ML20203A222

Forwards Request for Addl Info Re Recirculation Spray Sys (Significant Items List Items 1 & 85)

ML20203A222
Person / Time
Site:	Millstone
Issue date:	02/03/1998
From:	Imbro E NRC (Affiliation Not Assigned)
To:	Bowling M NORTHEAST NUCLEAR ENERGY CO.
References
NUDOCS 9802230307
Download: ML20203A222 (5)

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UNITED STATES '

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NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20665-0001 4

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February 3, 1998 Mr. Martin L. Bowling Recovery Officer Millstone Unit No. 2 Northeast Nuclear Energy Company c/o Ms. Patricia A. Loftus Director Regulatory Affairs P.O. Box 128 Waterford, CT 06385

SUBJECT:

MILLSTONE NUCLEAR POWER STATION, UNIT 3 - RECIRCULATION SPRAY SYSTEM (SIGNIFICANT ITEMS LIST ITEMS 1 AND 85)

Dear Mr. Bowling:

As prrt of the Millstone Unit 3 Restart Assessment Plan, the NRC staff is reviewing significant items list (SIL) Items 1 and 85, which address issues you reported and other design concerns regarding the recirculation spray system (RSS). Specifically, SIL ltem 1 addresses a condition where the RSS system pipe supports may experience stress levels in excess of the ASME Code allowables due to elevated temperatures resulting from post-loss of coolant accident containment design-basis accident conditions. SIL ltem 85 addresses several other problems with the design of the RSS system, including potentia; waterhammer, vortexing, and net positive suction head concerns. The NRC also has an inspection team reviewing the RSS system to i

verify the adequacy of the independent corrective action verification program (ICAVP) contractor. As part of this review and inspection, the NRC staff has reviewed a number of 10 CFR 50.59 evaluations you completed to support modifications to the RSS system. In addition, the staff has asked questions and received information conceming an operational change to the original NRC-approved design for the RSS system, which was made in the 1986 time frame.

Based on our limited review to date, it appears the design change in 1986, which was done under the provisions of 10 CFR 50.59, may not adequa'6y address the three questions of 10 CFR 50.59. Specifically, the eliminat.on of cold and hot leg direct injection during the cold and hot leg recirculation modes, respectively, did not consider the effects of long-term passive failures. In addition, it is the staff's understanding that an analysis of the impact of removing the direct injection path determined that the core melt frequency increased, thereby reducing the margin of safety. This information leads the staff to a preliminary conclusion that the modification may have involved an unreviewed safety question and, as such. may result in the need for license amendment request.

Since 1986, you have made numerous other design changes (including changes that require (f

additional operator actions) to the RSS system under the provisions of 10 CFR 50.59. All of these changes used, as a benchmark, the system design as modified in 1986. Therefore, in order for the NRC staff to continue its review of the recirculation spray system, Sllitems 1 and 85, and in particular, the basis for regulatory acceptance of the 1986 modification, we need you d

to address the enclosed request for additional information. If you determine that there is indeed an unreviewed safety question involved, your answers to the enclosed questions should be included in your safety evaluation as part of your license amendment.

9802230307 980203

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. The RSS system is required by the plant Technical Specifications to be operable prior to entry into Mode 4 operations, in addit on to the issues described above, during the staff's inspection of the RSS conducted as part of NRC's oversight of the ICAVP Tier 1 review, the inspection team has identified other issues which have been communicated to your staff as part of the ongoing inspection orocess. These findings will be documented in a forthcoming inspection -

report. Although these issues are preliminary in nature, they may call into question the operability of the RSS. Additionally, preliminary discrepancy reports issued by the ICAVP-contractor have identified possible nonconformances with Unit 3's licensing and design bases

. for systems that are required to be operational prior to entry into Mode 4. The preliminary findings of the NRC team and the ICAVP contractor should be considered as part of your operability determinations in preparation for entry into Mode 4. If you require additional information or clarification of any of the NRC team's findings please contact Gene Imbro at (301)-415-2379.

Sincerely, Original Signed by a Eugene V. Imbro Deputy Director for ICAVP Oversight Special Projects Office Office of Nuclear Reactor Regulation Docket No. 50-423

Enclosure:

Request for Additional Information cc w/ encl: See next page DISTRIBUTION:

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North::st Nucbir En:rgy Comp ny Millstona Nucle:r Pow;r Station Unit 3 cc:

Lillian M. Cuoco, Esquire S:nior Nuclear Counsel Northeast Utilities Service Company Mr. William D. Meinert P. O. Box 270 Nuclear Engineer Hartford, CT 06141-0270 Massachusetts Municipal Wholesale Electric Company Mr. Kevin T. A. McCarthy, Director P.O. Box 426 Monitoring and Radiation Division Ludlow, MA 01056 D:partment of Environmental Protection 79 Elm Street Joseph R. Egan,' Esquire Hartford, CT 06106 3127 Egan & Associates, P.C.

