ML19296B501

Clarifies Items 5 & 6a of IE Bulletin 79-02,Revision 2,per Gallagher Request.Contrary to Util 791207 Ltr,Containment Insps Revealed No Seismic Category 1 Hangers.Approx 30% of Hangers Had Structural Steel Shapes Base Plates

ML19296B501
Person / Time
Site:	Prairie Island
Issue date:	02/04/1980
From:	Gilberts D NORTHERN STATES POWER CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
IEB-79-02, IEB-79-2, NUDOCS 8002200713
Download: ML19296B501 (2)

Text

a n

..; ilC MSP N O R T H IC R N STATES POWER COMPANY M I N N E A POI.I S. M I N N E S OTA 5 5 409 February 4, 1980 Mr. James G. Keppler

, Director - Region III Office of Inspection and Enforcement U. S. Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, Illinois 60137 M ar Mr. Keppler:

PRAIRIE ISLAND NUCLEAR GENERATING PLANT Docket Nos. 50-282 License Nos. DPR-42 50-306 DPR-60 To clarify items 5 and 6a of IE Bulletin 79-02, Revision 2, as requested by Mr. Gallagher of your office, and to update you on the status of the testing program, the following information is offered:

1. We incorrectly informed you in our letter dated December 7, 1979, that two Seismic Category 1 hangers were supported via concrete block walls.

Only one Seismic Category 1 hanger is supported via concrete block wall; it is 'ocated on a 2-inch CVCS line inside Unit 1 containment. This hanger has a safety factor of plus twenty, based on design loads for con-crete; therefore, it poses no safety hazard. At the earliest opportunity, the support will be relocated from the concrete block wall to a concrete structure. Inspections inside Unit 2 containment revealed no Seismic Category 1 hangers installed in concrete block walls.

2. Approximately 30 percent of the hangers installed at Prairie Island had base plates made from structural steel shapes. These shapes were in-cluded in our actions performed for this bulletin as indicated in our letter dated December 7, 1979. The attached table indicates the number of structural steel supports by system and by approximate location.

3. Field verification of the Seismic Category 1 restraints that use concrete expansion anchors has been completed inside Unit 2 containment. Direct pull tests (tensile tests) were performed on 130 concrete expansion anchor bolts inside Unit 2 containment with one anchor slipping. Modifications /

repairs are still in progress to upgrade the anchor loadings to PU/5.

Yours truly, 2h D. E. Gilberts MS Vice President . j,

' ~

Power Production Enclosure C

\

(.O cc: Mr. G. Charnoff NRC Office of Inspection and Enforcament Washington, D. C.

8002200 7/3

LOCATION & OUANTITY .s Inside Containment Outside Containment System Unit 1 Unit 2 Unit 1

• Unit 2 Cooling Water 3 --- 90 15 Caustic Addition --- --- 1 1 Containment Spray --- ---

10 8 Residual Heat Removal ---

2 7 5 Spent Fuel Pit --- ---

14 ---

Main Steam --- ---

1 ---

Hydrogen Control 1 2 5 5 Aux Feed Water ---

2 33 .6 CVCS 35 2 46 14 Fuel Oil --- ---

86 ---

Component Cooling --- ---

40 30 Safety Injection 20 1 21 7 S/G Blowdown 7 --- --- ---

Reactor Coolant 3 2 --- ---

,