ML20140C780

Technical Evaluation Rept,Second Interval Inservice Insp Program,Arkansas Nuclear Power Plant Unit 1

ML20140C780
Person / Time
Site:	Arkansas Nuclear
Issue date:	10/31/1985
From:	SCIENCE APPLICATIONS INTERNATIONAL CORP. (FORMERLY
To:	NRC
Shared Package
ML20140C483	List: ML20140C478 ML20140C767 ML20140C780
References
CON-NRC-03-82-096, CON-NRC-3-82-96 SAIC-84-1661, NUDOCS 8601280401
Download: ML20140C780 (20)

Text

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Repor.t No. SAIC-84/1661 4L ,

TECHNICAL EVALUATION REPORT 4

SECOND INTERVAL INSERVICE INSPECTION PROGIAM ARKAl6AS MJCLEAR POWER PLANT UNIT 1 C ,I i

,i O Submitted to U.S. Maclear Regulatory Commission Contract No. MIC-03-82-096

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Submitted by O

Science Applications International Corporation Idaho Falls, Idaho 83402

0 October 1985 e601290401 PDR ADOCKOS%fth PDR G

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CONTENTS I NTRO D U CT IO N . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

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I. CLASS 1 COM P0 NENTS . . . . . . . . . . . . . . . . . . . . . 3 A. Re a cto r Ves s el . . . . . . . . . . . . . . . . . . . . . . . 3

l. Nozzle-to-Safe End Wel ds, Category B-F, I tem ' B 5.10 . . . . . . . . ........ . 3

8. Pressurizer ( No relief requests) g I

[ C. Heat Exchangers and Steam Generators (No relief requests) h D. Pi ping Press ure Boundary . . . . . . . . . . . . . . . . . . 5

1. %zzle-to-Safe End Wel ds , Category B-J, Item B9.11 . . . . . . . . . . . . . . . . . . . . . . . 5

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2. Circumferential Butt Welds, Category B-J, I tem B 9 . 21 . . . . . . . . . . . . . . . . . . . . . . . 8 E. Pump P res s u r e Bo un da ry . . . . . . . . . . . . . . . . . . . 11 g 1. Reactor Coolant Pump Casing Welds, Category B-L-l*, Item B12.10 .............. 11

2. Raactor Coolant Pump Internal Surface, Category B-L-2, Item B12. 20 .............. 13 O F. Valve Pressure Boundary (No relief requests)

II. CLASS 2 COMPONENTS (% reltef requests)

III. CLASS 3 COMPONENTS ( No relief requests)

O I V. PRESSURE TESTS (No relief requests)

V. GENERAL ( No relief requests)

VI. COM P0 NE NT S U PPO RTS . . . . . . . . . . . . . . . . . . . . . 16 l

A. Cl a s s 1 Su p p or ts . . . . . . . . . . . . . . . . . . . . . . 16

1. Reactor Vessel Support Skirt, Category F-A, I tem F1. 30 . . . . . . . . . . . . . . . . . . . . . . . 16 R EF ER EN CE S . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

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t TECHNICAL EVALUATION REPORT SECOND INTERVAL INSERVICE INSPECTION PR0mAM t

Arkansas % clear One Power Plant Unit 1

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INTRODUCTION -

This report evaluates requests for relief from certain examination and pressure test requirements of Section XI of the American Society of I Mechanical Engineers ( ASME) Boiler and Pressure Vessel Code

• by the O j licensee, Arkansas Power and Light Company ( AP&L), of the Arkansas Eclear One ( ANO-1) plant. The relief requests cover the second 120-month inspec- '

tion interval starting Decenter 19, 1984. The requests are based upon the 1980 Edition of Section XI, with Addenda through Winter 1981, as specified in the applicable revision of 10 CFR 50.55a.

'O The rest of this introduction summarizes (a) the scope of this report, (b) the previous review of re;lef requests by Science Applications Inter-national Corporation (SAlgl,i 8 and (c) the history of ANO-1 relief requests since the earlier review.t 2-10)

The current revision to 10 CFR 50.55a requires that Inservice Inspection O (ISI) programs be updated each 120 months to meet the requirements of newer editions of Section XI. Specifically, each program is to meet the require-ments (to the extent practical) of the edition and addenda of the Code incorporated in the regulation by reference in paragraph (b) 12 months before the start of the current 120-month interval.

