ML18051B043

Safety Evaluation Supporting Licensee Request for Relief from Inservice Insp Requirements

ML18051B043
Person / Time
Site:	Palisades
Issue date:	08/23/1984
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML18051B042	List: ML18051B041 ML18051B043
References
NUDOCS 8408300132
Download: ML18051B043 (11)

Text

e UNITED STATES e

NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORT FOR RELIEF FROM INSERVICE INSPECTION REQUIREMENTS CONSUMERS POWER COMPANY 1.0 lNTRODUCTION PALISADES PLANT DOCKET NO. 50-255 I~,*,\\\\, 1" By letter dated October 15, 1979,*Amendment No. 50 to Provisional Operating License No. DPR-20 was issued for the Palisades Plant. This amendment revised, in part, the Technical Specifications to replace the then existing inservice inspection requirements with a program in compliance with the requirements of 10 CFR 5Q.55a.

The revised program met the requirements in the 1974 Edition through Summer 1975 Addenda of Sec ti on XI of. -the ASME Boi 1 er and Pressure Vessel Code for examination of Class 1, 2, and 3~piping and components with relief granted for impractical requirements __ as $llowed by 10 CFR 50.55a.

By letter dated November 12, 1980 supplemented by submittal dated November 16, 1982, Consumers Power Company submitted an Inser-vice Inspection Program updating the examination requirements from those contained in the 1974 Edition through Summer 1975 Addenda to the requirements contain~_d in the 1977 Edition through*

Summer 1978 Addenda.

Updating to a later edition of Section XI which has been approved by the Commission is allowed by 10 CFR.50.55a.

For those requirements in the later edition that have been determined to be impractical to meet, the licensee is required to notify the Commission and submit a request for relief from the specific requirement along with information to support his determina-tion.

Examination requirements which have been determined by the licensee to be impractical to perform at the Palisades Plant and the supporting information have been provided in the letters dated November 12, 1980 and November 16, 1982.

The requests and information will be evaluated in this report and relief granted from the examination requirements if the necessary findings are made.

2.0 EVALUATION OF REQUESTS A.

Class 1 Components

1.

(RR-1) Relief is requested from examination of circumferential and meridional welds in the reactor vessel closure and bottom heads.

(Items Bl.21 and Bl.22, Examination Category B-A).

Code Requirement Volumetric examination shall be performed on 100% of the accessible lengths of all welds in the closure and bottom heads during the first inspection interval.

Exa~ination of-welds in the.bottom head may be deferred to the end of the inspection interval.

Licensee Basis for Requesting Relief The dollar plate weld in the closure head is inaccessible for volumetric examination due to control rod guide tube constraints. Meridional welds in the closure he~d are partially accessible for volumetric examination.

An attempt will be made to volumetrically inspect the meridional and circumferential seam welds in the bottom-head during the next refueling outage in which mechanized inspection will be performed on the Reactor Vessel.

Evaluation and Conclusion The *control rod guide tubes which penetrate the reactor vessel closure head cause the dolla_r plate weld to be inaccessible for volumetric examinatio~. The licensee will attemp~ to~examine the circumferential and meridional welds in the bottom head.

The Code requires examination of the accessible lengths of the welds in the closure and bottom heads.

The licensee is in compliance with the Coo~ requirements and, therefore, relief is not necessary.

2.

• (RR-2) It is requested that the transition pieces between the carbon steel nozzles and carbon steel piping on the reactor vessel and steam generators be classifi*ed Category B-J instead of B-F and that the examina-tion frequency for Category B-J apply.

Code Requirement Category B-F:

All nozzle-to-safe end welds shall be examined by volumetric and surface methods each inspection interval.

Category B-J:

Circumferential welds at all terminal ends in each pipe or branch run connected to vessels shall be examined by volumetric and surface methods each inspection interval.

Licensee Basis for Requesting Relief The transition pieces between the carbon steel nozzles and the carbon steel piping are also carbon steel and thus are not dissimilar metal safe ends.

