shall be included in the SPECIAL REPORI pursuant to Specification 6.6.3.(c). lhe SPECIAL REPORI shall be submitted within 12 months following completion of the inspection. lhis report shall include:

1. Number and extent of tubes inspected.

2. l.ocation and percent of wall thickness penetration for each indication of an imperfection.

3. Identification of tubes repaired or plugged.

09100/09190 74g

1.lMillNG LONDillON FOR OPERA 110N SURVLILLANCE REQUIREMEN1 h

C. Results of steam generator tube  ;

inspections which fall in to category C-3 and require prompt notification of the Consnission shall be reported

- pursuant to Specification 6.6.2 prior .

to resumption of plant operation. The  !

l written follow up of this report shall

.i i provide a description of investigation

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the tube degradation and corrective i measures taken to prevent recurrence.

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l ABI E 4.3.B -2 SIEAM GENERA 10R luBL INSPEC110N ISI SAMPil liiSPECl10N 2ND SAMPLE INSPECil0N 3RD SAMPLE INSPEC110N

._ C -2 Plug or repair _ _ _ _ _ _ _ _ _ _ _ _ _ _ C2 Plug or repair C-2 Plug or repair defective tubes and defectives tubes and + defective tubes inspect additional 2S h inspect additional 45 tubes in this S.G. tubes in this S.G. -

If C-3 Inspect all tubes in k C -3 Perform action for C-3

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C-3 Perform action for C-3 this S.G. plug or M result of first sample result of first sample repair defective tubes and inspect 2S tubes in each other S.G. j L bd*PI ' '#'

All other S.G.'s None A minimum of Prompt notification to are C-1 S. lubes per NRC pursuant to S.G. Specificalion 6.6.2 Same S.G.'s C-2 Perform action for but no additional C-2 result of S.G. are C-3 second sample II 4L Additional S.G. Inspect all tubes is C-3 in each S.G. and ~~

plug or repair defective tubes.

Prompt notification to NRC pursuant to specification 6.6.2 S-3_N.% Where N is the number of steam generators in the unit and n is the number of steam generators n inspected during an inspection 74j 091h0/09190

Bases:

3.3.1 Steam Generators L

4.3.1 1he Surveillance Requirernents for inspection of primary- to-secondary leakage less than this limit the steam generator tubes ensisre that the during operation will have an adequate margin of structural integrity of this por tion of the RCS safety to withstand the loads imposed during normal will be maintained. lhe prograni for inservice operation and by postulated accidents. Operating inspection for steam generator tubes is based on plants have demonstrated that primary-to-secondary d modiflCation or Regulatory Guide 1.83, leakage of 500 gations per day per steam generators Revision 1. Inservice inspection of steam can readily be detected by radiation monitors of generator tubing is essential in order to steam generator blowdown. Leakage in excess of this nutntain surveillance of the conditions of the limit will require plant shutdown and an unscheduled tunes in the event that there is evidence of inspection, during which the leaking tubes will be mecharitcal damage or progressive degradation due located and plugged.

to design, manufacturing errors, or inservice conditions that lead to corrosion. Inservice Wastage-type defects are unlikely with proper inspection of steam generator tubing also chemistry treatment of the secondary coolant.

provides a mearis of characterizing the nature flowever, even if a defect should develop in service, and cause of any tube degradation so that it will be found during scheduled inservice steam corrective measures _can be taken. generator tube examination. Plugging or repairs will be required for all tubes with imperfections lhe plant is expected to be operated in a manner exceeding the > 40% limit of the tube nominal wall such that the secondary coolant will be thickness. Steam generator tube inspections of maintained within those chemistry limits found operating plants have demonstrated the capability to to result in negligible corrosion of the steam reliably detect degradation that has penetrated 20%

generator tubes. If the secondary coolant of the original tube wall thickness.

chemistry is not maintained within these limits, localized corrosion may likely result in stress Whenever the results of any steam generator tubing corrosion cracking. lhe extent of cracking inservice inspection fall into Category C-3, these during plant operation would be limited by the results will be promptly reported to the Commission limitation of steam generator tube leakage pursuant to Specification 6.6.2 prior to resumption between the primary coolant system and the of plant operation. Such cases will be considered by secondary coolant system (primary-to-secondary the Commission on a case-by-case basis and may result leakage 500 gallons per day per steam in a requirement for analysis, laboratory generator). Cracks having a examinations, tests, additional eddy-current inspection, and revision of the lechnical Specifications, if necessary.