O The regulation recognizes that the requirements of the later editions and addenda of the Code might not be practical to implement at facilities because of limitations due to design, geometry, and materials of con-struction of components and systems. Therefore, the regulation permits exceptions to impractical examination or testing requirements to be evalua ted. Relief from these requirements can be granted, provided the

,O i health and safety of the public are not endangered, giving due considera-l tion to the burden placed on the licensee if tne requirements were imposed.

This report only evaluates requests for relief dealing with inservice examinations of components and with system pressure tests. Inservice test programs for pumps and valves (IST programs) are being evaluated separately.

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• Hereinafter referred to asSection XI or Code.

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The current revision of the regulation also provides that ISI programs may meet the requirements of subsequent Code editions and addenda, incor-porated by reference in paragraph (b) and subject to % clear Regulatory i

Comission ( R'C) approval. Portions of such editions or addenda may be 4( used, provided that all related requirements of the respective editions or addenda are met.

Finally,Section XI of the Code provides for certain components and systems to be exempted from its requirements. In some instances, these j, exemptions are not acceptable to the RC or are only acceptable with .

res trictions.

In its previous Technical Evaluation Report (TER) dated September 17, 1982,(I J SAIC e~ valuated relief requests for ANO-1 covering the second and third 40-month inspection periods of the first inspection interval ( April jc / 19, 1978 to December 19, 1984). These requests were based on the 1974 j Edition with addenda through Summer 1975, the applicable Code in effect at the time. After the TER was submitted, Arkansas Power and Light submitted nine Nove2eradditional 12,1982,Lre]{gf requests J Noved for 1984, er 19, the fpit and Deceserst interval in letters 4t19, 1984. L These relief requests are being addressed separately in an addendum to

!O SAIC's first-interval TER.

The second inspection interval an was submitted on August 27, 1984.(5)

By letter dated hvember 20,1984,(p: 0? the RC requested additional infor-

!, ma tion. As a result of the additional information request submitted a revised second 10-year plan on(March and relief 8,1985,LI)t

0 requests by letter dated February 4, 1985. 8) A second request for addi-l tional inforgq f on based on the revised second 10-year plan was sent on

May 6,1985.L W T l June 24,1985.(10)he licensee responded to this request in his letter dated i

As a result of the above submittals, six relief requests for the second

}O i 10-year inspection interval have been identified as requiring disposition.

These requests are evaluated in the following sections of this report.

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I. CLASS 1 COMPONENTS A. Reactor Vessel

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1. Nozzle-to-Safe End Welds, Category B-F, Item B5.10 Code Requirement

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.M1 nozzle-to-safe end butt welds in nominal pipe size 4 in.

or greater in the reactor vessel shall be surface and volumetri-cally examined in accordance with Figure IWB-2500-8 during each inspection interval. The examinations nay be performed coincident

/ with the vessel nozzle examinations required by Category B-D.

.O j Dissimilar metal welds between combinations of (a) carbon or low alloy steels to high alloy steels, (b) carbon or low alloy steels to high nickel alloys, and (c) high alloy steel to high nickel alloys are included.

O Code Relief Request Relief is requested from surface examinations of circumferential welds for the two core flood nozzle-to-safe end welds (Nos.01-025 and 01-026).

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Proposed Alternative Examination Both core flood nozzle-to-safe ens welds would be 100%

C) volumetrically examined coincident with the vessel nozzle examinations from the vessel ID.

Licensee's Basis for Requesting Relief Access for a surface examination would require removal of the canal seal plate, shielding bricks, shielding supports in the nozzle areas, and insulation removal. Thir would require approximately 300 nanhours of work in a 700-1000 mR/hr area.

Evaluation The core flood tanks inject water directly into the reactor vessel following a break in the primary pressure-retaining boundary, thereby providing a vital source of water for reactor

. core cooling. The type of welds for which relief from surface 3

l examination has been requested has a history of inservice flaw initiation in a nunber of plants. Assurance that the welds and base metal in the core flood system are structurally sound must therefore be provided by either performing the required exami-

, nations or an alternative that will provide equivalent or superior .

resul ts. The increase in safety achieved by performing the required surface examination or an equivalent alternative outweighs the impracticalities cited by the licensee.

