ML19309F090
| ML19309F090 | |
| Person / Time | |
|---|---|
| Site: | Grand Gulf  |
| Issue date: | 04/04/1980 |
| From: | Dale L MISSISSIPPI POWER & LIGHT CO. |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| AECM-80-63, NUDOCS 8004280484 | |
| Download: ML19309F090 (4) | |
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MISSISSIPPI POWER & LIGHT COMPANY Helping Build Mississippi P. O. B O X 16 4 0, J A C K S O N, MIS SIS SI P PI 3 9 2 0 5
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- 33 anoouction orpantu rut April 4, 1980 Office of Inspection & Enforcement U. S. Nuclear Regulatory Commission Region II 101 Marietta St., N.W., Suite 3100 Atlanta, Georgia 30303 l
ATTENTION:
Mr. J. P. O'Reilly, Director
Dear Mr. O'Reilly:
SUBJECT:
Grand Gulf Nuclear Station Units 1 and 2 Docket Nos. 50-416/417 File 0272/0498/15525 PRD-80/02, Defective Elbow in Control Rod Drive Hydraulic System AECM-80/63 On February 27, 1980, Mississippi Power & Light Company notified Mr. M. J. Gouge of your office of a Potentially Reportable Deficiency (PRD) at the Grand Gulf Nuclear Station construction site. The de-ficiency concerns material flaws discovered in an elbow fitting in the Unit 1 Control Rod Drive Hydraulic System. This deficiency was previously brought to your attention in a report submitted to you, pursuant to 10CFR21, by the Bechtel subcontractor, Reactor Controls, Inc., dated February 21, 1980.
It is our determination that the elbow in question, as used in this application, would not have adversely affected plant safety. Thus, this matter is determined to be not reportable under 10CFR50.55(e).
This determination was reported to Mr. F. Cantrell of your office via telephone communication on March 28, 1980.
This letter confirms the telephone communication of March 28, 1930, with Mr. Cantrell. Based on our determination of non-reportability within thirty (30) days of initial notification, a written report is 3()/9 not required. The attached report on PRD-80/02 is provided for infor-gg
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OFFICIAL COP [
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Member Middle South Utilities System 9
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Mississippi POWER & LIG'HT COMPANY Office of Inspection & Enforcement U. S. Nuclear Regulatory Commission Page two - AECM-80/63 mation purposes and is submitted during the week of March 31, 1980, as requested by Mr. Cantrell in the above referenced communication.
Yours truly,
. Dale
[ Nuclear Project Manager JGC/JDR:ts Attachment cc:
Mr. N. L. Stampley Mr. R. B. McGehee Mr. Victor Stello, Jr., Director Division of Inspection & Enforcement U. S. Nuclear Regulatory Commission Washington, D. C.
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Attachment to AECM-80/63 PRD-80/02 l
I.
Description Reactor Controls, Inc., a Bechtel subcontractor, detected material
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flaws in a fitting being idstalled in the Control Rod Drive (CRD) system. The flaws consisted of two linear indications on a 9" 900 carbon steel elbow and were discovered during liquid penetrant examinations of fitting welds. The fitting, Heat Code ID-M468, was manufactured by Capitol Manufacturing Company.
Reactor Controls, Inc., submitted a report, dated February 21, 1980, on this deficiency to the NRC pursuant to the requirements of 10CFR21.
II.
Safety Implications j
The elbow of concern is located in the 2" scram discharge volume drain line system, upstream of the discharge volume drain valve, designated C11-F011.
The essential safety function of the CRD system is to provide safe reactivity control via control rod positioning devices and to provide a sufficiently rapid control rod insertion, such that no fuel damage results from any abnormal operating transient.
The rapid insertion (scram) is effected in part by the venting of the volume above the CRD drive piston to a lower pressure plenum--
the scram discharge volume. Therefore, if a crack were to result from the observed discontinuity in this 2" elbow on the scram dis-charge volume drain line, the potential discharge would only serve to keep the scram discharge volume at a lower pressure, and thus, not interfere with scram performance. This elbow, along with all associated piping upstream of Cll-F0li is within containment.
With regard to reactivity control via control rod positioning, the scram discharge volume is drained and vented to atmosphere during normal operations by open vent and drain valves, Cll-F010 and C11-F0ll, respectively. Since the volume is normally vented, the hypothesized crack would not adversely affect the safe control of the plant during normal operations.
By the above discussion, it is our determination that the deficiency noted in this elbow, as used in this application, would not have adversely affected plant safety.
III. Corrective Actions The defective elbow will be replaced. It has been removed and returned to the manufacturer for analysis.
e The remaining fittings, of the same heat code and manufacturer, purchased by Reactor Controls, Inc., for use at Grand Gulf, have been dye-penetrant checked and found acceptable. Furthermore, an investigation has concluded that there is no additional material from the suspect heat code held at the Grand Gulf construction site by any supplier.
Details concerning this deficiency and the associated corrective actions are filed under Bechtel MCAR-GGNS-63.
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