ML18051B077

Proposed Tech Specs Re Steam Generator Augmented Inservice Insp Program Reflecting Results of 1983/1984 Steam Generator Evaluation & Repair Program

ML18051B077
Person / Time
Site:	Palisades
Issue date:	09/28/1984
From:	CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
To:
Shared Package
ML18051B076	List: ML18051B075 ML18051B077
References
NUDOCS 8410020386
Download: ML18051B077 (7)

Text

'.

CONSUMERS:. POWER COMP ANY PALISADES PLANT -

DOCKET* 50..:.255... LICENSE DPR-20

.. PROPOSED TECHlUCAL SPECIFICATIONS CHANGE REQUEST PROPOSED PAGES-I I

• 6 Pages TS0984-0002-NL02

• ~..

4. i4 Augme~ted In.service Inspection Program for Steam Generators.

• Applicability

~Applies to the tubes within both steam generators

• Objective To provide.assurance *of continued integrity of the steam generator tubes over. their serVice lifetime.*

Specification 4.14.1 Inspection InterVal

• Inspectio~s wili be perfomed at* an interval of no more than 30

• calendar months after the *previous inspection *. _Additional tube inspec-

_tions shall be. performed when primary to secondary leakage (not including leaks originating from tube to.tube sheet welds) exceeds the* leakage limits delineated in Section 3._l.5d.

4.14~2 Inspection Requirements 4~14.* 2 *. 1

.. 4.14 ~.2. 2 4.14.2.3

.4.14. 2. 4...

4.14.2.5 For the purposes ~f this specificatio~ *. "tupe" refers

• to *that portion of.the steam generator tubing from the point of entry on the cold bg*side to the top support*of.

the cold leg,* or frotn the point of entry on* the hot leg

• side to the top support of the cold leg.

• Tubes. *requiring inspection will* include* all' unplugged tubes with eddy current indications. of tube* wall degra-*

• elation greater than.or equal to 30% in either of the previous two insp*ections.

• Limited access tubes subject to this requirement, which result in significant added radiation exposure to inspect, shall be' inspected during

. an interval not to 'exceed two consecutive inspections._

Tubes requiring inspection will also i~clude a raridom.

sample of 2% of the hot leg tubes and 1% o.f the cold leg tubes in each steam generator *. Random samples shall be

_*drawn from those unplugged. tubes that do not have tube

• wall degradation identified as. greater than or equal to.

30% during 'the previous two inspections.

A baseline inspeciion of all newly.installed sleeves sh.all be performed prfor to plant operation,.

Inspection of each installed sleeve shall be_performed at*a minimupi frequency* of once per three steaui generator tube

• inspections whose interval is def.ined in Section 4.14.1.

• In the case where a tube is sufficiently restricted :to

• prevent passage of.an*0.540-inch'diameter* probe (blocked),.

all unplugged tubes surrounding the.blocked tube will be

. gauged to ensure acceptable denting levels.*

4-68 PROPOSED TS0984-0001.:.:.NL02

4.14'. 2. 6 In the event that tube inspections. are required* due to. *.

primary to secondary leakage, a> 3% *sample of unplugged tubes in-the affected*leg(s) in each steam generator with leakage in violation of the limits of Section 3d.5d shall

• be inspected.

4.14."3 Inspection Te~hniques 4.14.3.1 4.14.3.2 '

Inspection techniques used shall separately or.in

• combination be* capable of providing results _that serve to fulfill the inspection requirements and to*which the repair criteria can be applied.

In determining that a defect exists at a*given tube location, indications froin several eddy current tests may be averaged during a given inspection.,

However, su.ch averaging shall be based on not less than three eddy.

. current tests.

4.14.4 Supplementary Sampling Requirements 4.14.4.1 If the inspection pursuant to 4.14~2.2 and 4.14.2.3.. or 4.14.2.6 yields results that exceed one or more of the f()llowing, criteria, then. additional samples of unplugged tubes shall be. inspected.according to Figure 4.14.1.

a)

More thari *. 10%. of the inspected tubes in a leg have detect::ibie.wall. degradation (greater than or equal to 30% through wall) where no. previous degradation was

• detecte.d *.

. b)

• More than 10% ot" the inspected ttibes in a leg exhibit.

further wall degradation (greater than a 10% increase in through wall degradation).

c)

• More than 1% of the inspected tubes in a leg have.

indications of tube* wall degradation in excess of.the repair.criteria of Section 4.14.5 where 'no wall degradat.ion greater than *30% was detected in. the previous two inspections.

