ML20245B780

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Responds to IE Bulletin 84-03 Re Refueling Cavity Water Seal.Only Pneumatic Seals Used at Plant Are on Fuel Pool Gates.Leakage Would Be Prevented by Redunant Gates at Both Ends of Pool.Supporting Documentation Encl
ML20245B780
Person / Time
Site: Hatch  Southern Nuclear icon.png
Issue date: 09/19/1984
From: Beckham J
GEORGIA POWER CO.
To: James O'Reilly
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML20245B770 List:
References
FOIA-87-76 IEB-84-03, IEB-84-3, NUDOCS 8707010297
Download: ML20245B780 (9)
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NED-84-500 Septancer 19', 1984 U. S. Maoisar Regulatory Ozmission REFEREN3:

Office of Ingestion and Enforcement RII: JPO Region II - Anite 2900 50-321/50-366 101 Marietta street, W I&E R211etin Atlanta, Georgis 30303 84-03 ATIINTION: Mr. James P. O'Reilly -

GENTLDEN R2rsuant to a letter from the Office of Inspect' ion and Enforcement in Washington dated Aagust 24, 1984, amorgia power onpany, hereby provides the followire response to I&E R111stin 44-03, Refueling . Cavity Water seal.

Unit 2 was in the process of startep at the time of receipt of the Rauetin. After canaJ1tation with eur licensing project manager at NRR, it was decennined that our regense aheuld come before begining refueling on Unit 1. Se Unit 1 outage is ache & led to begin approximately September 28, 1984.

Gross seal failures Eaddam Neck, the subject plant, used pneumatic esals for the refueling.

cavity seal. P3 ant Hatch uses two stainless steel bellows for each unit designed by Pathway one of which is installed between the drywell and o the reactor well and the other Betwen the drywell and the reactor vessel. mese bellows asasablies are permanently installed cenponents

' with welded irgerfaces. Misalignment therefore is not possible because the bellows do nos reg 2 ire reinstallation each refueling operation.

De bellows itself is protected from damage by pard rings and a leak detection system is installed to alarm on leakage. As a secondary seal the bellows assembly uses a se33 energized spring seal. his sprin; seal is designed to limit utar leakage in the unlikely event of a beuows rupture by yielding to make a tight fit to the backing plate -

when subjected to the hydrostatic presa2re.

We only pneumatic esals used at Batch are on the fuel pool gates.

@ese seals are a part of the gates and their alignment is asaared by the gates' seatirg talarance. n the unlikely event that a seal or gate waald fail, leakage would be prowented b/ the re&ndant gates at both ends of the pool. 'No gates are installed at ' the reactor vesse1~

transfer canal and two gates at the shipping cask pool transfer canal.

Maximam leakage rate he to failure of active cerconents:

nas to the re&ndant pool gates it is not assumed that any significant

. laakage coald occur and the refuelling bellows assembly does not have art / active conponents. Derefore, re calculations to deter:r.ine mnxt:m laakage rate have been perfonned.

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. Office of 2ngection and Enforcement Atlanta, Georgia 30303 september 19, 1984 Page D e MakeJo capacitys Naheup water can be provided by the condensata storage and transfer system, the domineralised water system or the plant service water systaa. ghe primary ashaup source, the condensata storage and transfer system, can provide water feca tuo 500,000 gallon storege tanks that are rusmally maintained at appseximately 906 especity or more. For this operation both 500 gym pasps can be run in.pera11a). The plant service I water system provides a metamic category I acurce of makeup water and takes anotion directly from the Altamaha rieer. .Naminum filling capacity from the plant servios water syatam is approximately 350 gym.  !

Potential effect on stored Sael and d el in transfer For the worst case apenario of a couplete bellows assembly failure ard tre spent Siel pool gatas open, the lowest possible level to which the .l spent Asel pool can drain is 14 ft.9 in. Below this level there are no -i outlets or drains from the pool. 2e active section of spent fuel I stored in the pool will'rensin cotered with water.. