ML20248L368
| ML20248L368 | |
| Person / Time | |
|---|---|
| Site: | Catawba  |
| Issue date: | 03/05/1998 |
| From: | Gordon Peterson DUKE POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| TAC-M99239, TAC-M99240, NUDOCS 9803200035 | |
| Download: ML20248L368 (5) | |
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Duke Power Company J
A Duke Ewy Gmpxy
~
Catawba Nudear Station b
4800 Concord Road I
York. SC 29745 Gary R. kereon (803) 831-4251 ornce We President (803) 831-3426 fax March 5, 1998 U.
S.
Nuclear Regulatory Commission ATTENTION:
Document Control Desk Washington, DC 20555-0001
SUBJECT:
Duke Energy Corporation Catawba Nuclear Station Units 1 and 2 Docket Nos. 50-413 and 414 Response to Recommendations and Observations in Dam Safety Inspection Report (TAC Nos, M99239 and M99240)
In a letter dated January 13, 1998, the results of the dam safety inspection related to the Category 1 Standby Nuclear Service Water Pond Dam were transmitted to Duke Power Company.. The inspection was conducted on February 27, 1997, and the final report contains five recommendations and observations related to the inspection.
Attached is Duke Energy Corporation's response to those recommendations and observations.
There are no commitments contained in the response.
Questions regarding this correspondence should be directed to M.H. Chernoff at (803) 831-3414.
Very truly
- ours, et, c
G. R.
Peterson Attachment I
DM D
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9803200035 980305 PDR ADOCK 05000413 G
PDR l
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U.S.
Nuclear Regulatory Commission
. Submittal Date Page 2 xc:
L. A. Reyes U. S. Nuclear Regulatory Commission Regional Administrator, Region II Atlanta Federal Center 61 Forsyth St.,
SW, Suite 23T85 Atlanta, GA 30303 P.
S. Tam NRC Senior Project Manager (CNS)
U.
S. Nuclear Regulatory Commission Mitil Stop O-14H25 W ashington, DC 20555-0001 D.
J.
Roberts Senior Resident Inspector (CNS)
U.
S. Nuclear Regulatory Commission Cataw'a Nuclear Site u
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U.S.1 Nuclear Regulatory Commission
.Atta*chment March 5, 1998 Page 1-Attachment The foll'owing-responses are provided.to the observations and recommendations given in the NRC Letter of January 13,1998,
Subject:
' Catawba Nuclear Station, Results of Dam. Safety
. Inspection'Related to the Category 1 Standby Nuclear Service Water Pond Dam (TAC Nos. M99239 and M99240).
The observations and recommendations are contained in Section E.
of'the. report and are tepeated in this attachment for completeness.
The responses are provided following the observations and recommendations.
1.
Increase the inspection frequency for the dam from quarterly to monthly.
Response
The current inspection frequency has proven to be satisfactory.
There has~been no evidence of l
degradation of the dam during its previous years of j
-service.
An increase in the inspection frequency does not appear warranted in view of previous inspection results.
~There is no requirement or commitment.in the Updated Final Safety Analysis Report to inspect the
-Standby: Nuclear Service Water Pond (SNSWP) Dam on-a monthly basis.
Operations personnel and Security-personnel are often in the area of the dam and pond.
Although these personnel have no-specific instructions, criteria, or requirements with respect'to inspecting the dam, these personnel are likely to notice and report any.
unusual conditions at the dam.
- 2. Rework the area surrounding piezometer P-7 to prevent 4
ponding rainwater and clean and test this instrument.
Response: ' Limited grading has been done around piezometer.P-7 so that the top of the, piezometer and the area around.the top of the piezometer are free of gravel
.and earth. The surface area has also been sloped so that it drains properly to prevent rainwater from ponding around the. top of the piezometer.
Preparations to clean and test the piezometer as recommended are in progress.
- 3. Conduct offset surveys of the surface monuments to monitor. horizontal movement.
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U.S. Nuclear Regulatory Commission
.Attdchment March-5, 1998 Page 2 Response:.There is no Updated Final Safety Analysis Report requirement to monitor for movement in the horizontal direction.
The dam monitoring program was established and has been maintained for settlement monitoring in the vertical direction.
The SNSWP Dam is an earth fill dam.
Any significant horizontal displacement (0.1 ft in accordance with Chapter II of the FERC ENGINEERING GUIDELINES FOR THE EVALUATION OF HYDROPOWER PROJECTS) would be accompanied by a measurable vertical displacement.
Vertical displacement is measured by reading of existing settlement monitors.
The full pond elevation of the SNSWP is elevation 574 ft.
The full ~ pond elevation of Lake Wylie (downstream side of the dam) is 569.4 ft.
Allowing for the fact that Lake Wylie could be several feet below full pond there would seldom be situations where there was more than about a 9 ft. head difference across the dam.
The dam is a massive structure that is-significantly overdesigned.
No
. horizontal displacement is expected.
In addition
-vertical settlement monitoring over the last fifteen years or so has shown negligible settlement in the vertical direction.
For.these reasons, horizontal monitoring ~of the surface monuments is not warranted.
- 4. Add a' surface monument on top of the outlet structure to monitor its vertical and horizontal movements.
Response
A monitoring point has been established and an initial elevation has been set up to provide for monitoring vertical movements of the outlet structure.
Any significant horizontal movements of the structure would be accompanied by vertical movement which will be measured.
The structure is inspected on an annual basis by qualified engineers during the engineering inspection of the dam.
Because of the vertical monitoring of the structure, horizontal monitoring of potential displacement of this structure is not warranted.
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- 5. Conduct periodic surveys of the reference benchmark in the plant from a USGS benchmark.
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U.S.
Nuclear Regulatory Commission Attschment March 5, 1998 Page 3
Response
The reference benchmark in the plant is located in the Unit 1 Reactor Building.
This benchmark in the Reactor Building is on QA Condition concrete that is founded on bedrock.
No settlement of this benchmark is expected, and therefore, reference of this benchmark to a USGS benchmark is not necessary.
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