The nozzle safe end welds~are, therefore, classed as 89.1~~**..

B-J welds rather than 85.10 and 85.30, B-F welds.

Licensee Proposed Examination These welds should be included and inspected to Category B-J requirements with the restriction that the inspection be expanded to include 100% of each weld during each inspection interval.

However, this examination could be included in the 25% examination requirements of Category 8-J welds.

Evaluation and Conclusion The reactor vessel and steam generator 11nozzle-to-transition pieces 11 are not dissimilar metal welds and, therefore, should be categorized as B-J.

However, the transition pieces are termtnal ends and are required to be volumetrically and surface examined each inspection interval as proposed by the licensee and required by the Code.

~-

3.

(RR-3) Relief is requested from performing \\/ital examination o*f the nonperipheral CROM bolting.

(Item 87.lO~~xamination Category B-G-2).

Code Requirement Visual examination (VT-1) shall be performed on all bolts, studs, and nuts during the inspection interval. Bolting may be examined either (a) in place under tension, (b) when the connection is disassembled, or*(c) when the bolting is removed.

Licensee Basis for Requesting Relief CROM bolting is not generally accessible for VT examination due to the configuration of the CRDMs.

The peripheral CROM bolting is accessible.

All nonperipheral CROM bolting is not accessible for VT examination.

Peripheral CROM pressure-retaining ~olting will be VT-1 examined.

However, if the inne~ CROM assemblies are disassembled or the bolting removed, visual examination as required by the Code shall be performed.

Evaluation and Conclusion The inaccessibility of the inner CRDMs prevents visual examination of the bolting as required by the Code when the CRDMs are in place.

The peripheral CROM bolting will be examined in pccor9ance with Code require-ments and the bolting of any inner CRbMs which are removed will also be examined.

The staff finds that the bolting committed to be examined by the licensee representi a significant sample of the total number and will provide assurance of the bolting structural integrity.

The staff, therefore, concludes that the relief may be granted.

4.

(RR-4) Relief is requested from performing the surface examination requirement for the following welds (Item 9.11 and 9.12, Examination Category B-J).

PCS-42-RCL-lH-1, 2 PCS-42-RCL-2H-l, 2 PCS-30-RCL-lA-15, 15LD-l, 15LD-2, 16LU-l, 16LU-2, 16 PCS-30-RCL-18-13, 13LD-l, 13LD-2, 14LU-l, 14LU-2,14 PCS-30-RCL-2A-14, 14LD-l, 14LD-2, 15LU-1-, 15LU-2, 15 PCS-30-RCL-28-14, 14LD-l, 14LD-2, 15LU-l, 1*5LU-2, 15 Code Requirement Surface and volumetric examinations shal--r-t-e performed on essentially 100% of the weld length during the inspe_ction interval.

• Licensee Basis for Requesting Relief Piping welds adjacent.to the reactor vessel and buried in the cement reactor vessel shield are inaccessible for OD examination.

The surface examination cannot be performed.

The volumetric examination of these welds can be performed from the ID using a mechanized device.

All welds identified above shall be ~xamined from the ID volumetrically.

The weld will be 100% examined (in lieu of the bottom 1/3 required by Section XI, 77578, Figure IWB-2500-8).

The surface exam will not be performed due to inaccessibility.

Evaluation and Conclusion The piping welds listed are inaccessible for surface examination because they are buried in the cement reactor vessel shield.

The licensee has committed to increase the required examination volume from the bottom one-third to include the volume bounded by the pipe O.D. and I.D. and one-half inch on both sides of the weld.

The increase volume examination will cover near-surface O.D. cracks (if any exist) and is an adequate alternative for the required O.D. surface examination.

The staff concludes that adequate assurance of the structural integrity of the welds and heat-affected zones will be provided by the examination committed to by the licensee. Therefore, relief from the surface examination requirement may be granted.

5.

