ML19338E642

Responds to NRC 800731 Ltr Re Violations Noted in IE Insp Rept 50-369/80-18.Corrective Actions:New Procedures Initiated for Insp of Pipe Supports & Rusty Weld Rods Have Been Properly Disposed

ML19338E642
Person / Time
Site:	McGuire
Issue date:	09/05/1980
From:	Parker W DUKE POWER CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML17095A604	List: ML19338E642 ML19338E648
References
NUDOCS 8010030491
Download: ML19338E642 (19)

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.,,, 7, Duxe POWER COMPANY' 'r/

Powtu Dunmano 422 SOUTH CHUNCH STREET, CHAMwTTE, N. C. asa4a .

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. \L wiwaw ca. mannen,sn. September 5, 1980 VeCr Passiotat Tettre ont:Amra704 Strans Pacoucreow 373-40 e 3 Mr. James P. O'Reilly, Director U. S. Nuclear Regulatory Commission Region II l

101 Marietta Street, Suite 3100

Atlanta, Georgia 30303 I

Subject:

McGuire Nuclear Station

., Docket No. 50-369 i

Reference:

RII:WPA 50-369/80-18

Dear Mr. O'Reilly:

Please find atts.ched our response to the items of noncompifance in Appendix A of the subject report. In addition, find attached a discus.sion on the two items of c terrn identified in your July 31, 1980 letter which transmitted the subject inspection eport.

Ver truly yours,

_ _ _ lb. CLt William O. Parker, Jr.

LJB:scs Attachment OFFICI AL COPY 0010080 sjgy . - - .

IE Inspection Report 50-369/80-18 Item A.1 Pipe support 1-NI-H210 had been deleted by Design Eugineering after i Initial installation. The final walk down inspection of a piping system for adequate supports is performed by math model (analysis segment). This particular problem was the result of inadequate instructions in defining the scope of pipe to be inspected for an Individual math model. Detailed instructions have been prepared in Construction Procedure 809 A review of drawings used for previous '

I inspections is underway. This review and any required reinspections are scheduled for completion by October 6, 1980. Future inspection i will be based on the new procedure. The particular support and over-

! all_ situation are described in Nonconformance item Report #11,409 1

Support 1-Nl-H210 was removed and reinspection accomplished by i September 3, 1980.

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IE Inspection Report 50-369/80-18 Item A.2 The referenced pipe support, 1-MCA-HV-HI, is a boxed configuration composed of structural angles. The horizontal members are 3" x 3" x 3/8" angles. One of these members was Installed at a slight angle relative to the other member. This condition gives the appearance that the support is bent. Since no erection tolerance was given on the_ support drawing for these members, the drawing indicates that they should be installed exactly perpendicular to the base plate. One angle is approximately 3 off horizontal. Design Engineering has determined that the critical dimensions of the support are correct and the support is adequate. It was concluded that this item did not represent a generic problem in the pipe support program.

As a result of the NRC concern, support l-MCA-NV-HI was identified on Noncongorming item Report 11,666 and was resolved on September 3, 1980, as stated above.

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IE Inspection Report 50-369/80-18 Item A.3

, The particular anchor in question is not acceptable. The situation as discovered by the NRC inspector was documented on Nonconforming item Report #11,667 The resolution to this NCl includes corrective action on the subject anchor and an audit of previously accepted anchors _ by the subject inspector. Both of these activities will be complete by September 16, 1980.

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1 IE Inspection Report 50-369/80-18 2

item B This item states that weld rods were found on three different supports.

The rusty ^ condition of the rods indicated that they were ,inadverently left on the supports during their erection. The rods have been properly

' disposed. We continue to reinforce compliance to requirements to control filler material. Both craft supervision and Quality Assurance personnel

! continually survey work areas to place proper emphasis on material con-

, trol. These welding. rods were in obscure places and would not normally be j seen. We conclude that this is an isolated case and no program charges

are necessary.-

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.- Response to-lE Inspection Report 50-369/80-18 Additional items of Concern (#1)

RESPONSE

A meeting was held on August 8,1980 with your office regarding this subject.

It was agreed that a supplemental response to IE Bulletin 79-02 would be sub-mitted which supports our design practice on a system by system basis. It is felt that this. response will adequately address your concerns in this area.