The licensee has proposed to eliminate the surface examina-(

tion but expand the required volumetric examination to cover 100'.

of the weld. This expanded volume would cover the cross section bounded by ACFEDB shown in Figure IWB-2500-8 of the 1980 Edition, Winter 1981 Addenda, and the examination would be conducted from the inside diameter. This alternative volumetric examination from j the inside diameter is not, however, sufficient in itself to pro-

'( . vide the degree of assurance necessary that outside diameter (0.D.)

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flaws will be detected. The licensee should either (1) demonstrate by the next refueling outage that 0.D. flaws can be detected using the proposed alternative volumetric examination or (2) perform the surface examination as required during the next refueling outage.

If the licensee chooses the first option, he should clearly

'O demonstrate that the actual procedure and instrument that would be used in the examination would detect 0.D. flaws in the existing confi guration. Re1ief from the surface examination should be granted for the subject welds until either of the conditions above is met or until the next refueling outage.

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Conclusions and Recommendations Based on the above evaluation, it is concluded that interim relief should be granted but only if the licensee meets either of

o the following conditions:

(a) Demonstrates by the next refueling outage that the actual procedure and instrument that would be used in the proposed examination would detect 0.D. flaws in the existing configuration.

C (b) Performs the surface examination requirement during the next refueling outage.

R_e ferences References 5, 7, and 8.

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L B. Pressurizer ib relief requests.

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C. Heat Exchangers and Steam Generators No relief requests. ,

D. Piping Pressure Boundary

1. %zzle-to-Safe End Welds, Category B-J, Item B9.11

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Code Requirement For circumferential welds with nominal pipe size 4 inches and greater, surface plus volumetric examinations in accordance with Figurs. IWB-2500-8 shall be pe" formed during each inspection

.O interval on essentially 100% of the weld. The examination shall include the following:

(a) All terminal ends in each pipe or branch run connected to vessels.

'O (b) All terminal ends and joints in each pipe or branch run con-nected to other components where the stress levels exceed the following limits under loads associated with specific seismic events and operational conditions:

(1 ) primary plus secondary stress intensity range of 2.4Sm O for ferritic steel and austenttic steel, and (2) cumulative usage factor U of 0.4.

(c) All dissimilar metal welds between combinations of C (1 ) carbon or low alloy steels to nigh alloy steels,

( 2) carbon or low alloy steels to high nickel alloys, and

( 3) high alloy steels to high nickel alloys.

(d) Additional piping welds so that the total equals 25% of the circumferential joints in the reactor coolant piping system.

This total does not include welds excluded by IWB-1220.

These additional welds may be located in one loop (one loep is currently defined for both PWR and 3WR plants in the 1980 Edi tion ).

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3 For welds in carbon or low alloy steels, only those welds showing reportable preservice transverse indications need be examined for transverse reflectors.

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Code Relief Request Relief is requested from surface examinations of circum-ferential welds for the two hot leg nozzle-to-safe and welds (Nos.

,01-019 and 01-022) in the Reactor Coolant System.

Proposed Alternative Examination C / Both hot leg nozzle-to-safe end welds will be 100%

j volumetrically examined coincident with the vessel nozzle examination from the vessel 10.

O Licensee's Basis for Requesting Relief Access for a surface examination would require removal of the canal seal plate, shielding bricks, shielding supports in the nozzle areas, and insulation removal. This would require approximately 300 manhours of work in a 700-1000 mR/hr area.

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Eval ua tion The licensee has proposed to eliminate the surface examina-

.O tion but expand the required volumetric examination to cover 100%

o f the wel d. This expanded volume would cover the cross section bounded by ACFEDB shown in Figure IWB-2500-8 of the 1980 Edition, Winter 1981 Addenda, and the examination would be conducted from the inside diameter. This alternative volumetric examination from the inside diameter is not, however, sufficient in itsel f to

O provide the degree of assurance necessary that outside diameter (0.D. ) flaws will be detected. The increase in safety achieved by performing the required surface examination or an equivalent alternative outweighs the impracticalities cited by the licensee.

