ML19209C233

IE Bulletin 79-14,Safety-Related Piping Sys,Phase 2 Accessible Piping Insp Rept,

ML19209C233
Person / Time
Site:	Monticello
Issue date:	10/08/1979
From:	Higginbotham A, Mcwilliams D, Vagel T NUTECH ENGINEERS, INC.
To:
Shared Package
ML112900941	List: ML19209C233
References
NSP-37-031, NSP-37-31, NUDOCS 7910120231
Download: ML19209C233 (73)

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NSP-37-031 Revision 0 October 8, 1979 IE BULLETIN 79-14 SAFETY RELATED PIPING SYSTEMS PHASE 2 ACCESSIBLE PIPING INSPECTION REPORT MONTICELLO NUCLEAR GENERATING PLANT Prepared for:

Northern States Power Company Prepared by:

NUTECH PEepar d by: Approved and Issued by:

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NSP-37-031

- Revision 0 Specification: NSP-37-031 Description I2 Bulletin 79-14 Safety Related Piping Systems Phase 2 Accessible Piping Inspection Report Monticello Nuclear Generation Plant Prep. Chk.

Rev. Date B2 & Pages Remarks 0 10/5/79 TNV DKM All Initial Issue M

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NSP-37-031 Revision 0 PREFACE On July 2, 1979, the United States Nuclear Regulatory Commission issued IE Bulletin 79-14, " Seismic Analysis for As-Built Safety Related Piping Systems" . The issue addressed in the Bulletin is that input used for seismic analysis of safety-related piping systems may not be representative of the as-built configuration.

The Bulletin requires that each utility compare the as-built

] configuration of the piping systems to the input information used for the seismic analyses. All nonconformances that are identified in the inspection must be evaluated for their effects on system operability.

The inspections of the piping systems are being performed in two phases. The Phase 1 inspection covers one system in each set of redundant, normally accessible systems and all non-redundant accessible systems. The remaining redundant systems and the inaccessible systems are being inspected in Phase 2.

A summary report for the Phase 1 inspections for the Monticello Nuclear Generating Plant was issued on September 21 , 1979. The purpose of this document is to present the results of the inspections of the Phase 2 accessible piping systems at the plant. The Phase 2 inaccessible systems will be covered in a aubsequent inspection report.

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NSP-37-031 Revision 0 TABLE OF CONTENTS Page LIST OF TABLES............................................iv LIST OF FIGURES...........................................iv

1.0 INTRODUCTION

.............................................. 1 2.0 SYSTEMS INSPECTED......................................... 3

3.0 DESCRIPTION

OF THE PHASE 2 ACCESSIBLE PIPING INSPECTION... 5 3.1 As-Built In s p e c t i o n . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 3.2 Compilation of Analysis Input Data................... 5 3.3 Correlation of As-Built and Analytical Data. . . . . . . . . . 6 4.0 REPORTING AND RESOLUTION OF DISCREPANCIES................ 11 5.0

SUMMARY

OF DISCREPANCIES IDENTIFIED DURING THE .......... 13 PHASE 2 ACCESSIBLE PIPING INSPECTION 5.1 Discrepancies Resolved by Engineering Judgment. . . . . . 13 5.2 Discrepancies Requiring Further Analysis to ........ 13 Evaluate Operability 5.3 Discrepancies Requiring Further Analysis to ........ 13 Evaluate FSAR Compliance 5.4 Discrepancies Identified During the Field Inspection.14

6.0 CONCLUSION

............................................... 16

7.0 REFERENCES

............................................... 17 m

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NSP-37-031 Revision Q LIST OF TABLES Page TABLE 2.1 ACCESSIBLE PHASE 2 PIPING SYSTEMS............. 4 TABLE 3.1 INSPECTION DATA .............................. 7 TABLE 3.2 INSPECTION CORRELATION TOLERANCES............. 8 TABLE 5.1 LINES REQUIRING REANALYSIS TO EVALUATE. . . . . . . 15 FSL2 COMPLIANCE LIST OF FIGURES Page FIGURE 3.1 DISCREPANCY F0RM.............................. 9 FIGURE 3.2 NONCONFORMANCE REPORT........................ 10 w

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1.0 INTRODUCTION

Recently, the United States Nuclear Regulatory Commission (NRC) identified a series of genetic issues which could potentially 1

cause the se'saic analysis of safety-related piping systems to yield ,3ccurate results. One of these issues involves the cor-relation of the as-built piping configuration and the information used for the seismic analysis of the piping system.