(RR-5) It is requested that hole-type reflectors in lieu of notch-type reflectors be used for calibration blocks for pressure-retaining piping welds when ultrasonic examinations are performed on piping thicker than 0.400 11 (See 3.0 below)

Code Requirement IWA-2232:

Ultrasonic examination of Class 1 and Class 2 ferritic steel piping systems shall be cond8cted ~n accordance with Appendix III.

III-3430 Calibration Notches:

Basic calibration blocks shall contain circumferential and longitudinal notches whose sides are perpendicular to the surface, at least 1.0 in. long, on the 0.0. and I.D. surfaces.

IWA~2240 Alternative Examinations: Alternative examination methods, a combination of methods, or newly deveJoped techniques may be substituted fQf. the methods specified, provided the-inspector is satisfied that the r~iults are demonstrated to be equivalent &r superior to thos~ of the specified m~thod.

Licensee Basis for Request ASME B&PV Code,Section XI 1977 Edition with Addenda through Summer 1978, paragraph IWA-2232(b) requires the utilization of Appendix III,Section XI for ultrasonic examinations for piping.

Appendix III, paragraph III-llOO(d) permits the utilization of alternative examination techniques and calibration block design in accordance with IWA-2240 (Alternative Examinations).

Consumers Power Company elects to utilize hole-type reflectors in lieu of notch type reflectors required by paragraph III-3430 for ultrasonic examinations performed on piping thicker than 0. 400 11 In order to effect the change in reflector type, Consumers Power Company elects, per IWA-2232, to conduct ultrasonic examinations of piping welds in accordance with Article 5,Section V, ASME Code.

The requirements of Article 5, S.ection V will be modffied by the attached code applicability statements.

(See 3.0 ULTRASONIC EXAMINATION METHOD)

Utilization of hole type reflectors for material thicker than 0.400 11 in lieu of notch type reflectors will increase the sensitivity of the examination by a factor of two (2) over the standard 45° angle beam examination.

Consumers Power Company will implement the two code applic-ability statements attached in order to effect this change in reflectors.

The code applicability statements will enhance procedure and calibration control, and control of calibration block procurement/fabrication.

(See 3.0 below)

Evaluation and Conclusion The use of Article 5,Section V of the ASME Code is permitted for selec-tion of calibration reflectors.

As stated in T-547.1.3.4 of Article 5,Section V, 11a side-drilled hole may b~ used for initial acceptance of a pipe weld, provided that it can be demonstrated that the hole calibration produces a sensitivity equal to or greater than the notch calibration.

6.

(RR-6) Relief is requested from examination of the following welds (Items 89.11 and 89.12, Examination Category B-J).

PCS-42-RCL-1Hl-2LD, -3LU, -3, -3LD PCS-42-RCL-2Hl-2LD, -3LU, -3, -3LD Code Requirement Surface and volumetric examination shall be performed on essentially 100%

of the weld length during the inspection interval.

Licensee Basis for Requesting Relief ---

The area -between the* last known weld (at trre e1bow entrance to the steam*

generator) *and the reactor vessel shield was visually examined; no welds were apparent in this region.

Therefore, ft is concluded that the welds are buried inside the reactor shield.

The welds identified above shall be visually inspected by observing the

• general area after a four-hour hold.at the pressure test requirements stated in Section XI.

Evaluation and Conclusion The welds listed are apparently buried in the reactor vessel shield and inaccessible for volumetric and surface examinations.

The only feasible nondestructive examination which can be performed to determine the welds' structural integrity is a visual examination of the areas where the pipes penetrate the reactor vessel shield.

The licensee has committed to perform the visual examination in accordance with Section XI requirements for insulated piping.

At the test temperature and pressure requirement along with the four-hour hold time, leakage from a throughwall crack in the buried pipe should be indirectly detected by wetting of the cement shield wall.

Considering the inaccessibility of the pipe welds, the burden which*the licensee would encounter if the requirements were imposed, and the assurance of the structural integrity provided by the visual examina-tion of the areas around the pipes penetrating the shield wall, the staff concludes that relief from volumetric and surface examinations may be granted.

