ML20235U886
| ML20235U886 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 09/30/1987 |
| From: | Lippold W BALTIMORE GAS & ELECTRIC CO. |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| NUDOCS 8710140298 | |
| Download: ML20235U886 (5) | |
Text
.
BALTIM O RE.
GAS'AND ELECTRIC r
e CHARLES CENTER P.O. BOX 1476. BALTIMORE, MARYLAND 21203
- W. JAMES LIPPOLD MANAGER NUCLEAn ENGINEsntNo SEnveCES DEPARTMENT September 30, 1987 i
U. S. Nuclear Regulatory Commission Washington,' DC 20555 ATTENTION:
- Document Control Desk
SUBJECT:
Calvert Cliffs Nuclear Power Plant Unit Nos.1 & 2; Docket Nos. 50-317 & 50-318 Commercial Ouality Mechanical Fastener Evaluation
REFERENCE:
(a) Letter from Mr. J. A. Tiernan (BG&E) to NRC Document Control Desk, dated May 11, 1987, Use of Mechanical Parts Purchased Commercial Quality in ASME Section XI Class I, 2 and 3 Systems (b) Teleconference between Mr.
A.
R.
Thornton (BG&E) and Mr. L. E. Tripp (NRC), on September 15, 1987, same subject Gentlemen:
In ' Reference - (a) we stated our intentions to remove, test and evaluate specific mechanical fasteners in ASME Section XI Code Class Systems. Since that time, we have worked steadily and committed considerable resources to complete the testing and evaluation in ' a timely manner. This letter provides the results of our evaluation and the actions we have taken and plan to take as discussed in ' Reference (b).
Evaluation Results i
We have tested individually 1539 fastener components or pieces, where a piece is a i
stud, nut or bolt. Each has received a surface examination, a hardness test and a chemical analysis. Approximately 150 pieces we removed from the plant which we do not plan to test. Of these, 50 pieces were misplaced or mislabeled when they were removed j
from the plant.. Approximately 100 pieces cannot be decontaminated without the expenditure of significant additional resources and radiation exposure. We do not i
believe the information we would receive from testing those 100 pieces would justify l
the resources and exposures that would be required. We also feel the remaining 1539 l
fasteners are representative of those not tested, j
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i 8710140298 870930 R
0 ADDCK 05000317 4
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r Document Control Desk
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September 30, 1987 Page 2 l
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All 1539 pieces have been compared to the applicable chemistry and hardness material j
specifications to determine whether they were adequate to have performed their design
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function. Initially, 399 pieces yielded test results that were out of specification.
I The chemical composition for 174 of the 399 pieces differed sliRhtly from the material I
requirements, but the hardness was within specification. For these it was clear that the pieces were of the correct material and that the critical property - strength as determined from hardness measurements - was adequate. We therefore determined that j
these were adequate to have performed their design function.
1 A number of other pieces had the chemical compositions within the specification range or only slightly out of range, but the hardness was just beyond the specified range.
Based upon engineering judgment, we determined that fasteners with hardness within 10%
l of the specified strength were adequate. This meant reducing the minimum hardness for j
B7 studs from 26 IIRC to 23 IIRC and,2H nuts from 24 HRC to 22 liRC. We found 40 pieces l
were acceptable with this criteria. This engineering judgment was substantiated by the evaluation performed on the remaining 185 pieces.
l The remaining 185 pieces come from 26 different locations within the plant. An evaluation specific to each location was performed to determine if the pieces had adequate strength. We analyzed each of these 185 pieces in a manner consistent with the class of each item and found that in all cases the actual material properties were adequate to ensure the structural integrity of the system. Data relating to these results are listed in Attachment 1.
Conclusion From the above, we conclude that although a significant number of pieces did not meet their originally specified requirements, all would have functioned to ensure the structural integrity of their system. Because our testing and evaluations of the 1539 l
fasteners yielded adequate results, we are confident that the use of commercial quality fasteners in our Class 1, 2 and 3 systems never posed an unreviewed safety question.
Immediate Preventive Actions in early June 1987, BG&E initiated a comprehensive investigation to identify the root cause of the mechanical fastener traceability situation that had arisen at Calvert
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Cliffs. Several issues were identified for which corrective action was felt to be l
prudent, but the primary causes were found to be (1) inadequate awareness of the material quality and traceability requirements for mechanical fasteners used in ti e I
maintenance of ASME Class I, 2 and 3 systems, and (2) the absence of formal casy-to-use l
documentation to assist our personnel in the identification of code boundaries during maintenance planning activities.
To correct these problems, maintenance personnel and quality control inspectors were given special training and instruction on the code requirements that apply to fasteners in Class 1, 2 and 3 systems. In addition, formal guidance documents were provided to j
maintenance personnel to facilitate the identification of code boundaries during
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routine maintenance planning activities.
