ML061910290
| ML061910290 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  (DPR-063, NPF-069) |
| Issue date: | 03/27/2006 |
| From: | Constellation Energy Group |
| To: | NRC/NRR/ADRO/DLR/RLRB |
| Le, Ngoc, NRR/DLR/RLRA, 415-1458 | |
| References | |
| Download: ML061910290 (16) | |
Text
Nine Mile Point License Renewal NMP1 Drywell Presentation to NRC LR Staff March 27, 2006
Nine Mile Point License Renewal NMP1 Drywell Presentation to NRC LR Staff March 27, 2006
3 Agenda
- Introductions Louis Larragoite
- Purpose Peter Mazzaferro
- NMP1 Drywell Design Peter Mazzaferro
- NMP1 Drywell Internal Condition Peter Mazzaferro
- NMP1 Drywell External Condition Robert Randall
- Conclusions Robert Randall
4
Introductions
- Louis Larragoite, Acting Manager, Fleet Licensing
- David Dellario, Director, Fleet Licensing Projects
- Robert Randall, Director, Ginna Licensing
- Peter Mazzaferro, NMP LR Project Manager
- Mohammed Alvi, Principal Engineer, Structural Design
5 Purpose
- Condition of interior surface
- Condition of exterior surface
6 NMP1 Drywell Design
- GE Mark I Containment
- Carbon Steel Shell surrounded by Reinforced Concrete
- ASTM-212 Grade B Firebox Steel
- Cylindrical Region Coated
- Shell Thickness in Cylindrical Region - 0.70
- Spherical Region Not Coated
- Shell Thickness in Spherical Region - 0.77 to 1.50
7 NMP1 Drywell Design
8 NMP1 Drywell Internal Condition
- ASME Section XI, Subsection IWE Examinations of Internal Surface (VT-3)
- 2001 Results - All Conditions Acceptable
- Surface Rust in Cylindrical Region
- Surface Rust in General Area of Spherical Region
- Slightly More Rust in 6 Localized Areas
- 2003 Results - All Conditions Acceptable
- Surface Rust in Cylindrical Region
- Surface Rust in General Area of Spherical Region
- Increased Rust in Same 6 Localized Areas Condition entered into corrective action program
9 NMP1 Drywell Internal Condition
- 2003 Supplemental Exams and Engineering Evaluations
- Detailed Visual Examination (VT-1)
- Surface Corrosion with No Pitting
- Acceptable per Code
- UT Thickness Measurements
- 4 UT Exams at Most Severe Conditions
- Measured Thickness from 1.106 to 1.131
- Design Acceptance Criteria 1.049
- Acceptable with respect to Design
10 NMP1 Drywell Internal Condition 2007 Re-Examinations per Code
- Visual Exam (VT-3) of Drywell Internal Surface
- Detailed Exam (VT-1) of Same 6 Localized Areas
- UT Measurements of Same 4 Locations 2007 Engineering Evaluation
- Project shell thickness at end of PEO based upon measured loss
- Determine if any additional inspections or actions are required Future Inspections in accordance with ASME Section XI, Subsection IWE and Engineering Evaluation Effective Aging Management Program Being Implemented to Prevent Loss of Intended Function of NMP1 Drywell
11 NMP1 Drywell External Condition
- GL 87-05 Identified Potential Degradation of Mark I Drywells
- Water Leaked Past Refueling Seal into Air Gap and Sand Cushion Area
- Corrosion Occurred on External Surface
- UT Measurements Confirmed Loss of Material
- NMP Confirmed Similar Condition Did Not Exist
- NMP Confirms Similar Condition Does Not Exist
12 NMP1 Drywell External Condition
13 NMP1 Drywell External Condition
- Sand Cushion Drain Lines (10)
- Portion of Drywell External Surface and Air Gap Adjacent to 2 Sand Cushion Drain Lines
- Reactor Head Cavity Seal Leakage Drain Area
- Results
- Sand Cushion Drain Lines Unobstructed
- Air Gap Dry and No Evidence of Water Intrusion
- Reactor Cavity Drain Lines Function Properly
14 NMP1 Drywell External Condition
- Refueling Seal Drain Welded vs. Gasket
- Drain Lines Unobstructed
- Leakage from Reactor Cavity Repaired
- Confirming Activities
- Periodic Visual Inspection of Sand Cushion Drain Lines (located in Torus Room)
- No leakage from Reactor Cavity Shelf Drains
15 Conclusions
- NMP1 Drywell Internal Condition Effectively Managed
- Implement ASME Section XI IWE Requirements
- Confirmatory UT Thickness Measurements
- Implement Additional Engineering Requirements
- NMP1 Drywell External Condition Effectively Managed
- Confirmed No Leak into Air Gap
- Leakage Collection and Drain Systems Functional
- Periodic Visual Inspections of Sand Cushion Drains
Nine Mile Point License Renewal NMP1 Drywell Presentation to NRC LR Staff March 27, 2006