ML20090K359

Interim Deficiency Rept 2 Re Calculated Max Temp for Main Feedwater Line Moment Guides Exceeding Design Basis Limitation for Concrete within Auxiliary Bldg G-line Wall. Initially Reported on 840329.Also Reported Per Part 21

ML20090K359
Person / Time
Site:	Grand Gulf
Issue date:	05/14/1984
From:	Mcgaughy J MISSISSIPPI POWER & LIGHT CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
REF-PT21-84 2, AECM-84-2-0005, AECM-84-2-5, NUDOCS 8405240176
Download: ML20090K359 (4)

Text

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l MISSISSIPPI POWER & LIGHT COMPANY

] Helping Build Mississippi M P. O . B O X 16 4 0, J A C K S O \1 MISSISSIPPI 39205 84 MAY 18 ^ 8 ; E 8 JAMES P. McGAUGHY JR. OF 8 WICE PRE SIDENT U. S. Nuclear Regulatory Commission Region II 101 Marietta Street, N.W.

Suite 2900 Atlanta, Georgia 30303 Attention: Mr. J. P. O'Reilly, Regional Administrator

SUBJECT:

Grand Gulf Nuclear Station Unit 2 Docket No. 50-417 License No. NPF-13 File 0260/15525/15526/16694.4 PRD-84/05, Interim Report No.

2 for Jnit 2, Main Feed Water Line Moment Guide Temperature AECM-84/2-0005 Re ference : AECM-84/0209, 4/2/84 On March 29, 1984, Mississippi Power & Light Company notified Mr. R.

Carroll, of your office, of a Reportable Deficiency at the Grand Gulf Nuclear Station (GGNS). The deficiency concerns the(galculated maximum temperature for the main feedwater line moment guides exceeding the original design basis limitation for the concrete within the auxiliary building G-line wall.

MP&L has determined that this deficiency is reportable under the provisions of 10CFR21 for Unit 1 and 10CFR50.55(e) for Unit 2. The Final Unit 1 10CFR21 Report was previously submitted per the referenced letter. All current details for Unit 2 are contained in our attached Interim Report. We expect to submit a Final Report for Unit 2 prior to Fuel Load.

Yours truly, p J. P. McGaughy, Jr.

KDS:dr ATTACHMENT cc: See page 2 8405240176 840514 COM PDR ADOCK 05000417 IN(q' tsb S PDR

& 5 t\

Member Middle South Utilities System

4 Mr. J. P. O'Reilly AECM-84/2-0005 NRC Page 2 cc: Mr. J. B. Richard Mr. R. B. McGehee Mr. Nicholas S. Reynolda, Esq.

Bishop Liberman, Cook, Purcell & Reynolds 1200 Seventeenth Street, N. W.

Suite'700 Washington, D. C. 20036 Mr. Richard C. DeYoung, DirecEor Of fice of Inspection & Enforcement U. S. Nuclear Regulatory Commission Washington, D.C. 20555 Mr. G.-B. Taylor South Miss. Electric Power Association P. O. Box 1589 Hattiesburg, MS 39401 i

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I Attachment to AECM-34/2-0005 Page 1 of 2 INTERIM REPORT NO. 2 FOR PRD-84/05, UNIT 2 I. Description of the Deficiency During low power operation of Grand Gulf Unit 1, the main steam line moment guides, located within the auxiliary building G-line wall, experienced an overheating problem. In reviewing the applicable calculations, it was discovered that heat losses from the uninsulated

. portions of the moment guides to the concrete wall had been neglected in the original analysis for the main steam and main feedwater lines.

-The temperature of' the concrete wall near .the main feedwater line moment guides could have exceeded 300*F, the design limiting tempera-ture of the G-line wall. Therefore, the potential exists for degrada-tion of concrete properties and strength. Howeve r , for the main steam

.line moment guides, the reanalysis indicated that the concrete tempera-ture. limits would not be exceeded. The deficiency is applicable to both Units 1 and 2; however, the deficiency has previously been reported under 10CFR21 for Unit 1. This report applies only to Unit

2. . Part 21 is not applicable for Unit 2 since the system has not been turned over to MP&L.

Degradation of the auxiliary building G-line wall, enclosing the main steam and main feedwater line moment guides, from temperatures in excess of the 300*F lbniting temperature could result in failure of the wall to perform its intended safety function as follows:

1. The wall forms a part of the secondary containment which in conjunction with the standby gas treatment system serves to limit doses within the guidelines of 10 CFR 100 and 10 CFR 50, during the design basis accident.

2. The wall contains the main steam and feedwater line moment guides which are necessary to pr.otect the outboard Main Steam Isolation Valves (MSIV's) from excessive loads due to a postulated pipe failure in the turbine building. The basis for these restraints is the NRC's Branch Technical Position MEB 3-1, Paragraph 3.1.b(1)(c).

Therefore, had the cited condition remained uncorrected, the deficiency could have af fected adversely the safety of operations of the nuclear power plant at'any time throughout the expected lifetime of the plant.

II. Approach to Resolution of Problem The cause of the deficiency was that the heat losses from the uninsulated portions of the moment guide to the concrete wall had been neglected in the original analysis for the main steam and main feedwater lines.

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, Attachment to AECM-84/2-0005 Prge 2 of 2 For Unit ' 2 a design review will be initiated based on the Design Change Package (DCP) issued to correct the problem for Unit 1.

The changes described in the DCP will be assessed by our Architect /

Engineer and additional alternatives will be reviewed during the engineering study of the problem for Unit 2.

III. Status of Proposed Resolution At this time the analysis of the safety implications has been completed and cause and extent of the deficiency have been determined. However, remedial actions and actions to prevent recurrence have not been formulated at this time. All. actions will be complete prior to Unit 2 fuel load. Our Architect / Engineer has issued MCAR 152 to track this concern for Unit 2.

IV. Resson Why Final Report is Delayed The' project schedule does not require the design of the moment guides to be completed in the near future; therefore, the design review and problem resolution will be performed at a later date commensurate with the' schedule requirements.

V. Date when Final Report will be Submitted A final report will be submitted prior to Unit 2 fuel load.