These actions ensure that present-day i
maintenance activities affecting Class 1,
2 or 3 systems are identified as such when l
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h
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Document Control Desk i
September 30, 1987 d
Page 3 f
1 the maintenance order is written and that appropriate replacement fastener materials
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are specified accordingly on the maintenance order form. To monitor the performance of i
individual maintenance work ' activities in the field, quality control inspections are 1
conducted in accordance with existing QA program requirements.
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Suonlemental Actions l
The 'immediate actions described above provide reasonable assurance that all applicable I
material quality and traceability standards will be maintained in current and future l
maintenance activities at Calvert Cliffs.
Nonetheless, a number of supplemental j
actions are presently under consideration which would simplify and further improve i
procedures for controlling the procurement, storage, and use of mechanical fasteners.
The objective of these supplemental initiatives is to make the overall maintenance process more effective and thereby less prone to error. Examples of these initiatives
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include:
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o Replacement of the commercial quality (72/78 series) fastener stock I
inventory with Nuclear Class i fasteners; o
implementation of a fastener standardization program for all fastener applications in the plant; o
Development of a comprehensive computer database for use by engineers, maintenance planners, and purchasing personnel in identifying specific code requirements and allowable procurement methods for each piece of mechanical equipment ; and o
Upgrade of the material descriptions in the material management system (MMS) computer database to improve consistency in stock item descriptions and to provide more flexibility in the types of computer sorts that can be performed.
Should you have further questions regarding this matter, we will be pleased to discuss them with you.
Very truly yours, 0
WJL/SRC/dtm Attachment cc:
D. A. Brune, Esquire J. E.
Silberg, Esquire R. A.Capra, NRC S. A.McNeil, NRC V' T. Russell, NRC T. Foley/D. C. Trimble, NRC l
i j
7 ATTACHMENT I L
MCQ FASTENER STRENGTII EVALUATION
~ MO#
Piece #
= Desc.-
' Spec.
Hardness Strength (KSi)
. Comment I
- 590 A -
1 S
B7 22 HRC 112 Chemistry OK 2
Forging Lap 494A 6
'N 2H I
651A 6
N 2H 10.3 HRC 90 Chemistry OK 564A' l-7 S
B7 90 HRB.
89 Stainless Steel 3 564A 14,15,16-N 2H 90 HRB 89 Stainless Steel 4
'781A 1-12
.B SAE 2.5 HRC 80
' Low Carbon Steel Grade 5 781'A '
15-20 B
SAE 5.0 HRC 86 Low Carbon Steel Grade 5 1781A-21-40 N
2H 5.4 HRC 86 Low Carbon Steel 667A 21-52 N
2H 88 HRB 85 Low Carbon Steel' Forging lap 5988 6
N 2H 585A 9-24 N
2H 10 HRC 90 Low Carbon Steel 607A 3
B.
B7 88 HRB 85 Low Carbon Steel 607A 4
B B7 80 HRB 72 Low Carbon Steel 607A 5
N 2H 72.7 IIRB 65 Low Carbon Steel l
646B 3
N 2H 20 HRC 108 Chemistry OK 302A 21 N
2H 20 HRC 108 Chemistry OK 850A 9-24 N
2H 88 HRB 89 Low Carbon Steel
(#22) 797A 2,4 S
B7 22 HRC 112 Chemistry OK 646A' 3
S B7 75 HRB 68 Low Carbon Steel 850A 9,10,12 N
2H 10.3 HRB 90 Low Carbon Steel (021) 14-23 I
670A 2
N 211 15 HRC 94 Low Carbon Steel l
1 i'
4-*
~ ATTACHMENT I l
'I MCQFASTENER STRENGTH EVALUATION i
c 1
. MO'#.
Piece # -
Desc.
Spec.
Hardness Strength (KSi)
Comment l
l 761A 1,2,4,5 S
B7 90 HRB 89 Low Carbon Steel W
761A-
-6 S'
B7.
22 HRC 112 Chemistry OK 761A 10-16,19-21 N
2H 92 HRB 93 Low Carbon Steel
-718A 1
B B7 16.5 HRC 95 Chemistry OK I
l 588A-4 B
B7 71.4 HRB 62 Low Carbon Steel 1
l 588A 8
N 2H 86 HRB 81 Low Carbon Steel 1
771A.
17.
S B7 21HRC 110 Chemistry OK 601A' 5
- S B7 21HRC 110 Carbon Slightly Low 850A 4
S B7 21HRC 110 Chemistry OK
(#23) 850A 9-24 N
2H 90 HRB 89 Low Carbon Steel 837A 4
B SAE 19.5 HRC 106 Chemistry OK Grade 5 837A 10 N
2H 90 HRB 89 Low Carbon Steel Forging Lap 768A 1
B A325 696A 4.5,10-13 N
2H 70 HRB 62 StainlessSteel Forging Lap
.757A
.21 N
2H l
N - Nut i
' S - Stud B - Bolt I
Chemical composition was in specification.
2 Indications that were found by NDE.
3. Piece ~ was composed of stainless steel.
4 Piece was composed of Low Carbon Steel. L
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