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Response to IE Inspection Report 50-369/80-18 Additional items of Concern (#2)

Background Discussion:

In May, 1979, Duke Power Company reported to the NRC that there was reason to believe that there were inadequacies in our inspection program or, supports; and therefore, we would be , a a reinspection program on all safety-related pipe supports in McGuire Unit #1. (Ref.

50.55e as described in IE Report Number 369/79-22 Item 2). When start-Ing this reinspection program in June 1979, Duke Power Company set forth the goal of confirming the adequacy of the supports to function as designed.

Following is a summary of the reinspection program at McGuire:

f Quallfled engineers from Duke's Design Engineering Depart-ment marked up each sketch with all applicable tolerances.

These engineers compared the marked-up controlled copy of the support sketch against the erected support. This comparison by the qualified engineer was not considered a QC acceptance inspection.

Af ter the engineer had completed this comparison, a QC inspec-tor used the marked-up sketch and QA Inspection instruction Form H-15E for a detailed erection inspection. There are between

, 50 and 80 individual inspection points on a typical support.

Specifics:

1. As discussed in item #2 (Ril:WPA, 50-369/80-18), Duke reinspected 214 pipe supports in connection with corrective actions concerning the termination of ten QC inspectors. During this reinspection, approx-imately 200 additional discrepancies were discovered on 92 pipe supports, All of these discrepancies identified were subsequently evaluated by Duke and found to be acceptable. It is pointed out that there were between 10,000 and 17,000 Inspection po!nts on these 214 supports. The additional discrepancies represent between 1.3% and 2.2% of the total Inspection points.

2. In the July 15, 1980 meeting with the NRC, Duke agreed to the following commitments with actions taken as noted:

4 Commitments f..lon

a. Increase QA surveillance Effective in July, QA surveillance frequency to monthly. was increased to monthly,

b. Conduct engineering review 30 additional supports were re-of erected condition of viewed and details presented additional highly stressed below in Concluslots, #1.

supports.

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. Commitment Actions

c. Demonstrate applicability of Duke has completed a review of the reinspection of 214 hangers these 214 hangers. During the to McGuire hanger population. engineering review, 3 additional supports were reviewed bringing the total to 217. Details are presented in Conclusions, #2,

1. 3, #4, #5, and #6.

Conclusions:

This sample of 217 supports does adequately represent the total population of pipe supports at McGuire, based on consideration of the characteristics as discussed in paragraphs one through six below.

1. Stress Concentrations (Attachment A) 12% of these supports have high stress levels. As discussed in the July 15 meeting, Duke agreed to have qualified Design Engineers to review the erected condition of some additional highly stressed supports (see Attachment B). In screening more than 2,000 supports, only thirty (30) highly stressed supports were found. This indicates that highly stressed supports are somewhat rare, although this screen was not statistically designed to establish this conclusion. All 30 of the additional highly stressed supports were found to be structurally adequate and capable of functioning as designed.

2. Different inspectors (Attachnent C) 214 (of the 217) supports were inspected by 15 different inspectors (10 terminated inspectors and 5 control group inspectors).

The results indicate that there is little significant difference between the work effectiveness of Individual inspectors or the two groups. The two inspectors with the tota! number of discrepant supports higher than the average (one with 10 and one with 9) were again reviewed for type and number of discrepancies. Although buth were higher than average, the vast majority of supports inspected l

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3 by them had less than three discrepancies. There was no significant difference in the type of discrepancy found among any of the inspectors.

3 Tine Frame of installation The large majority of Unit I pipe supports were erected in the pe riod 1976 - 1980. This sample is representative, with most of the support erection taking place in 1978 (35%) and 1979 (37%).

4. Different Size Lines and Systems The f ollowing is a comparison of the pipe size associated with both the 217 support audit and the ASME systems installed in Unit #1.

Size of Pipe ASME installed Size of Pipe (Class A, B, & C) (Total Plant) (217 Support Sample)

$ 2" 54.5% 48.6%

2 1/2" - 6" 31.4% 33 8%

8" - 12" 10.6% 11.1%

>>12" 3 3% 6.5%

The 217 supports include an appropriate sample of pipe sizs. ,

The systems represented account for all the major safety related systems except Main Steam. The majority of Main Steam system supports are being revised and will be reinspected upon completion.

5 Various Types of Supports (Attachment A)

All types of supports are represented in the sample as Indicated in Attachmen A, with the rajority of the sample being rigid restraints.

