ML19310A187
| ML19310A187 | |
| Person / Time | |
|---|---|
| Site: | Zion File:ZionSolutions icon.png |
| Issue date: | 04/23/1980 |
| From: | Shannon R COMMONWEALTH EDISON CO. |
| To: | |
| Shared Package | |
| ML19310A183 | List: |
| References | |
| NUDOCS 8006060242 | |
| Download: ML19310A187 (7) | |
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UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION BEFORE THE ATOMIC SAFETY AND LICENSING APPEAL BOARD f
IN THE MATTER OF
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)
COMMONWEALTH EDISON COMPANY
)
Docket Nos. 50-295
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50-304 (Zion Station Units 1 and 2)
)
)
Proposed Amendments to
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Increase Spent Fuel Storage
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Capacity (43 F.R.
30938)
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STATE OF ILLINOIS
)
) SS.
COUNTY OF C O O K
)
AFFIDAVIT OF ROBERT E.
SHANNON I,
ROBERT E.
SHANNON, of lawful age, being first duly sworn, upon my oath certify that the statements contained in the attached pages and accompanying exhibits are true and correct to the best of my knowledge and belief.
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Robert E. 'Shannon i
j SUBSCRIBED AND SWORN TO before me this l~ / day of April, 1980.
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\\ Notary Public My commission expires
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AFFIDAVIT OF ROBERT E.
SHANNON My name is Robert E. Shannon.
I hold a B.S.
in Metallurgical Engineering from Purdue University and an M.S.
in Materials Science from Northwestern University.
Since l
1973 I have been employed by Commonwealth Edison Company; since 1976 as the Inservice Inspection Coordinator at Zion Station.
As such, I will be responsible for coordinating and supervising the Zion Spent Fuel Pit corrosion surveillance program.
In the Zion spent fuel rack proceeding Commonwealth Edison made a commitment to carry out an intergranular stress corrosion cracking (IGSCC) surveillance program including annual visual and ultrasonic (UT) inspection of ten specimens containing weld geometries and material similar to those in the fuel racks.
This commitment is reflected in footnote 166 of the Licensing Board's Initial Decision.
The specific geometries of these specimens were not specified at the time of the Initial Decision.
However, Commonwealth Edison has now settled on specific representative specimens in preparation for installing the racks.
In reviewing these specimens, I have come to the conclusion that it would be preferable to substitute dye-penetrant (DP) testing for annual UT inspections as initially proposed.
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o The ICSCC speciments will be eight part-length I
two-tube clusters substantially similar to the one in the l
l attached diagram.
The boxes in the diagram are only the outer sheaths of two storage tubes, rather than complete tube cross-sections.
These samples will not contain the stainless steel inner sheath or boral since those elements are not structurally important.
The drawing is inacct. rate j
in one respect in that the joining strips will run the full length of most sample clusters, rather than the approxi-mately 10 inches shown in the diagram.
The seam welde and fillet welds on each cluster sample are exactly the same as those in the tubes and joining strips in the racks.
These part-length cluster samples were made from the same materials as the racks.
They were manufactured in the following steps:
first the outer sheath of two full-length tubes was
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formed, then the full-penetration seam welds were made on each tube, then the tubes were joined into a cluster with the joining strips using fillet welds, and then the resulting full-length two tube cluster was cut up into the final part-length cluster samples.
In addition to the eight part-length cluster samples, Commonwealth Edison will put two full-length tube clusters in the pool.
One will consist of three tubes, the other will consist of two tubes.
These clusters will be made up of.
complete tubes with boral inside, similar to the tubes and clusters in the racks.
The only differences are that the tubes used for these cluster samples are rejects from the manufacturing program.
Some were rejected because they have excessively thick (.15" vs..12 5 ")
fillet welding in some areas, and others contain boral plates which were rejected because they had insufficient boron-ten loading.
These defects will be marked for identification so they don't confuse or interfere with the validity of the surveillance program.
I believe that the weld geometries in these specimens, i
while representative of the new spent fuel racks, may lead to UT results which are inconclusive in detecting the onset of IGSCC.
Specifically, the somewhat complex geometry of the fillet-type welds may cause misleading ultrasonic reflectors, possibly masking indications of flaws or giving erroneous indications where no flaws exist.
Also, current ultrasonic techniques are not readily adaptable to thin plate material due to "near field" ultrasound beam Lehavior and therefore would be insensitive to IGSCC in the.105 inch thick seam welds.
Moreover, the use of dye penetrant examinations is an even more reliable technique for the detection of the small, tight surface cracking, expected from IGSCC.
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1 I therefore recommend that PT examinations in l
accordance with attached Commonwealth Edison Procedure NDT-D (including App. A and Addendum Dl), or its equivalent, be substituted for the UT examination technique in the Zion spent fuel pit corrosion surveillance program.
I point out that this CECO procedure is written in accordance with the l
ASME Boiler and Pressure Vessel Codes and dictates an acceptance criteria that requires the reporting of all linear and crack-like indications.
The procedure also requires a post examination cleaning of the tested components with low halogen - low sulfur solvent to assure containments are not introduced to the materials or into the spent fuel pool i
following testing.
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4 des 78 Ddte The undersigned, representing Zion Station's Authorized fluclear Inspector, has witnessed the follow-ing procedure as part of the Special Process Procedure Manual and requirements of the :' ion Station Quality Assurance Manual.
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.c Procesbs Witness - Authorized Nuclear Inso.
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