ML20106D316
| ML20106D316 | |
| Person / Time | |
|---|---|
| Site: | Hatch  |
| Issue date: | 09/27/1984 |
| From: | Beckham J GEORGIA POWER CO. |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| IEB-84-03, IEB-84-3, NED-84-300, NUDOCS 8410250088 | |
| Download: ML20106D316 (4) | |
Text
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' [333 Piedrnont Avenue Georgia Power Company
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- Atlanta. Georgia 30308 Telephone 404 526-7020
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Mailing Address:.
s Post Office Box 4545
' Atlanta, Georgia 30302 84 0CI 5 P3: 06 Georgia Power the southern elecinc sys:em
. J. T. aeckham, Jr..
g53 84-500 Vice President and General Manager '
Nuclear Generatton Septaber 27, 1984
.U. S. - Nuclear Regulatory Ccumission REIGRENCE:
Office'ofl Inspection and Enforceent RII: JIO
~ Region II:. Suite 2900 50-321/50-366 101 Marietta Street,!@i I&E Bulletin l Atlanta, Georgia-30303-84-03
- ATITNPION: Mr. Je es P. O'Reilly.
GENIUMEN:
Pursuant to a letter fra the Office of Inspection and Enforcment dated
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August =~ 24,.~1984, Georgia Power. C a pany hereby provides the following f response to IEE Bulletin 84-03, Refueling Cavity Water Seal.
Plant Hatch c
Unit 2 was in. the process of start-up at -the time of receipt of the Bulletin.
After consultation with the Plant Hatch NRC ' licensing project
+
. manager, it was determined that a response to the bulletin should be made
. before ~ begining the refueling. outage is scheduled to begin on or about 5"
September 29,~ 1984.
Gross seal failure:
. Hadde Neck, the subject plant of the bulletin, used pnanatic seals for the' refueling cavity seal. Plant Hatch uses two stainless steel bellows for ; each unit designed by Pathway.
One of the seals is installed between :the drywell and. the reactor well, and the other is between 'the drywell and the reactor vessel.
%ese bellows assablies are permanently -installed caponents with welded interfaces and do not require reinstallation each refueling operation.
Misaligreent of the type at Hadde Neck, therefore, is not possible.
he bellows itself is protected from daage by guard rings, and a leak
. detection syste is : installed to alarm on leakage. As a secondary seal,
'the bellows assably aploys a self-energized spring seal.
nis spring seal'is designed to limit water leakage by yielding to make a. tight fit to'the backing plate when subjected to the hydrostatic pressure in the
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- unlikely event of a bellows rupture.
%e only pnematic seals used at Plant-Hatch in refueling operations are on the-fuel pool gates and the expansion joint between Units 1 & 2 in the ' refueling canal.
%ese seals are a part of the gates and their aligment is assured by the gates' seating tolerance.
In the unlikely event of a seal lor gate failure, leakage would be prevented by the au 8410250088 840927 PDR ADOCK 05000321 G
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- U. S.-Nuclear Regulatory Ctsenission 1
Office of Inspection'and Enforcenent.
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- Atlanta, Georgia -30303
. September 27, 1984 Page ho redundant: gates'. at both. ends of the pool.
Wo gates.are installed at
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. the reactor vamaal transfer canal and two. gates 'at the Unit 1 shipping caskipool transfer canal.
'me expansion joint has redundant pnematic seals =on both Unit 1 Land Unit 2 sides.
In addition, there is another Enematic seal in the expansion joint itself.
~
Maximum leakage rate due to failure'of active c aponents:
Due to ' the radundant: pool-gates _ ' and expansion joint seals it is not postulated that.any significant~ leakage ; could - occur.
'Ihe refueling bellows maa=bly does not have any active caponents.
%erefore, no calculations to determine maxistan leakage rate have been perforned.
Makets) capacity: -
Makeup' water can be. provided by the condensate storage and transfer
~
' systen,- the domineralized water systen, the Residual Heat Renoval Systen, the. Residual Heat Renoval Service Water Systen, or the. Plant Service Water Systen. We primary makeup source,. the condensate storage and transfer systen, can-provide water from two 500,000 gallon. storage
- tanks that. are nonnally maintained at approximately 90% capacity or For' this operation both 500 gpn peps per unit can be run in more.-
-parallel.. %e Plant Service Water Systen provides a _ seisnic Category I source - of makeup' water to the spent fuel pools ~ and takes suction directly from the - Altanaha River.