6. Type of Discrepancies (Attachment D)

This summary represents the types of inspection items identified during the inspection program. Each item was evaluated by Design Engineering and none was found to be structurally significant.

As pointed out in the previous six items, these 217 supports are represent-ative of the family of 15,000 safety related supports at McGuire. This sample was not intended to be a scientifically designed statistical cross section, but the generic factors discussed indicate that this is an appropriately representative population.

Based on the careful and conservative inspection of pipe supports, Duke is confident that the pipe support system will function as designed.

Our analysis of the 217 pipe supports described above provides additional confirmation of this position.

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ATTACHMENT A PIPE SUPPORT / RESTRAINT CATEGORIZATION FOR SELECTED SUPPORT / RESTRAINTS (217) 1.0 Introduction and Summary The Design Engineering Department has reviewed and cate-gorized the maximum calculated stress level for each of the 217 support / restraints. Calculations for each support /

restraint were reviewed and the critical item was cate-gorized as having Low, Average, or High stress as compared to the allowable value. For members and welds, calculated stresses below approximately 50 percent of the allowable were considered Low, from approximately 50 to 80 percent, Average, and above 80 percent, High. For bolt interaction, below 0.60 was Low, 0.60 to 0.85 was Average, and 0. 85 to 1.00 was High.

In addition to categorization by stress level, the type of support / restraint was identified and the pipe line size was recorded.

2.0 Results and Conclusions Results for all items were reviewed and are tabulated Ls follows:

Support / Restraint Stress Level Low Average High Total Rigorous 74 38 20 132 Alternate 60 20 5 85 Total 134 58 25 217 (61%) (27%) (12%) (100%)

High Stress Item Number of Support / Restraints Member 84 (39%)

Weld 24 (11%)

Bolts 96 (44%)

Combination 13 ( 6%)

Total 217 (100%)

Based on categorization by support / restraint type, the follow-ing summary can be derived:

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Attachment A Pcga 2 Support / Restraint Type Number of Support / Restraints Rigid Support / Restraint 197 (90. 8%)

Sinubber Restraint 10 ( 4.5%)

Spring Support 10 ( 4iS%)

Total 217 (100%)

Based on categorization by pipe size, the following summary can be derived:

pipe Size Number of Support / Restraints 2" and less 105 (48.6%)

2 " - 6" 73 (33.8%)

8" -

12" 24 (11.1%)

> 12" 14 ( 6.5%)

Valve Support 1 Total 217 (100%)

Reviewing the above summaries it is concluded that:

(1) Approximately two-thirds of the total support / restraints in the sample have low stress levels, one-fourth have average stress levels, and one-eighth have high stress levels. A higher percentage of Rigorous Analysis piping support / restraints have high stress (15%) than do Alternate Analysis piping support / restraint (6%). Although this sample does not necessarily represent a purely random sample from the Unit 1 plant at large, these trends are those which would be expected.

(2) The most typically highly stressed items in a given support /

restraint are the members (39% of cases) and the bolts (expansion anchors) (44% of the caces). The sum of these two itens represents 83% of all support / restraints in the sample. As noted in the above summary, 6-percent of the time the most highly stressed items were a combination of items (two items were equally highly stressed). In most of these cases, the combinaticn is bolts c,.d members, hence the expected percentage of case.? where bolts and members are the most highly stressed items is closer to 90% than the above noted 83%.

(3) The majority of support / restraints in the sample are rigid restraints (90. 8%) compared to snubbers (4.6%) and spring supports (4.6%). Rigid support / restraints include simple vertical supports (gravity), vertical 2-way restraints, vertical / horizontal 2-way restraints, and vertical / horizontal /

axial 3-way restraints. Based on a known count of snubbers in Unit 1, the sample population is biased in favor of rigid restraints. Snubbers comprise approximately 8-percent of

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~ Attcchment A paga 3 the total Unit 1 support / restraints.

(4) The majority of pipe sizes represented 'in the sample is 6-inch OD and less. This compares favorably with the majority of.-the safety related pipe at McGuire.