Due to this concern, the NRC published IE Bulletin 79-14 (Refer-ence 1), and the subsequent supplements to the Bulletin (Reference 2) , which require that an inspection be conducted to verify that the input information for the seismic analysis of safety-related piping systems reflect as-built configurations.

Further, the Bulletin requires that, where deviations are found, the licensee must consider the need to reevaluate the seismic analysis to the as-built configuration or modify the hardware.

On July 31, 1979, an Inspection Plan (Reference 3) was issued to describe the inspections to be conducted on the Seismic Category I and safety-related piping systems at Northern States Power Company's Monticello Nuclear Generating Plant. Subsequently on August 30, 1979, a revision to the Inspection Plan (Reference 4) was issued incorporating all new Bulletin requirements. The inspections compare the as-built configuration to the information which is required for the seismic analysis of the piping, e.g.,

piping size and wall thickness, piping configuration geometry, valve locations, valve operator orientations, support locations, and type of support. As described in the IE Bulletin and the Inspection Plan, the inspections are being performed in two phases. The Phase 1 inspections cover one system in each set of

_ redundant, normally accessible systems and all non-redundant accessible systems. The remaining redundant systems and the inaccessible systems are included in the Phase 2 inspections. -

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NSP-37-031 Revision 0 This document reports the results of the inspections conducted on the Phase 2 accessible systems. These systems are defined in Section 2 with the details of the various tasks associated with the inspection being described in Section 3 The general procedures for resolving all discrepancies and the discrepancies that have been identified are provided in Section 4 and Section 5, respectively.

Based on engineering judgement, it is concluded that none of the I discrepancies would impair operability. However, computer analysis was deemed necessary to demonstrate compliance with the original design requirements specified in the FSAR (Reference 5) for three lines. As indicated in Section 5 two of the three analyses have been completed. The analysis of the third line is in progress and is scheduled to be completed by October 31, 1979.

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NSP-37-031 Revision 0 2.0 SYSTEMS INSPECTED During July, August and September of 1979, NUTECH with support from Northern States Power Company (NSP) and Bechtel Power Corporation (Bechtel) conducted an inspection of the accessible Phase 2 piping systems at the Monticello Nuclear Generating Plant. These systems consist of the second side of all redundant accessible Seismic Category I and safety-related systems with outside diameters of 2-1/2 inches or greate. which are accessible for inspection. The list of the Seismic Category I and safety-related systems cons.dered 4

under Phase 2 is given in Table 2.1 along with the applicable line segments and isometric drawing numbers used in the comparison.

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NSP-37-031 Revision 0 TABLE 2.1 ACCESSIBLE PHASE 2 PIPING SYSTEMS APPLICABLE REFERENCE SYSTEM LINE SEGMENTS DRAWING NUMBER TW6-1211E 6350 CORE TW7-10GE 6400 TW7-8ED, EF 6400 SPRAY TW8-8GE, HE 6400 TW9-2 GE, HE 6411 SW10-12GF 6429 RilR SW10-18GF 5451,6429,6424 SERVICE SW10-16GF 6424 WATER SW12-16GF 6346 EMERGENCY SW25-4HF 6401,6431 SERVICE SW30B-3HF 6446,6431 WATER TW21-3HE 6425 I TW22-14GE TW23-12GE TW23-10GE 6348 6425 6425 TW 24 - 12GE ,IIE 6425 TW 2 5 - 4 GE ,IIE 6425 TW27-20llE 6347 TW14A-1811E (Valve) 6347 RilR TW14A-20llB (Valve) 6347 I TW15-1411E 6347 TW17-14HE 6347 I TW19-10GE TW19-14GE TW20-14GE 6348 6348 6348 TW20-16GE 6348 D82-3-HE SK-L-285 ,

