ML18052B312

Proposed Tech Specs,Replacing Previously Proposed Page Changes

ML18052B312
Person / Time
Site:	Palisades
Issue date:	09/15/1987
From:	CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
To:
Shared Package
ML18052B311	List: ML18052B310 ML18052B312
References
NUDOCS 8709210376
Download: ML18052B312 (7)

Text

ATTACHMENT Consumers Power Company Palisades Plant Docket 50-255 PROPOSED TECHNICAL SPECIFICATION PAGE CHANGES September 15, 1987 8709210376- 870915 . ,..,-:

PDR ADOCK 0500025.5*, 11 p -_ *PDR - (.....J 6 Pages TSP0987-0145-NL04

4.14 Augmented Inservice 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 Inspections will be performed at an interval of up to 24 calendar months after the previous inspection.* Additional tube inspections shall be performed when primary to secondary leakage (not including leaks originating from tube to tube sheet welds) exceeds the leakage limits delineated in Specification 3.1.Sd.

4.14.2 Inspection Requirements 4.14.2.1 For the purposes of this specification, "tube" refers to that portion of -the steam generator tubing from the point of entry on the cold leg side to the top support of the cold leg, or from the point of entry on the hot leg side to the top support of the cold leg.

4.14.2.2 Tubes requiring inspection will include all unplugged tubes with eddy current indications of tube wall degradation greater than or equal to 30% in either of the previous two in_spections. .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.

4.14.2.3 Tubes requiring inspection will also include a random sample of 2%

of the hot leg tubes and 1% of 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.

4.14.2.4 A baseline inspection of all newly installed sleeves shall be performed prior to plant operation. Inspection of each installed sleeve shall be performed at a minimum frequency of once per three

• steam generator tube inspections whose intervai is defined in Specification 4.14.1. In the event of sleeve degradation the sleeve inspection interval shall be reevaluated.

• The interval may be extended to 30 months if the mean degradation increase for the previous steam generator inspection interval was less than +1%.

4-68 Proposed TSP0987-0145-NL04

4.14.2.5 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.

4.14.2.6 In the event that tube inspections are required due to primary to secondary leakage, a 6% sample of unplugged tubes in the affected leg(s) in each steam generator with leakage in violation of the limits of Specification 3.l.5d shall be inspected.

4.14.3 Supplementary Sampling Requirements 4.14.3.l 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 following criteria, then additional samples of unplugged tubes shall be inspected according to Figure 4.14.1.

a) More than 10% of the inspected tubes in a leg have detectable wall d~gradation (great.er than or equal to 30% through wall) where no previous degradation was detected.

b) More than 10% of the inspected tubes 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 Specification 4.14.4 where no wall degradation greater than 30%

was detected in the previous two inspections.

4.14.3.2 In the event that any of the above limits. are exceeded, prompt notification to the Nuclear Regulatory Commission pursuant to 10 CFR 50.i2 shall occur.

4-68a Proposed TSP0987-0145-NL04

4.14.3.3

• When applying the criteria of Specification 4.14.3.1 to the inspection sample of Specification 4.14.2.6, the.leaking tubes that inifiat;e*d the* inspection are not to be reflected in the sample inspection results.

4.14.3.4 When applying the criteria of Specification 4.14.3.1 to the tube sample inspection. results, the samples are not to be treated cumulatively. The criteria shall be applied only to the inspection results from the immediate additional sample when deciding whether or not to inspect the next additional sample in the progression of Figure 4. 14 .1.

4.14.4 Repair Criteria 4.14.4.1. A tube shall be declared defective and shall.be repaired using methods consistent with Specification 4.14.4.5 under the following conditions:

a) Inspection of the tube produces an eddy current indication of volumetric degradation exceeding the limits as listed in Specifications 4.14.4.2 and 4.14.4.3.

b) . Inspection of the tube identifies the presence of a crack indication.

c) Inspection of the tube produces an eddy current indication of tube wall degradation that is uninterpretable and was greater than or ~qual to 45% during the previous inspection.

d) Tube restrictions prevent passage of an 0 *. 540-inch diameter probe.

4.14.4.2 The following volumetric degradation limits shall be used 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 or equivalent.

c) Multiple indications greater than 29% through wall identified by a bobbin probe eddy current technique or equivalent.

4-68b Proposed TSP0987-0145-NL04

4.14.4.3 The volumetric degradation limits for regions in the tube/sleeve assemblies are as follows:

Region

• Degradation Limit

1. The undeformed region of the Sleeve degradation > 28% and tube/sleeve assembly containing tube degradation exceeds the the original imperfection degradation limit for an requiring sleeving. unsleeved tube.