B.

Class 2 Components

1.

(RR-7) Relief is requested from examination of the following welds (Item C5.11, Examination Category C-F):

ESS-24-SIS-SHl-201, -202, -203, and -204 ESS-24-SIS-SH2-201, -202, -203, and -204 Code Requirement Surface examination shall be performed on 100% of each pressure-retaining piping weld each inspection interval.

Licensee Basis for Requesting Reli~f The welds listed are encased in steel plate missile shields and are inaccessible for NOT examination.

The welds identified shall be examined visually for evidence of leakage by observing the general area after the four~hour hold time at the pressure test reqµirements as stated in IWC-5000.

Evaluation and Conclusion The outside surfaces of the welds listed are inaccessible for *surface examination. as required by the Code becarrs-e-they are encased in steel plate missile shields. Because of the iraccessibility of the welds, other NOE methods (PT, RT, UT) also cannot be applied.

The only feasible examination is a visual inspection of the general area of the welds during the hydrostatic test of the piping system.

The licensee has committed to perform the visual examination.

The staff finds the visual examination acceptable and concludes that relief may be granted.

3.0 ULTRASONIC EXAMINATION METHOD A.

Consumers Power Company Code Applicability Statement No. 1

Subject:

Piping Examination The basic requirements for ultrasonic examination of piping shall be in accordance with the following:

Type of Materi a 1 Austenitic and Ferritic piping and dissimilar metal welds Austenitic and Ferritic piping and dissimilar metal welds Nominal Thickness Greater than.4 to 6 in.

.1 to. 4 in.

Applfcable Code Article 5 of ASME Section V with addenda through Summer 1978 Appendix III with Supp-1 ement 7 of ASME Section XI with addenda through Summer 1978

1.

The following modifications of the requirements of Article 5 Section V, and Appendix III,Section XI, 77S78 addenda are applicable.

z.

3.

4.

(a)

Code Case N-211 Recalibration for Ultrasonic Equipment Upon Change of Personnel;.

(b)

Code Case N-234 Time Between Ultrasonic Calibration ChecksSection XI Division 1; and (c)

Code Case N-235 Ultrasonic Calibration Checks per Section V,Section XI, Division 1.

For examinations conducted in accordance with Article 5 of ASME Section V, the basic calibration block for production material thickness 1.0 11 or less shall be as follows:

The basic calibration block shall have the same nominal thickness as the production material or no more than 25%

less than the nominal production material thickness or closer in thickness to the production material than the.3/4-inch alternate thickness allowed by Article 5.

This modification will assure a more accurate calibration than the basic calibration block design-allowed by the code. -

• subparagraph T-535.f{d)(l) and (2) of*Artic~le 5 requires that transfer (attenuation compensation) be accomplished between the production material and the basic calibration block arld a correction made* for the difference.

In accordance with Code Inter-pretation V-78-01 and Code Case 1698 (N-92), the transfer method wiJ l."not be used.

Attenuation measurements will be recorded and considered during analysis and evaluation

• of indications, however, no attempt.will be made by the examiner to compensate for any observed difference before or during the ultrasonic examination.

For examination conducted on welds, the following requirements from Appendix III,Section XI 77S78 shall be used in lieu of paragraph T-530,Section V, 77S78.

III-2300 III-2400 III-3100 II I-3210 II I-3300 III-3500 III-4000 Written Procedure Requirements General Examination Requirements Instrument Calibration (to include Suppl. 5 and 6)

System Calibration - General Requirements Calibration Confirmation Calibration Data Record Examination

5.

Data shall be recorded as per IWA-2232(b).

B.

Consumers Power Company Code Applicability Statement No. 2

Subject:

UT Piping Calibration Blocks All and

1.

2.

new piping ultrasonic calibration blocks will be procured, designed, fabricated as follows:

Materi a 1 Basic calibration block material shall conform to the requirements paragraph III-3411,Section XI.