2300 N Street, NW R:gional Administrator, Region I Washington, DC 20037 U.S. Nuclear Regulatory Commission 475 Allendale Road Mr. F. C. Rothen King of Prussia, PA 19406 Vice President - Work Services Northeast Utilities Service Company First Selectmen P. O. Box 128 Town of Waterford Waterford, CT 06385 Hall of Records 200 Boston Post Road Emest C. Hadley, Esquire Waterford, CT 06385 1040 B Main Street P.O. Box 549 Mr. Wayne C,. Lanning West Wareham, MA 02576 D:puty Director of Inspections Special Projects Office Ernest C. Hadley, Esquire 475 Allendale Road 1040 B Main Street King of Prussia, PA 19406-1415 P.O. Box 549 West Wareham, MA 02576 Mr. M. H. Brothers Vice President - Operations Mr. John Buckingham Northeast Nuclear Energy Company Department of Public Utility Control P.O. Box 128 Electric Unit Waterford, CT 06385 10 Liberty Square New Britain, CT 06051 Mr. M. R. Scully, Executive Director Connecticut Municipal Electric Mr. James S. Robinson Energy Cooperative Manager, Nuclear Investments and 30 Stott Avenue Administration Norwich, CT 06360 New England Power Company 25 Research Drive Mr. David Amerine We.stborough, MA 01582 Vice President - Nuclear Engineering and Support Mr. D. M. Goebel Northeast Utilities Service Company Vice President-Nuclear Oversight P. O. Box 128 Northeast Utilities Service Company Waterford, CT 06385 P. O. Box 128 Waterford, CT 06385

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North:!st Nuciscr En:rgy Comp ny

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cc:

Deborah Katz, President Mr. Daniel L. Curry Citizens Awareness Network Project Director 4

P.O. Box 83 Parsons Power Group Inc.

Shelburne Falls, MA 03170 2675 Morgantown Road Reading, PA 19607 Senior Resident inspector Millstone Nuclear Power Station Mr. Don Schopfer i

clo U.S. Nuclear Regulatory Commission Verification Team Manager i

P.O. Box 513 Sargent & Lundy Niantic, CT 06357 55 E. Monroe Street Chicago,IL 60603 Mr. Allan Johanson, Assistant Director Office of Policy and Management Mr. J. A. Price Policy Development and Planning Unit Director-Millstone Unit 2 Division Northeast Nuclear Energy Company 450 Capitol Avenue - MS# 52ERN P.O. Box 128 P. O. Box 341441 Waterford, CT 06385 Hartford, CT 06134-1441 i

Mr. J. P. McElwain Citizens Regulatory Commission Vice President (Acting) - Millstone 3 4

ATTN: Ms. Susan Peny Luxton Northeast Nuclear Energy Company 180 Great Neck Road P.O. Box 128 Waterford, CT 06385 Waterford, CT 06385 4' '

The Honorable Terry Concannon Mr. G. D. Hicks Nuclear Energy Advisory Council Unit Director-Millstone Unit 3 Room 4035 Northeast Nuclear Energy Company Legislative Office Building P.O. Box 128 Capitol Avenue Waterford, CT 06385 i

.-Hartford, CT 06106

' Legislative Office Building Captiol Avenue Hartford, CT 06106 i

Mr. Evan.W. Woollacott Co-Chair i

Nuclear Energy Advisory Council 128 Terry's Plain Road Simsbury, CT 06070 4

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Little Harbor Consultants, Inc.

Millstone -ITPOP Project Office P.O. Box 0630 j

Niantic, CT 06357-0630 Mr. B. D. Kenyon Chief Nuclear Officer-Millstone Northeast Nuclear Energy Company P.O. Box 128

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Waterford, CT 06385

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REQUEST FOR ADDITIONAL INFORMATION MILLSTONE NUCLEAR POWER STATION. UNIT A DOCKET NO. 50-423

1. Based on the 1986 operational change to the recirculation spray system (RSS) and all the

- subsequent modifications made during the current outage, please provide an integrated safety assessment which compares the current system design to the original NRC-approved RSS design. This assessment should address significant changes to analytical models and inputs used to calculate thermal-hydraulic performance, containment pressure / temperature, and radiological dose consequences of postulated accidents.

2. Based on the limited staff review of the 1986 operational change to the RSS system, it appears that eliminating cold and hot leg direct injection resulted in a reduction to the margin of safety. Please address this concem.

3. Provide a description of each major RSS system modification and your determination of whether an unreviewed safety question exists.

4. Discuss the training received by operators on the modifications made to the RSS system since plant was shutdown, as well as any new insights revealed by the IPE for the current system configuration / operation.

5. Provide an evaluation of new operationalissues resulting from modifications to the RSS such as the vibration resulting from the installation of the flow restricting orifices.

6. With regard to the implementation of Technical Specification 6.8.4, describe the methods by which leakage from the RSS and associated systems outside containment will be controlled and monitored to ensure that the radiological dose consequences of postulated accident are within the plant's licensing bases.

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