4. 14. 4. 2 In the event that any of the above* limits are* exceeded,..

prompt-notification to the Nuclear Regulatory CommissiOn pursuant' to 10.CFR 50. 72 shall occur~

4.14.4.3 When applying the criteria of Paragraph 4.14.4*1* to.the.

inspection-sample of Paragraph 4. 14. 2. 6,

• the leaking. tubes

• that initiated the inspectiqn are not* to be reflected in the.sample inspection resuits.

4-68a

. PROPOSED TS0984-0001-NL02

. ~..

4. 14. 4. 4

• • When applying the criteria in Paragraph 4. 14. 4 ~ 1 to the

.tube sample inspection results; the samples are not to be treated cumulatively. The criteria shall*be applied only

• to the inspect.ion r_esults. froin the immediate additional

. *.sample when deciding whether or _not to inspect the next

• additional sample in the progression of.Figure 4.14.1.

4.14. 5 Repair Criteria*

4.14.5.1. A tube shall be declared defective and shall be repaired *

• .using methods consistent with Paragraph 4~ 14. 5. 5 under the

. : following conditions:

4.14.5.2 TS098_4-0001-NL02 a)

Inspection. of the tube produces an eddy current indication of volumetric degradation exceeding the limits as listed in Paragraphs 4.14.5.2 and 4.1.4.5.3.*

b)

Inspection of.the tube identifie* the presence of a crack indication.

c)

Inspection of.the tube produces an eddy current indication of tube wall degradation that is uninter-pretable and was greater than or* equal to 45% during***

. the previous* inspection.*

• d)

Tube restrictions prevent passage of an 6. 540-inch" diameter probe-~

• The following volumetric degradation limits* shall be*

useci to identify defective tubes:

a:)

Indications greater than 51% through wall identified by the 4C4F eddy current* technique or equivalent.

b)

• Indications greater than** 58% *through wall identified by a *bobbin probe eddy current* technique o.r equiv-

• alent. -

c)

Multiple indications greater than 29% through.wall identified by a bobbin probe. eddy current techniqu_e

• or equivalent.*

.4-68b PROPOSED

1.

• . 4.14. 5. 3

• The volumetric degradation limits. for regions in: the

• tube/sleeve assemblies are as follows:

Region The und~formed region* of*the tube/sleeve assembly containing the original. *imperfection requiring ~leeving*.

Degradation Limit Sleeve degr~dation*~*.34~

tube degradation ~x~eeds degradation limit for*an t.insleeved* tube.

• and*

the

2.

The region containing the expansion joint *. Specifically, the region Either sleeve degradation = 25%

when tube degradation in region 1 exceeds the degradation limit for an unsleeved section; *or tube.

degradation in region 2is greater than the degradation limit for an unsleeved tube *.

of the tube/sleeve assembly bounded by lines approximately 1/4 inch and 2 *inches in board f-rom the sleeve

• ends.*

3.

The region of the tube/sleeve assembly containing approximately Tube* *degradation exceeds. the degradation* limits for.an unsleeved tube.

1/4 inch *of each e~d of the assembly.-

4.14.5.4-

• If the mean degradation.increase over the intenrai since the previous steam generator inspection is greater than or equal to 1%, then the Nuelear Regulatory Cotinnission shall

_approve new degradation limi~s.

.4.14~5.5 Plugging each end of a* defective tube is. considered, as accept~ble repair for. all cases. in Paragraph.. 4. 14. 5.1.

However, sleeving may be selected as an alternative repair me_thod *.

Basis*

4!14.6 Reporting Requirements

• A steam generator inspection report shall be submitted to. the

_Nuclear Regulatory Commission within 30 days of completion of the insp_ection and required repairs.,

Guidance for establishing the requirements of this specifiCation is taken from

• Regulatory Guides 1. 83 and 1.121, Combustion Engineering Standard Technical

.. Specifications, and past experience with the Palisades*steam generator problems.

In October 1974, the secondary side water chemistry treatment was changed from

• .. coordinated phosphate treatment to all.volatile treatment in order to arrest the degradatian that had been *obseryed* in the* steam generators *.

• Both intergranular attack and wastage.were present.at the time and appeared to be

_growing.

The steam generators suffered from excess leakage in January 1973, in August_ 1973, and in May 1974.