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NSP-37-031 Revision 0

3.0 DESCRIPTION

OF THE PHI . 2 ACCESSIBLE PIPING INSPECTION The Phase 2 accessible inspection consisted of three separate tasks: (1) an as-built inspection of the piping systems at the plant site, (2) a compilation of the input data used for the piping analyses, and (3) a correlation of the results from tasks 1 and 2 above to show conformance/nonconformance between the installed and analyzed piping. The details associated with each task are described in the following sections.

3.1 As-Built Inspection NUTECH, with support from NSP, performed the as-built inspection of the Phase 2 accessible piping systems. The inspection consisted of measuring and recording physical dimensions and hardware information in enough detail to allow a complete

__ comparison with the analysis input data. The information gathered at the site and the methods used to obtain the data are provided in Table 3.1.

Prior to the inspection, dat. books were prepared for each system. These books specify the dimensions and other information to be gathered at the site and are based on the drawings listed in Table 2 .1 . The completed, signed, and approved data books

_ were maintained at the site until completion of the Phase 2 accessible piping site inspection at which time the taoks were transferred to the NUTECH offices in San Jo s e , California, to be used for the work described in Section 3.3 3.2 Compilation of Analysis Input Data

_ Bechtel compiled the input data used for the analysis .of the E

piping systems. This work effort consisted of organizitig dimen-sions and information used in the piping stress analysis in the form of piping stress isometrics and supporting data.

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I 3.3 Correlation of As-Built and Analytical Data NUTECH, with the help of Bechtel, correlated the results of the irspections described in Sections 3.1 and 3.2, and identified Discrepancies by completing the discrepancy form shown in Figure 3.1.

I The as-built data and the analytical data were considered in conformance so long as the as-built to as-analyzed differences I remained within the tolerances specified in Table 3.2. These tolerances, while allowing for some deviation, are sufficiently restrictive to ensure system operability under specified earth-quake loadings. Any measuremant which exceeded the specified tolerance limit wes identified as a descrepancy and evaluated in accordance with the requirements of Section 4.

5 In addition , any discrepancies requiring repair which were found at the time oi the site inspection were reported to NSP via a Nonconformance Report form , Figure 3.2. These included primarily conditions such as loose bolts, etc.

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NSP-37-031 Revision 0 TABLE 3.1 INSPECTION DATA TYPE OF METHOD OF FIELD VERIFICATION IF DATA VERIFICATION OTHEP THAN FIELD I. Piping Ihta(I) m a. Size Tape Measurement of Ciremfer-

> ence

b. Wall-nickness Ultrasonic Digital n ickness Gage

c. Configuration Tape Measurement of Iengths

d. Branch Connec- Visual Caparison with Fab.

tion Drawings

e. Material N/A Q.A. Inspection i Report (Reference 6)

II. Insulation n ickness Tape Measurement of n ickness III. In-Line Eqpt.

a. Valves

1. Iocation Tape Measurement of Pipe length

2. Operator Visual Inspection Orier_Lation

3. Kaight N/A Vendor / Vendor Dwg./

Eng. Judgment

b. Other Large Equipment

1. Location Tape Measu ment of Pipe length

2. Weight N/A vendor / Vendor Dwg.

IV. Supports

a. location Tape Measurement of Pipe length

b. Type Visual Comparison with Fab.

Drawing

c. Anchorage Visual C mparison with Fab.

Drawing

d. Orientation Visual Inspection

e. Size or load Visual Cmparison

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Capacity

f. Design and Visual Caparison Assembly De-tails.

V. Clearance

a. Floor or Wall Visual Inspection Penetrations

b. Directional Visual Inspection Changes NorE 1: For insulated iping ~ data was obtained by removing

• insulation an provi g direct access to the system.