The licensee should either (1) demonstrate by the next refueling outage that 0.0. flaws can be detected using the proposed alternative volumetric examination or (2) perform the surface examination as required during the next refueling outage. If the licensee chooses the first option, he should clearly demonstrate that the actual procedure and instrument that would be used in the examination would detect 0.D. flaws in the existing configura-tion . Relief from the surface examination should be granted for the subject welds until either of the conditions above is met or until the next refueling outage.

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C Conclusions and Recommendations Based on the above evaluation, it is concluded that interim relief should be granted but only if the licensee meets either of the following conditions: *

(a) Demonstrates by the next refueling outage that the actual procedure and instrument that would be used in the proposed examination would detect 0.0, flaws in the existing configuration.

(b ) Performs the surface examination requirement during the next refueling outage.

C E Re ferences References 5, 7, 8, 9, and 10, 4

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2. Circumferential Butt Welds, Category B-J, Item B9.21 Code Requirement For circumferential welds with nominal pipe size less than 4 inches, surface examinations in accordance with Figure IWB-2500-8 shall be performed during each inspection interval ,on essentially

, 100% of the weld. The examination shall include the following:

(a) All terminal ends in each pipe or branch run connected to vessels.

(b) All terminal ends and joints in each pipe or branch run con-( ) nected to other components where the stress levels exceed the following limits under loads associated with specific seismic events and operational conditions:

(1 ) primary plus secondary stress intensity range of 2.4Sm for ferritic steel and austenitic steel, and O'

( 2) cumulative usage factor U of 0.4.

(c) All dissimilar metal welds between conbinations of (1 ) carbon or low alloy steels to high alloy steels, O ( 2) carbon or low alloy steels to high nickel alloys, and

( 3) high alloy steels to high nickel alloys.

(d) Additional piping welds so that the total equals 25% of the O circumferential joints in the reactor coolant piping system.

This total does not include welds excluded by IWB-1220.

These additional welds may be located in one loop (one loop is currently defined for both PWR and BWR plants in the 1980 Edi tion ).

O Code Relief Request Relief is requested from making examinations of inaccessible circumferential welds which are as follows:

(1 ) High Pressure Injection Lines - Welds 20-008A,21-026, 23-024A, and 22-027A.

( 2) Core Flood Lines - Welds 19-020B and 19-021 A.

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Proposed Al ternative Examinations None. ,

1 Licensee's Basis for Requesting Relief High-pressure injection welds 20-008A,21-026,.23-024A, and 22-027A are inside penetrations Nos.13, 34, 8, and 15, respec-tively, in the shield wall and are not accessible for examination.

Core flood welds 19-020B and 19-021 A are inaccessible for j examination due to pipe supports. These welds were not examined 4

during baseline, and this fact is documented in the preoperational inspection report.

1C Evalua tion The identified welds are completely inaccessible for surface examination because the welds are located inside containment (3 penetrations or covered by pipe supports.

The welds can only be examined by inspecting for evidence of leakage during system hydrostatic pressure tests because the initial design of the assemblies did not provide for accessibility for inservice examinations. If, however, the workmanship and

() quality assurance of the welding are assumed adequate, then an examination of the first pressure boundary weld, on either side of the interference, adjacent to the inaccessible weld should reflect service-induced failures for diat particular piping section.

Thus, the first pressure boundary weld, on either side of the interference, adjacent to the inaccessible weld on each of these

() process pipes should be surface examined, where practical, over 100% of its length during each inspection interval. Such an examination would maintain sample size. The licensee should also conduct visual (VT-2) examinations for leakage during pressure tests, which would provide initia1' evidence of seepage from a through-wall perforation.

O Conclusions and Recommendations Based on die above evaluation, it is concluded that, for the welds discussed above, the Code requirements are impractical. It is further concluded that the alternative examination discussed

above will provide necessary added assurance of structural reli-abil i ty. Therefore, it is recommended that relief be granted from the surface examination of the identified welds with the following provisions

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(a) The first accessible pressure boundary weld, on either side of the interference, adjacent to the inaccessible g

weld on each of these process pipes should be examined -

by surface methods, where practical, over 100% of its length during each inspection interval.