• Subsequent eddy current examinations between 1974.and.1981 demonstrated.that

.degradation growth had_ceased.

However, minor tube denting began_ to occur as

• • a *result of the switchover to. all_ volatile treatment..

4-68c PROPOSED

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PARAGRAPHS 4.14.2.2 4.14.2.3 PARAGRAPH 4.14.2.6

-FIGURE 4.14.1*- SUPPLEMENTARY SAMPLING.FLOW CHART

.... *INSPECT ADDITIONAL FAIL INSPECT ADDITIONAL 3% SAMPLE IN.

.r 6% SAMPLE IN PASS FAiL

.... AFFECT£µ LEG(S}

AFFECTED LEG,(S),

.. F"ASS

'.. ~-

~Ir PASS FAIL

[

1...

REPAIR

\\

FAIL

' ~

~,

-~ Ir I

INSPECT 3% S.AMPLE

• PASS.

• REPAIR IN REMAINING LEG{S)

ADDITIONAL INSPECTION SAMPLES*IN AF"1"ECT lill

... ~

LEG(S) AS AGREED TO

. BY* THE NRC

.. PASS.

FAIL

• CONSIDER INSPECTION

.....OF 3% SAMPLE IN

... I N.O ACTION I REMAINI,NG LEG(S}

. r. I PASS-. STEAM GENE~TOR LEG(S) PASSl~G THE CRITERIA O~ PARAGRAPH 4.14~4.l FAIL - STEAM GENERATOR LEG(S} *FAILING THE CRITERIA OF PARAGRAPH 4.14.4.1

In.March 1982, a primary to secondary leak in excess o; the technical.speci-fication limit of 0.3 gallons per minute occurred in steam generator 'A'.

Initi-8.1 eddy current e~amination of. possible leakers with the bob.bin.probe showed no new tube defects.

Subseq~ent examinati~ns r,,;ith a pan:*cake type eddy current probe and addi-

. tional* b.obbin probe examinations showed the leaking* defects to be through*

wall witK a circumferential orientation.

At* this pOint, Consumers Power, Companycommitted to develop a pancake probe (4C4F) for use iil the 1983 refueling outage.

The 1983 bobbin coil.inspection confirmed that there was no degradation increase in the steam generators.

However, a 100% inspectioµ of the s~eam

. generators with.the 4C4F probe :*revealed ci. number of circumferential crack indications that had apparently been in existence for some time but had.gone undetected during previous bobbin probe examinations *. In.addition, a number of. intergrannular attack indications that. were not previously recognized

• wer.e also characterized* throughout both gene~ators using the 4C4F probe.

in Section 4.14.1, the inspection interval requirement *has been established at a maximum of to 30 months.. While the intent is to conduct an inspection.

during each scheduled r.efueling outage, the long outage durations experienced at the* Palisades Plant indicate a 30 month rather thaff a.. 24 month interval limit is appropriate to prevent unscheduled.shutdowns for inspection.

The inspection of a 3% sample of.tubes* in steam generator legs exhibiting leakage. is intended to provide inf.ormatiori as to whether or not degradation is increasing~*

• The leaking tube (s). will not be included in the.initi.al *.

inspection sample results.* Inclusion of the leaking* tubes could. *ciistort the inspection results and lead t.o unncessary. inspections. and. personel radiat.ion exposure.* ***. Such tube leakage could be due to* isolated effects rather than

• *general degradation increases.

The supplementary sampling requirements in Section 4. 14.* 4 are intended to provide guidance in determining the app-ropriate action in the event that any of the criteria of Paragraph 4.14.4.l are.exceeded.

These requirements will serve to help clarify the nature and. extent *of additional or.new degradation in the steam generators.

The results of inspection samples are not treated cumulatively because as the nature and extent of the additional or new degradation becomes clearer with the inspection of.more tubes, the criteria-for selecting tubes for* additional samples may change *. Therefore, it is not appropriate to combine*the results of two separate inspection samples when the tube selection criteria differs" between them *.

The volumetric degradation limit for the 4C4F eddy current techn1que is based*

• . upon the findings.Of the qualification. prqgr.am.

Details of the 4C4F tec;hnique.

qualification program are in the 1983/1984 Steam Generator Evaluation and

• Repair Repor.t*,. Docket 50-255, License DPR-20.

• 4-69

• PROPOSED TS0984-0001-NL02 *.