AECM-82-281, Interim Deficiency Rept Re Potential for Plant Flooding Based on PMP Flood Level,Initially Reported 820510.Complete Analysis Will Be Performed by 820630.Design Selection to Be Completed by 820630.Final Rept Provided by 820910

Interim Deficiency Rept Re Potential for Plant Flooding Based on PMP Flood Level,Initially Reported 820510.Complete Analysis Will Be Performed by 820630.Design Selection to Be Completed by 820630.Final Rept Provided by 820910

ML20054H711
Person / Time
Site:	Grand Gulf
Issue date:	06/16/1982
From:	Mcgaughy J MISSISSIPPI POWER & LIGHT CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
10CFR-050.55E, 10CFR-50.55E, AECM-82-281, NUDOCS 8206240352
Download: ML20054H711 (4)

Text

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MISSISSIPPI POWER & LIGH hPANY Helpin.c Build Mississig i , _

P. O. B O X 16 4 0, J A C K S O N , M i d 15@p P I 3 9 2 0 5 Aq JAMES P. McGAUGHY, JR.

June 16, 1982 *+gg ASSISTANT vlCE PRESIDENT Of fice of Inspection & Enforcement U. S. Nuclear Regulatory Commission Region II 101 Marietta Street, N.W.

Suite 3100 Atlanta, Georgia 30303 Attention: Mr. J. P. O'Reilly, Regional Administrator Dea r Mr. O'Reilly:

SUBJECT:

Grand Gulf Nuclear Station Units 1 and 2 Docket Nos. 50-416/417 File 0260/15525/15526 PRD-82/27, Interim Report, Plant Flooding AECM-82/281 On May 10, 1982, Mississippi Power & Light Company notified Mr. F.

Cantrell, of your of fice, of a Potentially Reportable Deficiency (PRD) at the Grand Gulf Nuclear Station (GGNS) construction site. The deficiency concerns the potential for plant flooding based on the Probable Maximum Precipitation (PMP) flood level.

Based on the results of our investigation, the determination has been made that this deficiency is reportable under the provisions of 10CFR50.55(e).

This deficiency has been determined to not have an impact on fuel load in that MP&L Plant Staf f committed to control possible internal flooding by using sandbags and procedural controls which will be available by fuel load.

Our Interim Report is attached. MP&L expects to submit a Final Report concerning this matter by September 10, 1982.

Yours truly ,

J. P. McGaughy, Jr.

ACP:dr ATTACHMENT cc: See page 2 8206240352 820616 PDR ADOCK 05000416 .

S PDR <M.7 g g Member Middle South Utilities System b bf

J Mr. J. P. O'Reilly AECM-82/281 NRC Page 2 cc: Mr. N. L. Stampley ,

Mr. R. B. McGehee Mr. T. B. Conner Mr. Richard C. DeYoung, Director Office of Inspection & Enforcement-U. S. Nuclear Regulatory Commission Washington, D.C. 20555 i

Mr. G. B. Taylor South Miss. Electric Power Association P. O. Box 1589 Hattiesburg, MS 39401 1

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Attachment to AECM-82/281 Paga 1 of 2 INTERLM REPORT FOR PRD-82/27 I. Description of the Deficiency A review of Grand Gulf Units 1 and 2 site has revealed a number of existing obstructions that were not considered or evident at the time the. original site drainage scheme was developed.- The cumulative effect of these obstructions raises the calculated Probable Maximum Precipita-tion (PMP) flood level to an' elevation that exposes the plant to some level of internal flooding.

This deficiency is applicable to the Bechtel Scope of Supply for both Unit 1 and Unit 2.

Multiple safety-related systems with components below grade elevation could be affected.

The unrestricted flow of water into Category I structures could adversely af fect the operation and safe shutdown of the plant by rendering safety related components and systems inoperable. Therefore, this deficiency is reportable under the provisions of 10CFR50.55(e).

11. Approach to Resolution of the Problem The cause of the deficiency was placement of structures and modifica-tions to permanent structures in manners which were not included in the original site drainage analysis. These changes would restrict the flow of water during severe rainfall events resulting in water levels higher than 133' outside safety-related buildings. The modifications / changes which created the condition are:

1. Seashell berms beside the security fence.

2. Parking lot elevations as high as 132.9'.

3. The road west of the Diesel General Building was constructed to elevations as high as 133.0'.

4. Presence of a headwall at a drainage ditch outlet.

5. Presence of trailers with plywood skirts which will block storm flow under the trailers.

The extent of the deficiency is limited to site drainage for Units 1 and 2.

Appropriate measures are being 'taken to provide for a barricade around Unit 1 Buildings to preclude internal flooding. based on a PMP event.

The specific design has not been finalized since there are several options to consider.

Barricades will be constructed around Plant buildings to prevent water entry during severe rainfall events.

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' Attcchaznt to AECM-82/281

.Pags 2 of 2 Plant flooding during Probable Maximum Precipitation (PMP) is included

aa License Condition 5 in the GCNS operating license. The wording is as follows:

"A. MP&L shall provide sufficient sand bags at entrances to safety-related structures. During periods of significant precipita-tion, these entrances shall be monitored.

When the water level reaches an elevation of one inch below the entrance, sand bags shall be applied to protect the entrances to one foot above the entrance.

B. Prior to exceeding 5% power, MP&L shall submit an analysis of PMP flooding and their plans for a ' permanent solution."

III. Status of Proposed Resolution The deficiency has been determined to be applicable to the the Bechtel scope of supply and the cause of the deficiency has been identified.

The extent is those components and systems which are located below elevation 133.0' in the plant. Our Architect / Engineer expects to complete an analysis of the PMP flooding by June 30, 1982. A design selection is expected to be complete by August 27, 1982.

IV. Reason Why a Final Report Will be Delayed The Final Report will be developed af ter a design has been finalized and a schedule determined for installation of flood barriers.

V. Date When a Final Report Will be Submitted-MP&L expects to submit a Final Report on this matter on or before September 10, 1982.

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