2. The region containing the expansion Either sleeve degradation > 19%

joint. Specifically, the region when tube degradation in region 1 of the tube/sleeve assembly bounded exceeds the degradation limit for by lines approximately 1/4 inch and an unsleeved section; or tube 2 inches in board from the sleeve degradation in region r-is.

ends. greater than the degradation limit for an unsleeved tube.

3. The region of the tube/sleeve Tube degradation exceeds the assembly containing approximately degradation limits for an 1/4 inch of each end of the assembly. unsleeved tube.

4.14.4.4 If the mean degradation increase over the interval since the previous steam generator inspection is greater than or equal to 1%,

then new degradation limits shall be submitted to the NRC* for review and approval prior to plant restart.

4.14.4.5 Plugging each end of a defective tube is considered as acceptable repair for all cases in Specification 4.14.4.1. However, sleeving may be selected as an alternative repair method. NRC approval for the sleeving method is necessary prior to repairing.

4.14.5 Reporting Requirements A steam generator inspection report shall be submitted to the Nuclear Regulatory Commission within 30 days of completion of the inspection ~nd required repairs.

Basis 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.

,1 In October 1974, the secondary side water chemistry treatment was changed from coordinated phosphate treatment to all volatile treatment in order to arrest the degradation that ha.d been observed 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.

4-68c Proposed TSP0987-0145-NL04

H U> FIGURE 4.14.1 - SUPPLEMENTARY SAMPLING FLOW CHART "d

0

\0 CX>

I 0

~

...... INSPECT ADDITIONAL FAIL ... INSPECT ADDITIONAL

.... 12% SAMPLES IN 6% SAMPLE IN lJ1 I

l

...... AFFECTED LEG(S)

PASS AFFECTED LEG(S) I 0

~

SPECIFICATIONS FAIL .

4.14.2.2 PASS 4* ~,

PASS FAIL 4.14.2.3 FAIL I REPAIR ,..

4 ...

1....

H ~ , e*

REPAIR

~ . I INSPECT 6% SAMPLE IN REMAINING LEG(S) 4*

PASS ADDITIONAL INSPECTION SAMPLES IN AFFECTED LEG(S) AS AGREED TO I

BY THE NRC PASS SPECIFICATION FAIL 4.14.2.6 P"

CONSIDER INSPECTION OF 6% SAMPLE IN ~NO ACTION I REMAINING LEG(S)

"d PASS - STEAM GENERATOR LEG(S) PASSING THE CRITERIA OF SPECIFICATION 4.14.3.1 11 0 FAIL - STEAM GENERATOR LEG(S) FAILING THE CRITERIA OF SPECIFICATION 4.14.3.1 "Cl*

0 QI ID

~

Basis (Continued)

In March 1982, a primary to secondary leak in excess of the technical specification limit of 0.3 gallons per minute occurred in steam generator 'A'. Initial eddy current examination of possible leake_rs with the bobbin probe showed no new tube defects.

Subsequent examinations with a pancake type eddy current probe and additional bobbin probe examinations showed the leaking defects to be through wall with a circumferential orientation. At this point, Consumers Power Company committed to develop a pancake probe (4C4F) for use in the 1983 refueling outage.

The 1983 bobbin coil inspection confirmed that there was no degradation increase in the steam generators. However, a 100%

inspection of the steam generators with the 4C4F probe revealed a 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 were also characterized throughout both generators using the 4C4F probe.

Inspection techniques are used which separately or in combination are capable of measuring wastage and intergranular attack within the presence of dents.

In Specification 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 refueling outage, the long outage durations experienced at the Palisades Plant indicate a 30 month rather than a 24 month interval limit is appropriate to prevent unscheduled. shutdowns for inspection.

The inspection of a 6% sample of tubes in steam generator legs exhibiting leakage is intended to provide information as to whether or not degradation is increasing. The leaking tube(s) will not be included in the initial inspection sample results. Inclusion of the leaking tubes could distort the inspection results and lead to unnecessary inspections and personnel radiation exposure. Such tube leakage could be due to isolated effects rather than general degradation increases.

The supplementary sampling requirements in Specification 4.14.3 are intended to provide guidance in determining the appropriate action in the event that any of the criteria of Specification 4.14.3.1 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 cbange.

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 technique is based upon the findings of the qualification program. Details of the 4C4F technique qualification program are in the 1983/1984 Steam Generator Evaluation and Repair Report, Docket 50-255, License DPR-20.

4-69 Proposed TSP0987-0145-NL04