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ATTACHMENT B STRUCTURAL ADEQUACY EVALUATION OF THIRTY (30) HIGHLY STRESSED SUPPORT / RESTRAINTS The Design Engineering Department performed a structural adequacy evaluation on thirty (30) highly stress support / restraints. These support / restraints were selected by screening support / restraints in selected, safety-related pipe stress math models. In order to identify thirty (30) support / restraints that were highly stressed, over 100 math models which contained over 2000 support / restraints had to be reviewed. This indicated that highly stressed support /

restraints are somewhat rare, although this screen was not statis-tically designed to establish that conclusion. The screen was designed to identify support / restraints that are safety-related and are complete in erection and inspection. It was also directed to obtain a mix of support / restraints in Rigorous versus Alternate piping analysis math models and in Reactor versus Auxiliary Build-ing which approximates that for the total pupulation of safety-related support / restraints. These statistics are as follows:

TOTAL SAMPLE CRITERIA POPULATION POPULATION NSR Total 15,276 (100%) 30 (100%)

Support / Restraints NSR - R. Bldg. 4,810 (31%) 6 (20%)

NSR - A. Bldg. 10,466 (69%) 24 (80%)

NSR - Rigorous 8,763 (57%) 24 (80%)

NSR - Alternate 6,513 (43%) 6 (20%)

In determining whether a support / restraint was highly stressed, member specified.

stresses and connections were considered for design loads No effort was applied ir. removing conservatisms (such as actual concrete strength, hand calculation methods, etc. ) which existed. For each selected support / restraint, the most highly stressed item was identified.

Design Engineering Department personnel were utilized to inspect the installed support / restraints in the plant and evaluate struc-tural adequacy. With a knowledge of the most highly stressed items, engineers evaluated the installed condition in general and in the hfgnly stressed area in particular.

Results of the evaluation are shown in Table B-1. It was concluded that all thirty (30) support / restraints are structurally adequate.

TABLE B-1 -

STRUCTURAL ADEQUACY EVALVATION

SUMMARY

SHEET 1 0F 2 ,

SUPPORT / RESTRAINT PIPE STRESS PLANT HIGilLY STRESSED ITEM STRUCTURALLY ADEQUATE

,. NUMBER MATH MODEL BLDG. yg g IMCA-CA-H49 CAC A Base Plate: 0. 46"d 0.50" X IMCA-CF-H310 CFX A Bolt In te r. : 0 99 5 1.0 X f IMCA-CA-H376 CAM R Base Plate: 0.61" d .625" X 1 I 1MCA-KC-1332 KC-302 A Bolt Inter: 1.0 d 1.0 X

} I MC A- KC-1111 KC-303 A Bolt Inter: 1.0 6 1.0 X IMCA-KC-1317 KC-303 A Bolt Inter: 0.97 6 1.0 X 6

I MCA- KC-2239 KC-305/310 A Base Plate: 1.13 "d 1.25" X IMCA-KC-1056 KC-313 A W4 X 13: 13149 psi d 13800 psi X 1MCA-KC-1106 KC-315 A Bolt Inter: 0 97 6 1.0 X 1MCA-KD-73 KD-10 A Base Plate stress:12692 ptid13800 psi X 1MCA-KD-63 KD-14 A Bolt Inter: 1.00 d 1.0 X j IMCA-ND-1240 NB-301 A Membe r s t ress : 12031 psi e 13800 psi X l SMCA-NB-1256 NB-301 A Angle Stress: 11442 psi d 13800 psi X i

j 1MCA-KC-1018 KC-302 A Bolt In te r: 0.96 41.0 X

! 1MCR-NI-846 NI-15 R Bolt Inter: 0.99

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l- 1MCA-NM-734 NM-05 R Base Plate: 0.32"d 0.375" X 1MCA-NV-379 NVA A Member Stress:11308 psid12000 psi '

X

.lMCA-RN-1200 RN-302 A Bolt Inter: 0.99 d 1.0 X 1MCA-RN-2530 RN-302 A Base Plate: 0.72" d 0.75" X 1MCA-RN-2561 RN-312 A Base Plate: 0.50" d 0.50" X IMCA-CF-292 CFC A Bolt Inter: 0.94 4 1.0 X IMCR-NI-618 NI-01/02 R Bolt in te r: 0.885

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MC-1683-RN.25-R6 AA A' Bolt Inter: 0.98 d 1.0 X Plate 0.5" d 0.625"

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ATTACHMENT C DISTRIBUTION OF HANGER INSPECTIONS BY INSPECTOR NO. HANGERS GROUPED BY NO. OF DISCREPANCIES FOUND TOTAL

. TOTAL NUMBER OF NEW DISCREPANCIES FOUND No.OF lN S PECTOR$ HANGER HANGER $

INITIA LS WITH AUDITED I 2 3 4 5 6 7 8 9 13 WSOREPM W1 12 I I I I I 5 W2 14 3 1 2 1 7 i

63 /f 2 2 I I I 7 g4 /1 3 2 1 6 I

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67 12 5 1 6 g8 15 3 5 l i 10 l-l- W 9 18 4 3 I 8 i

C10 Il I 4 I 6 g11 16 1 3 1 1 6 i

Q12 12 3 I .

