ML17317B075
| ML17317B075 | |
| Person / Time | |
|---|---|
| Site: | Cook  |
| Issue date: | 04/06/1979 |
| From: | Dolan J INDIANA MICHIGAN POWER CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| AEP:NRC:00170, AEP:NRC:170, NUDOCS 7904120252 | |
| Download: ML17317B075 (7) | |
Text
REGULA TORY INFOHHATION DISTRIBUTION SYSTEM (RIDS)
ACCESSION NBR:7904120252 DOC ~ DATE: 79/04/06 NOTARIZED!
NO FACIL:5O" ONALO C ~
COOK NUCLEAR POWER PLANTq UNIT 1g INDIANA 0~
6 ONALD C ~
COOK NUCLEAR POAER PLANT g UiVIT 2 p INDIANA AUTH ~
'H Au I HOR aFFILIATION DOLANgJ,K ~
INDIANA 5 MICHIGAN POiiiER CO ~
REC IP < NAME RECIPIENT AFFILIATION OENTON H.H ~
OFFICE OF NUCLEAR REACTOR REGULATION DOCKET ¹ 05000315 05000316 SUB JECT:
REQUESTS SCHEDULE CHANGE IN TIvO UNIT THEHMAI PLUME MAPPINGS TO JUNE 1979
~ ALSO INFOR'4S NRC OF PROPOSED NOD TU DISCHARGE STRUCTURE SCOUR BED 10 ALLEVIATE FHOSION PHOl3LKMS ~ TWO OVEHSIZED STRUCtURAL DHAAINGS ENCL ~
OISTRIBUl'ION COOK:
COOOS COPIES RECEIVED:LTR J FNCL ~
SIZE:
TITLE: CHANGE REQUESTS FOR ENVIRON ~
TECH SPECS (APPEND 8)
~
NOTES:
~~
B
~~i-S fQ l ~TL RKC IPlfNT IO CODE/NAYiE ACTION:
05 BC og~~
INTERNAL:
0 ~-.F 10 BR liVKMAN 13 OELO 15 QAB 17 KNVN SPEC BH AO SI TF ANALYS 0IREC TOR OSK EXTERNAL: 03 LPDR 19 NATL LAB COPIES LTTR ENCL 5
RECIPIENT IO COOK/NAME 02 NRC PDR 11 ILK 14 KOO 8
STAFF 16 EEB 18 RAO ASMiT BR AD SYS/PHOJ 04 NSIC 22 ACHS COPIES LTTR ENCL 1
16 APR 13 197S TOTAL NUMBEH OF COPIES REQUIRED:
LTTH 00 ENCL
INDiANA R MICHIGAN POWER COMPANY P. O. BOX 18 BO WLI N G G R E EN STAT ION NEW YORK, N. Y. 10004 April 6, 1979 AEP: NRC: 00170 Donald C.
Cook Nuclear Plant Units 1 and 2
Docket Nos.
50-315 and 50-316 License Nos.
DPR-58 and DPR-74 Appendix B Technical Specifications Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U.
S. Nuclear Regulatory Commission Washington, D.
C.
20555
Dear Mr. Denton:
By this letter we would like (1) to request a schedule change in the'wo-unit thermal plume mappings for the Donald C.
Cook Nuclear Plant and (2) to inform the Commission of a proposed modification to the discharge structure scour bed.
Specification 4. 1. 1.2 of the Environmental Technical Specifications for the Donald C.
Cook Nuclear Plant specified four periods for two-unit thermal plume studies.
The last of such studies was to be completed by May 15, 1979, with the final monitoring period running from April 15 to May 15, 1979.
However, with Unit 1 coming down for refueling on April 6, 1979 and not returning to 75 percent power until after June 1,
1979, the original schedule cannot be adhered to for the last study.
In order to complete the plume mapping studies during 1979, we would like to extend the April 15 - May 15 monitoring period on into June, 1979.
As proposed, the final plume mappings would be performed as soon as practical after Unit 1 startup following refueling.
We request your approval of the proposed revised schedule.
We wish to inform you now about a modification to the Unit 1
discharge structure scour bed.
This modification will be initiated and completed during the forthcoming refueling outage of the Unit.
The same modification will be initiated to the Unit 2 discharge structure at a
later date, if required.
The discharge structure is located 1198 t't. from the screen
- house, approximately 900 feet offshore at a depth of about 18 feet.
The existing scour bed is made up of riprap ranging in size from 5 to 500 pounds.
The region directly in front of the nozzles and within the limits of the ice-guards is grouted.
These iceguards extend about the total periphery of the discharge structure.
Q 00
'7904 l202%2
'o 0
Nr. Harold R. Denton AEP: NRC: 00170 The problem encountered is twofold and stems from the need to have a high velocity for mixing the outflow with the ambient water.
The approximate average exit velocity is 13 feet per second at the.nozzles.
The first aspect of the problem is that as the water exits.
the structure it entrains the surrounding water and sets it into motion.
This motion con cause movement among the neighboring stones.
- Secondly, as the water exits the structure, it is affected by the presence of wave action.
As a zone of local high pressure passes over the nozzles, it deflects the jet downwards to form a trench in the scour bed.
The riprap then piles up and deflects the jet upwards to the surface of the lake where disturbance of the surface water is visible.
The plan and section of the present conditions are shown on Drawing No. 12-3721-6, attached.
As a temporary measure, the existing riprap was regraded and levelled to its original design elevation.
Nevertheless, the erosion problems continued.
A permanent solution was sought and a concrete scour bed was chosen.
The plan and section of the proposed scour bed are shown on Drawing No. 12-3722, also attached.
The following procedure will be used to place the concrete scour bed.
First, the existing riprap will be graded to approximate elevation of 558 feet.
This will halt the undermining problem.
The second step is to create a mattress with 1~"-5" stones placed to an elevation of 559'-2".
This mattress stone is much easier to level than the original riprap due to the smaller dimensions of the stones used.
This solid scour bed would prevent entrainment of water under the structure.
The next step would be to pour 2 feet of concrete over the mattress stone.
Concrete will also be placed within the confines of the iceguards which extend 6 feet out from the structure.
This area includes the sections in front of the nozzles as well as the sections on the sides for a total length of 129'-
2-5/8".
Any unused riprap will be used to alleviate any discontinuities of elevation between the concrete scour bed and the original riprapped scour bed elevation.
We expect that these repairs will alleviate the erosion problems that are presently occurring in the scour bed and directly affecting the operation of the discharge structure.
As per the guidelines furnished in 10 CFR 170, we classify this sub-mittal as a Class III Amendment.
Check No.ilseiin the amount of $4,400 is enclosed to cover the processing fee.
JED:
em Swor n and subscribed to before me this 4
day of April, 1979 in New York County, New York C 3"rz~~~
Notary Pub ic Yery trul
- yours, Z.
n
. Dolan
'ce President H c$
~o I/Q/
/
Mr. Harold R.
Oenton AEP: NRC: 00170 cc:
R.
C. Callen G. Charnoff P.
W. Steketee R. J. Vollen R. Walsh D. V. Shaller - Bridgman R.
W. Jurgensen
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