(b) Visual examinations (VT-2) should be performed on the containment penetration assemblies when leakage and hydrostatic tests are conducted in accordance with

. IW A-5000.

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Re ferences References 5, 7, 8, 9, and 10.

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E. Pump Pressure Boundary

1. Reactor Coolant Pump Casing Welds, Category B-L-1, Item B12.10 i

Code Requirement Essentially 100% of the pressure-retaining welds in at least one pump in each group of pumps performing similar functions in the system (e.g., recirculating coolant pumps) shall be surface and volumetrically examined in accordance with Figure IWB-2500-16 during each inspection interval. The examinations may be performed at or near the end of the inspection interval.

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Code Relief Request Relief is requested from performing a 100% volumetric examination of the pressure-retaining weld in a reactor coolant O pump case weld.

Proposed Alternative Examination O Perform a volumetric examination of 95% of the reactor

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coolant pump case weld.

Licensee's Basis for Requesting Relief Only 95% of the pump case weld is accessible for examination using MINAC.

O Evaluation The Code requirement for examining pump case welds calls for essentially 100% of the weld. The Code uses the word essentially in an effort to give some leeway in performing examinations in restricted areas. A 95% examination of the weld meets with the intent of the Code requirement of a 100% volumetric examination.

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Conclusions and Recommendations ,

't Based on the above evaluation, it is concluded. that the scheduled examination meets the Code requirements. Therefore ,

relief is not required.

References

/ References 3, 4, 5, 7, 8, 9, and 10.

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2. Reactor Coolant Pump Internal Surface, Category 8-L-2, Item B12.20 i Code Requirement '

Visual (VT-3) examination of pump casing internal surfaces of at least one pump in each group of pumps performing similar functions shall be performed.

4 Code R'elief Request Relief is requested from performing visual inspections of

/ pump casing internal pressure boundary surfaces.

Proposed Alternative Examination O Partial surface replication, defined in Paragraph IWA-2215 of the Code, is obtainable from casing weld volumetric examination.

O Licensee's Basis, for Requesting Relief Pump casing internal surfaces are inaccessible without dismantling the pump. To do the required visual inspection of this pump's internal surfaces, large amounts of radiation exposure and time would be required. This was demonstrated at a similar O nuclear station, where an expenditure of approximataly 1000 man-hours and 50 man-rem were required to complete the visual inspection of a similarly designed pump. The large expenditure of man-rem and man-hours to complete the visual inspection of a perfectly good pump solely for the purpose of inspection is impractical and not commensurate to the increased safety achieved O by the inspection.

The licensee believes that adequate safety margins are inherent in the basic pump design and that the heal th and safety of the public will not be adversely affected by not performing the visual examination of the pump casing internal surfaces solely for the purpose of inspection.

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t Evaluation The visual examination is to determine whether unanticipated severe degradation of the casing is occurring due to phenomena

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such as erosion, corrosion, or cracking. However, previous experience during examinations of pumps at other plants has not shown any significant degradation of casings.

The disassembly of the reactor recirculation pumps to the degree necessary to inspect the internal pressure-retaining surfaces is a major effort, involving large personnel exposures and the generation of large amounts of radioactive waste. In view of the effort required to disassemble a pump, the information returned from visual examination of its internal surfaces would be marginal.

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/ A partial surface replication obtainable from casing weld volumetric examination will provide a significant amount of information about the pump interior surface conditions. This examination is more stringent than most licensees are per-formin g. However, if a pump requires disassembly for maintenance, an examination should be done by the most feasible means. The O alternative examination coupled with pump test data (as required by Subsection IWP) should provide adequate information about the pump interior surface.

g Conclusions and Recommendations Based on the evaluation, it is concluded that for the internal surfaces discussed above, the Code requirement is impracti cal . It is further concluded that the alternative examination discussed above will provide the necessary assurance O of structural reliability. Therefore, the following are recommended:

(a ) Relief from the Code-required visual examination of the interior surfaces of the pump should be granted.

O (b) The partial surface replication obtained from the casing weld volumetric examination should be accepted as an alternative examination of the internal pump casing surfa ces.

(c) If a pump requires disassembly for maintenance or any other reason, then the Code-required visual examination should be performd.

Re ferences References 5, 7, 8, 9, and 10.

