ML20086R757
| ML20086R757 | |
| Person / Time | |
|---|---|
| Site: | Byron  |
| Issue date: | 02/17/1984 |
| From: | Tramm T COMMONWEALTH EDISON CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8403010130 | |
| Download: ML20086R757 (5) | |
Text
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,/ Chicago, Illinois 60690 February 17, 1984 Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555
Subject:
Byron Generating Station Unit 1 Preservice Inspection Program Plan NRC Docket No. 50-454
Reference:
(a) March 1, 1983 letter from T. R. Tramm to H. R. Denton (b) August 26, 1983 letter from T. R, Tramm to H. R. Denton (c) December 6, 1983 letter from T. R. Tramm x
I to H. R. Denton 1
(d) December 14, 1983 letter frem T. R. Tramm l
to H. R. Denton l.
Dear Mr.- Denton:
This letter will revise and supp]ement the Byron 1 Preservice Inspection Program (PSI) Plan which was submitted in reference (a) through (d).
In response to comments and suggestions from the NRC staff several Notes and Relief Requests have been revised.
Additional informatinn-is also provded regarding the examination of cast stainless steel components.
In general, the notes incorporated into the Byron 1 PSI Program are documentation of the manner in which the Section XI requirements will be satisfied at Byron Station.
They do not
.usually involve deviations from ASME Section XI requirements which would necessitate NRC approval of relief from the provisions of 10 CFR 50.553.
There are, nowever, two notes in the Byron PSI Program Plan for which NRC approval is requested.
Because nonconformance reports have been written for the items discussed in Notes 5, 8,
and 11, it is necessary that NRC concurrence be obtained on tnose items.
The main steam nozzle inner i
radii-examination discussed in Note 8 has been incorporated into l
relief request NR-14, which covers similar examinations in other
. systems.
Aporoval of Notes 5 and 11 is therefore all that is needed.
Revised relief request NR-14 (Rev. 1) and Note 8 (Rev. 1) are enclosed.
Note that the nozzle inner radii examinations of the residual heat removal system heat exchanger have been added to NR-14.
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!Mr.-.H. R.-Denton February 17, 1984-Dage 2
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L Please address questions regarding this matter to this 1
Our signed. original-and fifteen copies of this letter and the attachments are provided for NRC review.
Very truly yours,
/kt 4"
T. R. Tramm Nuclear Licensing 'dministrator Attachment q-8175N
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.T NR-14 i
Rev-1 RELIEF REQUEST NR-14 1.
SYSTEM:- Steam Generator Vessel (Secondary Side) Nozzles Residual deat Exchanger Nozzles 2.
NUlBER OF 1T815: 8 Component Number Nozzle Number lac 01BA SGN-02,03 1RC01BB SGM-02,G3 lacolBC SGM-02.03 1RC01ED SGN-02,03 1RH02AB RHXN-01,02 3.
ASME CODE CLASS: 2 4.
AalE CQDE 38CTION XI RBQUIREMENTS: Table IWC-2500-1, Examination Category C-B, Item C2.20 requires surface and volumetric examination of the regions described in Figure IWC-2500-4 for nozzles in vessels over 1/2 in. in nominal thickness. Figure IWC-2500-4 requires volumetric examination of the inner radil on nozzles over 12 in. nominal pipe size.
In addition, mramination Category C-H, Item C7.10 requires a system leakagt test, INC-5221, each inspection period for all pressure vessel
. pressure retaining components.
Subarticle INC-2200 "Preservice Inspection" states that:
- a. -
All examinaticns required by this Article for those components initially selected for examination in accordance with Inspection Program A or Inspection Program B and not exempted from inservice examination by IWC-1220 shall be completed prior to initial plant startup.
5.
BASIS FOR RELIEF: Ths no zles listed above contain inherent geometric constraints which limit tha ability to perform meaningful ultrasonic examinations. The main steam nozzles (SGN-03's) have an internal multiple venturi type flow restrictor, see Attachment 1.
This design does not have a nozzle inner radii as described in Figure IWC-2500-4. This nozzle has seven individual inner radii, corresponding to each venturi, none of which could be examined by ultrasenic examination. The main feedwater nozzles (SGN-02's) also have an internal multiple venturi type flow restrictor but have a thermal sleeve in addition, see Attachment 2.
This design could not be examined due to the geometry of the nozzles internal design.
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E-14 Rev. 1 2
The Residual Heat Removal Heat Exchanger aozzles are 14 in. dia. and approximately 3/8 in. in nominal wall thickness. The Residual Heat Remval Heat Exchanger is approximately 7/8 in. nominal wall thickness.
In an attempt to develop a technique to locate flaws in the nozzle inner radii' area, a mockup was used with little success. The only notch which was detectable was the deepest one which penetrated the cladding and extended to a depth of approximately 5/16 in. into the carbon steel.
i Although the nozzles listed above are not internally clad, and the mockup was, it was determined that this mockup was representative of the required inspection.
- 6.
41.TERNkTE TEST MTHOD: Ultrasonic examination of the above listed nozzle inner redii is not practicable and the inner radii is not accessable to direct contact for surface examination or even remote visual examination.
However, these nozzles have been examined at the point of attachment to the vessel by radiography per MIM Section III, and by ultrasonic examination per ASME Section XI.
In addition, a system hydrostatic test, et 1253 of the design pressure, has been performed in accordance with ASME Section III and a system leakage test, at 100% of the system nominal operating pressure, will be performed each inspection period in accordance with ASM Extion XI.
7.
JUSTIFICATION: The above listed main steam and main feedwater nozzles are designed with multiple venturi type flow restrictors to limit flow during a Main Steam line or Main Feedupter line break. This design.thus enhances the plant's inherent level of safety but does not allow meaningful ultrasonic examination of the nozzles inner radii. however, the increased safety margin afforded by these nozzles makes them a
. desireable part of plant design. In performing the ASM Section III inspections, the ASME Section XI ultrasonic examination, and the inservice leakage test, an adequate level of structural integrity for these nozzlec is assu:ed for plant operation.
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