78a 09100/09190

ATTACHMENT 2 EVALUATION OF SIGNIFICANT HAZARDS CONSIDERATION PROPOSED CHANGES TO ZION TECHNICAL SPECIFICATION APPENDIX A - SECTION 4.3 REACTOR COOLANT SYSTEM DESCRIPTION OF AMENDMENT REOUEST An amendment to the Zion Facility Operating License is proposed to allow the use of an NRC approved sleeving process to repair defective steam generator tubes.

BACKGROUND 10 CPR 50.92 states that a proposed amendment will involve a no significant hazards consideration if the proposed amendment does not:

(1) Involve a significant increase in the probability or consequences of an accident previously evaluated; or (2) Create the possibility of a new or different kind of accident from any accident previously evaluated; or (3) Involve a significant reduction in a margin of safety.

In addition, the Commission has provided guidance in the practical applica-tion of these criteria by publishing eight examples in 48 FR 14870.

The discussion below addresses each of these three criteria and demonstrates that the proposed amendment involves a no significant hazards consideration.

BASIS FOR NO SIGNIFICANT HAZARDS CONSIDERATION DETERMINATION Does the proposed amendment (1) Involve a significant increase in the probability or consequences of an accident previously evaluated; or (2) Create the possibility of a new or different kind of accident from any accident previously evaluated; or (3) Involve a significant reduction in a margin of safety?

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1 DISCUSSION - ITEM #1 The creation of the option to utilize the Combustion Engineering sleeving process to repair a defective steam generator tubo has no effect on either the probability or consequences of any accident previously evaluated.

The integrity of the steam generator tubes will be equivalent to that of an original tube. The continued integrity of the sleeves will be verified by the inspection program required as a result of this change. Thus, since the structural integrity of the tubes will not be affected by this change, there is no increase in the probability of any accident previously evaluated.

In addition, the steam generator will remain capable of performing its required heat transfer function. The act of placing a sleeve in the steam generator tube actually results in a more efficient steam generator relative to plugging the affected tubes. Thus, the consequences of any accident previously evaluated is unaffected because the heat transfer capability of the steam generators will not be significantly altered.

DISCUSSION - ITEM #2 As discussed above, both the structural integrity and the heat transfer capability of Zion steam generators will not be significantly 1 affected by the use of the Combustion Engineering sleeving process. In addition, the steam generator tube sleeves do not interact with any of Zion's systems. Thus, there is no potential for a new or different kind of accident due to the use of a sleeving process to repair Zion steam generators.

DISCUSSION - ITEM #3 The heat transfer capabilities of Zion steam generators will be improved by utilizing the sleeving process rather than the currently required plugging. The sleeving process will allow a repaired steam generator tube to remain in service, rather than completely blocking the tube's flow with plugs. Since the structural integrity of the steam generators will be unaltered, the net effect of utilizing a steam generator tube sleeving process rather than the currently required plugging procedure will be an increase in the margin of safety. This increase is due to the relatively improved heat transfer characteristics of the steam generator.

It should be noted that the proposed Technical Specifications Thus, represent new controls governing the repair of steam generator tubes.

, example (ii) is applicable to the proposed change.

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Example (ii) reads as follows:

(ii) A change that constitutes an additional limitation, restriction, or control r.ot presently included in the technical specifications: for example, a more stringent survei11ance requirement. ~

Therefore, since the application for amendment satisfies the criteria specified in 10 CFR 50.92 and is similar to examples for which no significant hazards consideration exists, Commonwealth Edison Company has made a determination.that the application involves no significant hazards consideration.

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