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^t II. CLASS 2 COMPONENTS

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No relief requests. ,

J III. CLASS 3 COMPONENTS .

No relief requests.

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/ IV. PRESSLRE TESTS No relief requests. '

O V.- GENERAL No relief requests.

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t VI. COMPONENT SUPPORTS A. Class 1 Supports ,

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1. Reactor Vessel Support Skirt, Category F-A, Item F1.30 Code Requirement Coinponent supports selected for examination shall be the supports of those components that are required to be examined under IWB, IWC, and IWD during the first interval. For multiple compon-

) ents within a system of similar design, function, and service, the c j supports of only one of the multiple components are required to be examined.

h The examination method will be a visual, VT-3, covering the area defined in Figure IWF-1300-1.

O Code Relief Request Relief is requested from performing a visual examination of the reactor vessel support skirt weld as required by IWF of the "O 1980 Edition, Surmner 1981 Addenda of the Code.

Proposed Alternative Examination 5

0 None.

Licensee's Basis for Requesting Relief C

C The reactor vessel support skirt-to-vessel weld is impractical to examine visually because of the necessity for insulation removal and personnel exposures to a 150-200 mrem radiation field and a dose of approximately 1 rem on contact with the insulation. Wi th insulation removed, close proximity radiation readings are expected to be considerably higher.

Evaluation The licensee was allowed relief from performing a volumetric examination as required by the 1974 Edition, Summer 1975 Addenda of

the Code, during the first inspection interval. The Code of record 16

t for the second interval allows a visual examination, for which the licensee is also asking relief based on a high radiation field.

I Relief was recommended for the first interval based on the .

amount of time personnel would have to spend in a 150-200 mrem radiation field to obtain a meaningful volumetric examination.

In addition, the evaluation of the relief request included a recomendation that the ifcensee perform the required visual examination early in the second interval.

The stated radiation field is 150 to 200 mrem and while the field is certainly higher with the insulation removed, the licensee has not provided any estimates. This weld is a very important reactor vessel support weld that has not yet had any inservice inspection . The weld will not show telltale signs of cracking, I such as leakage from a pressure boundary, without an examination.

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A visual examination of the weld can be performed with less radiation exposure than can a volumetric examination because less time is involved in the examination. The stated radiation level is an acceptable field in which to perform this important examination.

Thus, the licensee should perform a 100% visual examination during the next refueling outage.

O Conclusions and Recommendations g Based on the above evaluation, it is concluded that the Code requirement is nbt impractical. Therefore, it is recommended that relief from the requirement of visual examination of the reactor vessel support skirt weld not be granted. It is further recom-mended that the licensee be required to perform 100*. of the required visual examination during the next refueling outage.

O Re ferences C

References 5, 7, 9, and 10.

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I REFERENCES 1

1. Science Applications, Inc., Arkansas Nuclear One-Unit 1, Inservice Inspection Program Technical Evaluation Report, 186-028-39, September 17, 1982.

2. Letter, J. R. Marshall ( AP&L) to J. F. Stolz (NRC), November 12, 1982; relief requests for first interval.

3. Letter, J. T. Enos ( AP&L) to J. F. Stolz (NRC), November 19, 1984; relief request.

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4. Letter, J. T. Enos ( AP&L) to J. F. Stolz (NRC), December 19, 1984; relief request.

5. Letter, J. R. Marshall ( AP&L) to J. F. Stolz (NRC), August 27, 1984; issued second interval program.

6. Letter, J. F. Stolz (NRC) to J. M. Griffin ( AP&L), November 20, 1984;

() request for additional information on first and second interval ISI.

7. Letter, J. T. Enor ' AP&L) to J. F. Stolz (NRC), March 8,1985; revised AN)-1 Second 10-Year Inservice Inspection Program submittal.

c) 8. Letter, J. T. Enos ( AP&L) to J. F. Stolz (NRC), February 4,1985; ISI second 10-year faterval relief requests.

9. Letter, J. F. Stolz ( NRC) to J. Griffin ( AP&L), May 6,1985; request for additional inforcation on first and second interval ISI.

() 10. Letter, J. T. Enos ( AP&L) to J. F. Stolz (NRC), June 24, 1985; res ponse to request for additicatil information.

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