ML20031D323

Amends Interim Deficiency Rept 1 Re Failure of Control Rod Driveline Hydraulic Sys Scram Pilot Valves,Initially Reported 810826.Reportability Under Part 21 Not Determined, Correcting Statement in

ML20031D323
Person / Time
Site:	Grand Gulf
Issue date:	10/01/1981
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-81-379, NUDOCS 8110130246
Download: ML20031D323 (3)

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MISSISSIPPI POWER & LIGHT COMPANY Helping Build Mississiopi mAMININE P...Q..B OX.164 0, J A C K SO N,. M I G SI S S L P P I.3 9 2 0 5 D[4rTN[cIi[

October 1, 1981 8 '

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Office of Inspection & Enforcement s

U. S. Nuclear Regulatory Commission Q gpF q

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101 Marietta Street, N.W.

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Suite 3100 i

OCT131981* -8 Atlanta, Georgia 30303 u.t nun emuos s.

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Attention:

Mr. J. P. O'Reilly, Director g

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SUBJECT:

Grand Gulf Nuclear Station Units 1 and 2 Docket Nos. 50-416/417 File 0260/15525/15526 PRD-81/35, Amended Interim Report #1, Failure of CRD Hydraulic System Scram Pilot Valves AECM-81/379 On August 26, 1981 Mississippi Power & Light Company notified Mr. Virgil Brownlee, of your office, of a Potentially Reportable Deficiency (PRD) at the

. Grand Gulf Nuclear Station (GGNS) construction site.. The deficiency concerns the failure of the Control Rod Drive (CRD) Hydraulic System Scram Pilot Valves.

We have determined that this deficiency, had it remained uncorrected, would have affected the safety of operations of the nuclear power plant and is report-able under the provisions of 10CFR50.55(e). We have not determined reportabil-ity under 10CES21.

Our Interim Report No. 1, sent to you September 25, 1981, incorrectly contained the statement "Since the deficiency is not a received component, or a failure to comply, this deficiency is not reportable under the provisions of 10CFR21" in paragraph II.

This statement should have read, "We are continuing our investigation into reportabil.ity under 10CFR21." We apologize for the error and regret any misunderstanding it might have caused.

Yaurs truly, J. P. McGaughy, Jr.

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See page 2 gfft 8110130246 811001 PDR ADOCK 05000416 S

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- Mr. J. P. O'Rei,lly.

AF.,& 81/.379 - -.

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Mr. N. L. Stampley Mr. R. B. McGehee Mr. T. B. Conner Mr. Victor Stello, Director Office 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

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Hattiesburg, MS 39401 4

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'ss' Atttchment to AECM-81/366 Page 1 of I

..... AMENDED. INTERIM REPORT #1 FOR PRD-Sl/35. _

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Description of the Deficiency During Control Rod Drive (CRD) testing, fourteen (14) scram pilot valves were found stuck in the energized state when both of the solenoids were de-energized. This prevents the actuation of the scram inlet and outlet valves and *.hus prevents the control rods from scraming. The deficiency affects only the Control Rod Drive (CRD) Hydraulic System (System C11) in Unit 1.

II.

Analysis of Safety Implications This situation could lead to the failure of the Control Rods to scram and jeopardize the reactor pressure boundary and nuclear fuel integrity.

This deficiency could affect the safety of operations of the nuclear power plant and is reportable under the provisions of 10CFR50'.55(e). We are continuing our investigation into reportability under 10CFR21.

III.

Corrective Actions Taken The valves that failed did not contain a defect. They were damaged by being operated with insufficient voltage being supplied to the solenoid coils by the. Reactor Protection System due to insufficient cable size.

The low voltage caused " chattering" of the solenoid core internals, resulting in damage and subsequent sticking of the internals, preventing proper operation.

The deficiency was caused by cables o'f ins lficient capacity being used to supply power to the solenoid valves, resulting in less than minimum voltage being supplied. The affected Reactor Protection System Supply l

Cables are being replaced with cables of sufficient capacity. All scram pilot valves are being rebuilt to replace all damaged parts.

Corrective actions will be completed by October 31, 1981.

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Since all defective valves will be repaired and all affected undersized cables will be replaced, this will serve to preclude recurrence of the problem.

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__ Reason Why a Final h port Will Be Delayed IV.

We are currently investigating applicability of 10CFR21. Our final report will be submitted December 1,1981.

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