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NSP- 3 7- 031 Revision 0 TABLE 3.2 1

INSPECTION CORRELATION TOLERANCES TYPE OF DATA TOLERANCE m I. Piping Data

a. Size (Outside Diameter) + 5% of OD

b. Wall thickness T 12% of nominal thickness

c. Configuration Ru of + 5% of straight run length, 6" or 10

d. Branch Connection Same Type

e. Material Same type as @ inspection document II. Insulation

a. Type Same type

b. Thickness + 20%

III. In-Line Equipment

a. Valves

1. Location Max gf + 5% of straight nm length, 6" or 1 OD

2. Operator Orientation -+ 15 Er operator angle

3. Weight 10% of total weight IV. Supports

a. Location 6" for pipe sizes < 4" 2 pipe diameters for pipe size > 4" but < 12" 24" Er pipe size > 12"

b. Type Same type as design documents

c. Anchorage Samg as design drawings

d. Orientation +5 for vertical supports T 15 for remaining supports

, c. Size or load Capacity Kame size or load capacity or larger than indicated on design dravings.

_ f. Design and Assembly Same as design drawings Details ,

l V. Clearances j

a. Wall Penetration '

1/8" minimum

b. Directional Changes Visually ensure no evidence of contact l with adjacent items.

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1. Based on information developed and supplied by Bechtel

_ _ (References 7 6 8).

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NSP-37-031 Revision 0 FIGURE 3.2 NONCONFORMANCE REPORT I

SYSTEM NONCONFORMANCE NO.

DESCRIPTION OF NONCONFORMANCE:

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,l CORRECTIVE ACTION TAKEN:

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NSP-37-031 Revision a 4.0 REPORTING AND RESOLUTION OF DISCREPANCIES NUTECH was responsible for resolving all discrepancies , subj ec t to NSP review and approval. In resolving each identified dis-crepancy, the following approach was taken:

1. An engineering evaluation was made of the discrepancy to determine if it impaired the operability of the system. This evaluation was performed at two levels.

The first level consisted of applying engineering judg-ment to the discrepancies to obtain an immediate, i.e.,

within two (2) days, evaluation of the impact of the discrepancy on system operability. When required, a I second-level evaluation consisting of an analytical evaluation of the discrepancy was made. In some cases, this evaluation required the same degree of sophistica-tion as was utilized in the original seismic analyses.

However, most discrepancies did not warrant such a rigorous analysis technique.

I 2. Subsequently, an additional evaluation of discrepancy was made to determine if the piping system the still met the original design criteria described in the FSAR. Where it was determined by use of the original analyses that the as-built systems were adequate to meet the FSAR requirements, no further action was taken.

However, if the as-built conditions were judged to have I a potential for exceeding FSAR requirements, reanalysis of the piping system to the as-built condition and the original design requirements was accc,mplished.

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NSP-37-031 Revision 0 I In general, for those lines where reanalysis was deemed I necessary, a revised stress repor t ., and, where appropriate, drawings reflecting the as-built conditions will 'e issued o

to document the changes.

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I NSP-37-031 Revision 0 I 5.0

SUMMARY

OF DISCREPANCIES IDENTIFIED DURING THE PHASE J ACCESSIBLE PIPING INSPECTION I in the inspection are discussed The discrepancies identified below. These discrepancies can be categorized in one or more of the following categories.

I 5.1 Discrepancies Resolved by Engineering Judgment I These discrepancies are those that exceeded the tolerances specified in Table 3.2, but were judged to be of no significant consequence to operability or compliance with FSAR requirements, e.g., an as-built pipe run which is shorter than the as-analyzed length, whereby the analysis is judged to be conservative, since the shorter unsupported length would have lower stresses. The I

discrepancies in this category require no further action.

5.2 Discrepancies Requiring Further Analysis to Evaluate Operability These discrepancies required reanalysis rather than engineering judgement to ensure that an operability concern did not exist.

No line segments were in this category.

I 5.3 Discrepancies Requiring Further Analysis to Evaluate FSAR Compliance Discrepancies in this category are those which did not produce an operability concern, but did require reanalysis to verify that the original FSAR margins were maintained. Table 5.2 lists the I line designations with such discrepancies, the discrepancy or reason for reanalysis, and the results of the reanalysis. A total of 3 lines required reanalysis in this category.

