ML20137C263
| ML20137C263 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 03/17/1997 |
| From: | Shell R TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9703240196 | |
| Download: ML20137C263 (4) | |
Text
!
e f
i i
j Tennessee Valley Authority, Post omce Box 2000, Soddy-Daisy, Tonnessee 37379-2000 March 17,1997 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555 Gentlemen:
in the Matter of
)
Docket No. 50-327 Tennessee Valley Authority
)
50-328 SEQUOYAH NUCLEAR PLANT (SON) - NRC REQUEST FOR ADDITIONAL INFORMATION - REVIEW OF TECHNICAL SPECIFICATION CHANGE 96-05 REGARDING VOLTAGE-BASED ALTERNATE REPAIR CRITERIA FOR STEAM GENERATOR TUBES SEQUOYAH UNITS 1 AND 2
Reference:
TVA letter to NRC dated March 12,1997,"Sequoyah Nuclear Plant (SON) - NRC Request for Additional Information-Review of Technical Specification Change 96 -
05 Regarding Voltage-Based Alternate Repair Criteria for Steam Generator Tubes Sequoyah Units 1 and 2."
In response to NRC questions from a teleconference on March 17,1997, TVA is providing a clarification to page 6 of enclosure 1 from the j
referenced letter. The clarification revises the language from "If a TSP j
elevation has less than 50 dented intersections" to "If a TSP elevation has less than 250 dented intersections." This change ensures that a 20 percent expansion of the buffer zone would equate to a sample size of 50 dented TSP intersections.
4 Enclosed is the revised page 6. This page supersedes the page 6 previously provided in the referenced letter.
t 9703240196 970317 C)C')I l
PDR ADOCK 05000327 P
PDR llEEpBippBR,RJIR
I
?
i U.S. Nuclear Regulatory Commission l
Page 2
]
March 17,1997 j
i L
-Please' direct questions concerning this issue to Don Goodin at (423) 843-l-
7734.
1 L
l Sincerely, R. H. Shell Site Licensing and Industry Affairs Manager l
i l
cc:
R. W. Hernan, Senior Project Manager l,
Nuclear Regulatory Commission L
One White Flint, North l
11555 Rockville Pike l-Rockville,- Maryland 20852-2739 NRC Resident inspector Sequoyah Nuclear Plant 2600 Igou Ferry Road Soddy-Daisy, Tennessee 37379-3624 i
\\
Regional Administrator i
U.S. Nuclear Regulatory Commission Region ll 101 Marietta Street, NW, Suite 2900 L
Atlanta, Georgia 30323-2711
\\
l' j
-l I
I i
l
1 o
Enclosure Sequoyah Nuclear Plant Revised Page 6 to TVA letter dated March 12,1997.
i
)
)
i
)
Attachmnnt 1 (continutd) 3 Unit 1 Dent Sampling Plan for dents less than 5 volts; 1
TVA will sample with RPC in a SG all dents less than 5 volts at all TSP elevations (and lower TSPs) where, based on past inspections, degradation has occurred (defining a critical area) and perform a 20% sample of the next higher TSP elevation (a buffer zone) to bound the affected area. The buffer l
zone, in this application, is the next higher tube support plate elevation where l-no degradation has been observed. This buffer zone area is to ensure that the critical area is bounded. The degradation (circumferential ODSCC or PWSCC i
not detected by bobbin coil) identified from the past dented TSP inspection would determine the initial sample.
I Each SG initial sample will be determined independently, if no degradation l
was identified in the past inspection, a minimum 20% sample of the dents (less than 5 volts) at the first TSP will be examined. During future outages a different 20% sample would be inspected, such that over five outages 100%
l of the dents at this elevation would be inspected.
if indications are identified in the buffer zone, this sample will be expanded in l
accordance with Table 2. Any indication identified that exceeds the plugging limit shall be repaired. The buffer zone result classification as defined in TS Section 4.4.5.2 shall be utilized, except when a sample size is less than 200, then only C-2 results apply.
l Alternative Dented TSP Inspection Program (greater than or equal to 5 volts);
TVA proposes an alternative inspection program for SGs 3 and 4, for the j
greater than 5 volt dents which is the same methodology as the proposed i
program for less than 5 volt dented tube support plate inspection with one additional requirement. If a TSP elevation has less than 250 dented l
intersections when selecting a buffer zone, then additional intersections at the next higher elevation shall be inspected to make the total number of l
Intersections to be inspected equal to 50. TVA would like the option to employ either method to the greater than or equal to 5 volt dent population.
l l
.