HL-1323, Submits Addl Info Re Implementation of ATWS Mods
| ML20058A751 | |
| Person / Time | |
|---|---|
| Site: | Hatch  |
| Issue date: | 10/19/1990 |
| From: | Hairston W GEORGIA POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| HL-1323, NUDOCS 9010290149 | |
| Download: ML20058A751 (2) | |
Text
co n or w cvnswy
... ~.
.Aiwa.>nva m j
Tuenw.n e4 ta, ms
,w,wn.
NO$7$NIl5 nonfa.na miu3rm let phone PD5 Nh Eh t i
t'n v a">o u t m n w.te",
W. G. Hairston, til Servor Vrct Presdent HL-1323 001205 October 19, ;990 U.S. Nuclear Regulatory Commission ATTN:
Document Control Desk i
Washington, D.C.
20555 PLANT HATCH - UN'.iS 1, 2 NRC DOCKETS 50-3f.1, 50-366 OPERATING LICENSES OPR 57, NPF-5 ADDITIONAL INFORMA fl0N REGARDING IMPLEMENTATION CF ANTICIPATED T_RANSIENTS WITHOUT SCRAM (ATWS) MODIFICATIONS Gentlemen:
The following information is provided to clarify two aspects of Georgia Power Company's (GPC) implementation of modifications required by the ATWS
- rule, 10 CFR 50.62.
The clarifications supplement information originally provided in our March 4, 1987 submittal on this topic and document information verbally provided during the NRC's inspection o f. Our implementation of the required ATWS modifications which concluded on September 14, 1990.
The clarifications pertain to the implementation of the Alternate Rod Insertion (ARI) system at Plant Hatch - Units 1 and 2.
The first item concerns the ARI performance criterion that control rod insertion motion will begin within 15 seconds and be completed within 25 seconds from ARI initiation time.
This generic ARI performance criterion was referenced in our March 4, 1987 submittal with the notation that pre-operational testinc of ARI would confirm whether this criterion was met.
Such ARI pre-operational testing demonstrated that approximately 80% of the Hatch Unit I control rods and approximately 99% of the Hatch Unit 2 control rods met the 25 second full-in insertion requirement. A plant unique, bounding assessment of the actual rod insertion times was performed by General Electric which demonstrated their acceptability, based on evaluation of the Scram Discharge volume (SOV) fill time and an assessment that all ARI design objectives, as. previously approved by the NRC, continued to be met.
It should be noted that the percentage of control rods which exceeded the generic 25 second full-in insertion requirement is not a key parameter in the plant unique assessment; the assessment provides a new, plant unique value for the full-in insertion requirement (35 seconds for Unit 1 and 41 seconds for Unit 2).
The maximum time for any rod to insert was 27.93 seconds for Unit I and 25.1 seconds for Unit 2.
90tbSE1I*001019 7
neoce moog gi i/o
0 Oc[Ngiitibwer b U.S. Nuclear Regulatory Commission October 19, 1990 Page Two The second clarification concerns the power supply for ARI which was incorrectly identified as the Class IE 125/250 VDC Station Battery system in our March 4, 1987 submittal.
The actual power supply for AR1, as originally designed and implemented on Units 1 and 2, is the Class lE Diesel Battery System. This power supply is independent from the Reactor Protection System (RPS) power supply as reouired.
If you have any further questions in thic regard, please contact this office at any time.
Sincerely, s.j W W. G. Hairston, 111 CLT/eb c: Georaia Power Company Mr. H. L. Sumner, General Manager - Nuclear Plant Mr. J. D. Heidt, Manager Engineering and Licensing - Hatch GO-NORMS U.S. Nuclear Reaulatory Commission. Washinaton. D.C.
Mr. F. Rinaldi, Acting Licensing Project Manager - Hatch U.S. Nuclear Reaulatory Commission. Reaion 11 Mr. S. D. Ebneter, Regional ACainistrator Mr. L. D. Wort, Senior Resident Inspector - Hatch i
001205