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5.4 Discrepancies Identified During the Field Inspection During the field inspection of the accessible piping, a total of 15 conditions requiring repair were found to exist in the piping systems. Of the 15 conditions reported in the Phase 1 report I (Reference 9), 10 were associated with Phase 1 piping systems and 5 were associated with the Phase 2 accessible piping systems.

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M M M M M M M M M ' - M M TABLE 5,1 LINES REQUIRING REANALYSIS TO EVALUATE FSAR COMPLIANCE SYSTEM LINE DESIG REASON FOR REANALYSIS RESULTS OF REANALYSIS RHR TW14A-20HE Analyzed pipe segment lengths aMaxirum stress 18%

(Book 1) TW17-14HE not within specified tolerance.

TW15-14HE Missing seismic restraint. lofCvdeallowable.

TW27-20HE D82-3HE

- RHR TW21-3HE Analyzed pipe segment lengths Maximum stress 43%

(Book 2) not within specified tolerance. of Code allowable.

RHR TW23-12GE Snubber support (SS-33) not In progress (Book 3) analyzed in correct orientation.

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6.0 CONCLUSION

7 j An inspect. ion survey addressing the concerns of IE Bulletin 79-14 was conducted at the Monticello Nuclear Generating Plant in July, j

August and September of 1979 for the accessible Phase 2 piping systems. Results of that inspection reveal that, based on

] engineering judgement, no operability concerns exist, and for all 2

but three of the Phase 2 accessible piping segments, stresses a meet the original design requirements for the plant.

J For the three piping segments described above, a detailed analysis was performed to evaluate compliance with original design requirements. For two of the three lines, the detailed analysis has been completed and indicates stresses to be well within original design requirements. The analysis of the

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remaining pipe segment is in progress and will be completed by j October 31, 1979.

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7.0 REFERENCES

1. IE Bulletin 79-14, " Seismic Analysis for As-Built Safety-Related Piping Systems," Original Issue dated July 2, 1979, aad Revision 1, dated July 18, 1979.

] 2. Supplements to IE Bulletin 79-14, " Seismic Analysis for J As-Built Safety-Related Piping Systems," dated August

15.. 1979, and September 7, 1979.

3. "IE Bulletin 79-14, SAFETY-RELATED PIPING SYSTEMS, INSPECTION PLAN, MONTICELLO NUCLEAR GENERATING PLANT",

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NUTECH Report NSP-37-005, Revision 0, dated July 31, 1979,

4. "IE Bulletin 79-14, SAFETY-RELATED PIPING SYSTEMS,

INSPECTION PLAN, MONTICELLO NUCLEAR GENERATING PLANT",

NUTECH Report NSP-37-005, Revision 1, dated August 30, 1979,

5. MONTICELLO NUCLEAR GENERATING PLANT, MONTICELLO, FINAL SAFETY ANALYSIS REPORT, Northern States Power Company, Minneapolis, Minnesota.

6. Quality Assurance Audit on NSP Pipe and Fitting Data,

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performed by Nuclear Services Corporation in November 1970.

7. Letter from C. B. Hogg to D. Anthony, dated July 24, 1979; Subject, " Job 10040, Monticello Nuclear

__. Generating Plant Unit 1, Northern States Power Company, NRC IE Bulletin 79-14, As-Built Tolerances."

8. Letter from C. B. Hogg to D. Anthony, dated August 8, 7 1979; Subject, " Job 10040, Monticello Nuclear Generating 17 1145 079

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,NSP-37-031 Revision a Plant Unit 1, Northern States Power Company, NRC IE Bulletin 79-14, Revised As-Built Tolerances."

9. "IE Bulletin 79-14, SAFETY-RELATED PIPING SYSTEMS, PHASE 1 INSPECTION REPORT, MONTICELLO NUCLEAR GENERATING PLANT" NUTECH Report NSP-37-025, Revision 0, dated September 21, 1979.

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