Radius of Curvature Basic calibration blocks shall conform to the radius of curvature required by paragraph III-3410, Section~!.

1:.. 1(***

of

3.

Thickness Basic calibration blocks shall conform to the requirements of paragraph III-.3410.

4.

Calibration Reflectors TbJckness:

.10 11 to.40 11 Calibration. reflectors shall be holes an~all conform to the require-ments of paragraph T-533 (a), Article 5,Section V, 77578 ASME B&PV Code.

C.

Inservice Inspection Code Case Utilization Consumers Power Company elects per 10 CFR 50.55a(2)(ii) and Footnote 6 to 10 CFR 50.55a to utilize the following ASME Code Cases as an integral part of the Inservice Inspection Programs for the Palisades Plant.

Code Case N-98 Ultrasoni~-~xamination - Calibration Block Tolerance Code Case B-211 Recalibration of Ultrasonic Equipment Upon Change of Personnel Code Case N-234 Time Between Ultrasonic Calibration Checks Code Case N-235 Ultrasonic Calibration Checks per Section V Code Case N-:'278 Alternative Ultrasonic Calibration Block Configuration Evaluation and Conclusion The staff has reviewed Consumers Power Company's proposed ultrasonic methods, applicability statements, and the Code cases to be applied.

The staff finds the methods to be in compliance with the Code and concludes that they are acceptable.

4.0 GENERAL REQUIREMENTS A.

Application of IWB-2430 and IWC-2430, Additional Examinations

( RR-6 and RR-7)

Code Requirement

1.

Examinations performed during any inspection that reveal indications exceeding the allowable indications standards of IWB-3000 or IWC-3000 shall be extended to include an additional number of components (or areas) within the same examination category, approximately equal to the number of components (or areas) examined initially during the inspection..

2.

If the additional examinations reveal further indications exceeding the allowable standards, the remaining number of similar components (or*areas) within the same examination category shall be examined to the extent specified in Table IWB-2500-1 or IWC-2500-1 except as modified by (c).and (d) below~.

3.

• Where the required piping examinatfons are limited to on loop or branch run of an essentially symmetric-piping configuration, examinations that reveal indications e'xceed1ng the allowable indic~tions standards of IWB-3000 ur IWC-3000 shall require the additional examinations of (a) above and shall be extende*d to include examination of a second loop-qr branch run to the extent specified in Table IWB-2500-1 or IWC-2500-1.

• 4, If the examination of the second loop or branch run reveals further indications exceeding the allowable standards of IWB-3000 or IWC-3000, the remaining number of loops or branch runs that perform similar functions shall be examined.

Licensee Proposed Method of Selecting Additional Welds The application of IWB-2430 a~d IWC-2430 at the Palisades Plant is a two-step process:

(1) the first step adds generally the same number of welds (same S.ection XI Item Number) on the component/line of interest as was originally scheduled and (2) the second (required by the detection of a defect in the examinations added pursuant to finding the original defect) results in the remainder of the line/component (with the same Section XI Item No.) being examined; Evaluation and Conclusion The two-step method of selecting additional welds as proposed by the licensee is a conservative selection method when applied to the welds listed under RR-6 and RR-7.

However, application of IWB-2430 and IWC-2430 has to consider multiple streams when defects are found in the single loop or branch subject to examination.

The licensee's method of selection of additional welds is accevtable provided that the selection methods are. applied to multiple streams in the event defects are found in the single stream.

-1

11 -

5.0 CONCLUSION

The NRC staff concludes that where stated the Code requirements are impractical, the granting of this relief is authorized by law and will not endanger life or property or the common defense and security, and is otherwise in the public,,,....

interest considering the burden that would result if they were imposed on

'::*i*

the licensee.

Pursuant to 10 CFR 51.32, the Commission has determined that the issuance of the relief will have no significant impact on the environment (August 23, 1984 49 FR 33511).

Dated:

August 23, 1984