Maximtsn filling ' capacity from the Plant ' Service Water Systen to the spent fuel pools is approximacely 350
. gym.
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Potential effect on stored fuel-and fuel in transfer:
~
For. the worst case scenario of a complete bellows assenbly failure with
- the spent fuel pool 3ates open, the lowest possible level to which the spent fuel pool can drain is 14 ft. 9 in. Below this level there are no
' outlets ' or drains from the pool.
%e active section of spent fuel stored in the pool ~ will renain covered with water.
M shown in the 2
Hatch Unit 2 FSAR evaluation in Section 9.1.2.3.1, boiling of the
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reaining ' water in the spent fuel pool will' not occur rapidly.
- Ourrective actions, -per procedures HNP-1/2-1949, HNP-1/2-2085, and HNP-1/2-2087, to be taken on low fuel pool level are:
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reposition the gates over the canal entrance;
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initiate makeup from condensate storage from the main control rom; y
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G orgiaPoiver L
U. S. Nuclear Pegulatory Coiunission Office of Inspection and Ehforement
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Atlanta,1 Georgia ^30303 Septaber 27, 1984'
'Pa;-e Three 3.s manually align-the. plant ~ service water systen in the reactor
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' building to provide pool makeup; and
' 4'.T 1 continue refilling the pool-to normal water level.
%e above scenario,' however,-is highly unlikely since it would require failure - of, both prest.ure boundaries of the bellows assenbly.
If the bellows., fails, leakage will most likely be detected upon initial filling
. of the Jrefuelir.g cavity and prior to the fuel' transfer operation.
^ Additionally, due to the welded and backup seal designs, it will not be Ja catastrophic failure but a leak.
his would permit the operator to secure fuel movment prior to uncovering fuel in transit. % erefore no
' analysis has 'been done to determine the effect on fuel in transfer. Any evaluation of uncovered fuel in - transfer is essentially a new DBA and any. consideration would require. extensive generic evaluation not empleted to date. It has been concluded that the effect on stored fuel
-has been evaluated in the Hatch Unit 2 FSAR and is of no consequence.
/ Time to cladding danage without operator action:
Cladding damage to fuel in the spent fuel pool will take in excess of
'3.51xxars after the pool has drained to its lowest possible level. %is is the time calculated for the minimun water level inventory to begin to boil and is reported in Hatch Uhit '2 ESAR Section 9.1.2.3.1.
%is time period plus the time fra initial boiling to cladding failure will allow for corrective actions to be taken.
DamageLto fuel-in the reactor vessel will not occur since it will never
' be uncovered, and since the shutdown cooling systen will not be degraded by a bellows rupture.
~
Bnergency operating procedures:
- The _ emergency operating procedures (HNP-1/2-1949, HNP-1/2-2085, and
. ItiP-1/2-2087) reflect the corrective actions discussed previously and listed in Uhit 2 FSAR Section 9.1.2.3.1.
named on the above, it is not considered credible to have a seal failure at
' Plant Hatch similar to that' which ~ occurred at Haddan Neck.
Further, the
~conseguences of such a postulated failure at either Unit will not result in
_ any ' adverse - effects on plant or public safety.
%erefore, no corrective
~
actions are required.
If you have any further questions, please contact this' office.
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,.b GeorgiaPower d U. S. Nuclear Regulatory Camission Office of Inspection and Enforc eent Atlanta, Georgia 30303 Septaber 27, 1984 Page Four J. T. Beckhm, Jr. states that he is Vice President of Georgia Power Capany and is authorized to execute this oath on behalf of Georgia Power Capany, and that+o the best of his knowledge and belief the facts set forth in this, letter are true.
GEORGIA IGER OCMPANY By:
J. T. Beckh m, Jr.
Sworn to subscribed bef re me this 27th day of Septenber,1984.
Notary Pubhc, Georgia, State at Large
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My commission boires Sept.18,1987
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Notary Public
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MJB xc:
H. C. Nix, Jr.
Senior Resident Inspector Docment (bntrol Desk, Wash.
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