ML20214W502
| ML20214W502 | |
| Person / Time | |
|---|---|
| Site: | 07109151 |
| Issue date: | 11/24/1986 |
| From: | Bush F LN TECHNOLOGIES CORP. (FORMERLY LONDON NUCLEAR SVCS |
| To: | |
| Shared Package | |
| ML19292G392 | List: |
| References | |
| 28150, 28448, WM-013, WM-13, NUDOCS 8612100255 | |
| Download: ML20214W502 (7) | |
Text
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TITLE GAMMA SCANNING OF LEAD SHIELDING FOR LN TYPE CASKS TECHNOLOGIES
.C O RPO A ATION I
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COPYRIGilT C 1986 BY LN TECliNOLOGIES CORPORATION ALL RIGHTS RESERVED.
NO PART OF THIS DOCUMENT MAY BE REPRO-DUCED OR TRANSMITTED IN ANY FORM OR BY ANY MEANS, ELECTRONIC OR MECHANICAL, INCLUDING P110TOCOPYING, RECORDING OR BY ANY
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INFORMATION STORAGE AND RETRIEVAL SYSTEM, WITHOUT PERMISSION IN WRITING FROM LN TECHNOLOGIES CORPORATION, EXCEPT FOR STRICTLY CONTROLLED DISTRIBUTION, FOR EVALUATION PURPOSES.
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OklGINATOR DATE CHECKED
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2 of 7 TABLE OF CONTENTS Page 1.0 PURPOSE 3
2.0 APPLICABILITY 3
3.0 DEFINITIONS 3
4.0 REFERENCES
AND APPLICABLE DOCUMENTS 3
5.0 PROCUREMENT PROJECT MANAGER 3
6.0 PERSONNEL QUALIFICATIONS 3
7.0 EQUIPMENT 4
8.0 CALIBRATION 4
9.0 PROCEDURE 4
10.0 ACCEPTANCE CRITERIA 5
11.0 DISTRIBUTION 6
Figure 1 7
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1.0 PURPOSE This generic test specification procedure states the minimum requirements for gamma scanning of lead shielding for LN Type casks.
The fabricator shall submit for approval detailed gamma scanning procedures.
2.0 APPLICABILITY f
This generic procedure is applicable to all radioactive shipment casks or radiation shields fabricated for and procured by LN Technologies.
3.0 DEFINITIONS None S
4.0 REFERENCES
AND APPLICABLE DOCUMENTS 4.1 AECU 2967, November 1954 4.2 ASNT Recommended Practice No. SNT-TC-1A, 1980 Edition 5.0 RESPONSIBILITIES Procurement Project Manager - shall inspect and approve all vendor submitted gamma scanning procedures against this test specification procedure.
6.0 PERSONNEL QUALIFICATIONS Personnel conducting gamma scanning shpil be familiar with the detailed procedures and shall be certified Level II or l
I Level III radiographers in accordance with SNT-TC-1A.
(Reference 4.2)
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p WM-013 F
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7.0 EQUIPMENT The gamma detector shall be a model E120 Eberline or equiva-lent with a pancake probe.
The gamma source shall be either IR 192 or Co60 of sufficient activity in curies to obtain reasonable readings.
The source strength will be dependent on the lead and steel thickness being scanned.
8.0 CALIBRATION A calibration plate will be prepared using defect free lead equal to the nominal lead thickness for the specific cask.
Steel equal to the nominal specified wall thickness will be placed on either side of the lead.
The lead shall be design-ed so that several 1/8" sections of lead can be removed or added to the calibration plate.
The calibration plate will be installed in a fixture in place of the secondary cover as shown in Figure 1.
The source is placed inside the cask at a distance from the plate equal to the inside radius of the cask.
The radiation detector is placed on top of the plate and radiation readings are taken with the meter set on the lowest scale.
The test is then re-peated modifying the lead thickness in increments of 0.125 inches plus and minus the nominal lead thickness.
At least five points will be measured and a plot of lead thickness vs detector readout is then plotted.
The maximum acceptable reading during the gamma scan shall"be 1.1 times the reading obtained from the nominal lead wall thickness or the extrapo-lated reading for.90 percent of the nominal lead wall thick-ness, whichever is less.
9.0 PROCEDURE l
I 9.1 Mark a 4-inch grid system on the cask and record the l
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grid system on paper as a permanent record.
9.2 Locate the radiation source along the centerline axis of the cask and position it at the midpoint of the plane of the top row of grid squares.
9.3 Take readings at each grid square on the outside of the cask in the plane of the source.
The probe will be in contact with the cask surface when the radiation readings are taken.
9.4 Lower the source along the centerline axis to the midpoint of the next row of grid squares and repeat step 9.3.
9 9.5 Repeat step 9.4 until the bottom row of grid squares have been monitored.
9.6 Position the source along the centerline of the cask at a height equal to one cask radius off the bottom.
9.7 Take and record readings every 12 inches around the bottom circumference of the cask.
9.8 Position the source along the centerline of the cask at a height equal to one cask radius from the top of the cask.
9.9 Take and record readings every 12 inches around the top circumference of the cask.
l) 9.10 Average and record the six highest readings obtained in step 9.7.
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9.11 Average and record the six highest readings obtained in' step 9.9.
10.0 ACCEPTANCE CRITERIA 10.1 The radiation reading at any point on the cask circumference shall not exceed the value determined in section 8.0, except as noted in steps 10.2 and 10.3 10.2 The rea dings obtained in step 9.7 shall not exceed 125 percent of the average reading calculated in step 9.10, and they shall not exceed 50 percent of the value determined in Section 8.0.
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10.3 The readings obtained in step 9.9 shall not exceed 125 percent of the average calculated in step 9.11, and they shall not exceed 50 percent of the value determined in Section 8.0.
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DISTRIBUTION Library (2 Copies)
RECO Engineering, Richmond, VA.
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7 of 7 FIGURE 1 PANCAKE PROBE l
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