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@ l5 18 5 I I 2 9 TOTAL 214 39 30 T 2 5 3 4 0 I I 92 PERCENT 100 % 18.3 14 3. 3 .9 2. 3 ' l. 4 1. 9 0 .5 4 43,%

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TOTAL NO. OF DISCREPANCIES: 22I l

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ATTACHMENT D

SUMMARY

OF DISCP.EPANCIES

l. Materials

1) Thinner than Specified 2

-2) Thicker than Speci fled 4

3) Cannot Verify Thickness 6

4) Larger Section 1 13 II. Dimension

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1) Angle of Member 7

2) Dimension varies from written tolerance 24

3) Tolerance not given , ' 3 34 --- - _ _ __ .

Ill. Bearing

1) Gap behind Base Plate 3

2) Cannot check Bearing 2

3) Bearing not shown .2 7

IV. Welding

1) Undercut 22

2) Pinholes 1

3) Arc Strikes 1

4) Lack of fussion 1

5) Not enough Weld

- Length and Not all around 6

- Welded all around except legs 7

- Size (small areas) 8

6) Extra weld not specified 11

7) Different type weld 5

8) Weld Symbol not shown 1 63 V. Bolts and Bolting

1) Not ful.1 Nut 1

2) Loose nuts 2

3) Loose Jam nuls 8

4) Locking device different than specified 2 13 P

VI. Concrete Anchors

1) Spacing 2

2) Not perpendicular 5

3) Torque less than 70% 4

4) Dif ferent anchor installed 1 12 M N ND* 6 M **d h em 544ee gang w gm ,.mw, u,w g, ,g, g, _

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.'. ATTA.*HMENT D Paga 1 Vll. Gaps

1) Box or strap 1/64 1 1/32 4 1/16 2

2) Other Clearances 4

3) Foreign Material in gap 1

4) Shim installed, not shown 4 16 Vill. Bent or damaged

1) Plate 1

2) Wide flange (flange) 1

3) Piece of Conc. 1

4) Conc. Anch. hit 1 4

IX. Clerical

1) Drafting 5

2) Transferring Inform. 3 8

X. Discrepancies identified but are not valid (NOTE 1) 29 29 XI. Discrepancies " Walk - Thru"

- Hanger touching object (NOTE 2) 2 201 disc.

NOTE 1: The inspection program for McGuire Unit #1 is a program that requires the inspector to have all inspection information available on the sketch. If the inspector has a question aboit an inspection point, it is written as a discrepancy.

This accounts for X above.

NOTE 2: The " Final-Walk" inspection is designed to be an additional check for hanger interferences and other discrepancies. Most of V, most of fill, and all of XI would be discovered.

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. lE Inspection Report 50-369/80-18 ftem B.

This item states that weld rods were found on three different supports. The rusty condition of the rods indicated that they were inadverently lef t on the supports dur~ng their erection. The rods have been properly disposed. We continue to reinforce compliance to requirements to control filler material. Both craft supervision and Quality Assurance personnel continually survey work areas to place proper emphasis on material control. These welding rods were in obscure places and would not normally be seen. We conclude that this is an isolated case and no program changes are necessary.

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IE Inspection Report 50-369/80-18 Item A.1 Pipe support 1-NI-H210 had been deleted by Design Engineering after initial Installation. . The final walk down inspection of a piping system for adequate supports is performed by math model (analysis segment). This part!cular problem was the resul. of inadequate instructions in defining the scope of pipe to be inspected for an individual math model. Detailed instructions have been prepared in Construction Proceoure 809 A review of drawings used for previous inspections is underway. This review and any required reinspections are scheduled for cumpletion by October 6,1980. Future inspection will be based on the new procedure. The particular support and over-all situation are described in Nonconformance item Report #11,409 Suppors 1-NI-H210 was removed and reinspection accomplished by September 3, 1980.

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