ML20249B597

Informs That DAEC Installed passive,large-capacity Suction Strainers on Core Spray & Residual Heat Removal Suction Lines During Refueling Outage 15 Re Actions Taken on NRC Bulletin 96-003

ML20249B597
Person / Time
Site:	Duane Arnold
Issue date:	06/15/1998
From:	Peveler K IES UTILITIES INC., (FORMERLY IOWA ELECTRIC LIGHT
To:	NRC (Affiliation Not Assigned), NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
IEB-96-003, IEB-96-3, NG-9801052, NUDOCS 9806230356
Download: ML20249B597 (2)

Text

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.a-FM A L Li A N T EM UTILITJES Amnt uise.

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200 nrst Street SE P.O. Box 351 Cedar Rapids,IA 52406-0351 O&e: 319.398.4411

. June 15,1998 ii,.ot.,,,,,y.,,,

NG-98-1052 Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Attn: Document Control Desk Mail Station PI-37

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Washington, DC 20555-0001

Subject:

Duane Arnold Energy Center Docket No: 50-331 Op. License No; DPR-49 NRC Bulletin 96-03," Potential Plugging of Emergency Core Cooling Suction Strainers by Debris in Boiling-Water Reactors,"

dated May 6,1996 o

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References:

1. NG-96-2279 dated November 1,1996, J. Franz (IES) to NRC.

'2. NG-97-1909 dated November 20,1997, J. Franz (lES) to NRC l

File:

' A-101a, E-11 l

On May 6,1996, the subject bulletin was issued to address a concern that debris could be L

transported to the suppression pool following a loss of coolant accident (LOCA) and deposited on the emergency core cooling system (ECCS) suction strainers. This could potentially result in a decrease in the net positive suction head (NPSH) available to the i

ECCS pumps.

By letter dated November 1,1996 (Reference 1), IES Utilities submitted an initial response to the bulletin stating that the Duane Arnold Energy Center (DAEC) would l

implement appropriate procedures and plant modifications by the end of refueling outage (RFO) 15. The purpose of this letter is to inform the NRC that the DAEC installed passive, large-capacity suction strainers on the core spray and residual heat removal suction lines during RFO 15, which was completed on May 22,1998. No additional procedures were required.-

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As discussed in Reference 2, the DAEC installed stacked disc strainers provided by Gen ~eral Electric (GE). The analytical methodologies for strainer sizing discussed in GE i

- Licensing Topical Report (LTR) NEDC-32721P were used. Also utilized were the analytical methodologies developed by the Boiling Water Reactor Owners' Group

(BWROG) contained in NEDO-32686, Utility Resolution Guidance (URG) for.

1 Emergency Core Cooling System (ECCS) Suction Strainer Blockage, as well as supplier l

test data to determine the strainer size necessary to maintain the required NPSH.when g!

considering insulation' debris, suppression pool sludge and other corrosion products, and 1

s 9 n V operational debris. Both the URG and the GE LTR are currently being reviewed by the l-

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,t June 15,1998 NG-98-1052 Page 2 Bulletin 96-03 required the submittal of a report confirming completion of all requested actions within 30 days. While the physical modification to the DAEC has been performed, several actions, including finalization of the NPSH calculations and revision of the licensing basis, can not be completed until issues pertaining to the LTR and URG are resolved between the NRC Staff, GE and BWROG. Final resolution of Bulletin 96-03 is also complicated by Generic Letter (GL) 97-04," Assurance of Sufficient Net Positive Suction llead for Emergency Core Cooling and Containment IIcat Removal Pumps" and proposed GL, " Potential for Degradation of the Emergency Core Cooling System and the Containment Spray System After a Loss-of-Coolant Accident Because of Construction and Protective Ceating Deficiencies and Foreign Material in the Containment."

Since all actions requested by the bulletin are not complete, this letter does not fulfill the bulletin's requirement to submit a report within 30 days. This report will be submitted within 30 days of completion of all actions, as required by the bulletin.

This !etter contains the following commitment.

The DAEC will complete its final close-out of Bulletin 96-03 following issuance of the NRC safety evaluation reports on the GE LTR and the BWROG URG.

Should you have any questions regarding this matter, please contact this office.

Sincerely, M4 f

Kenneth E. Peveler Manager, Regulatory Performance cc:

C. Rushworth E. Protsch J. Franz D. Wilson R. Laufer (NRC-NRR)

C. Paperiello (Region III)

NRC Resident Office DOCU

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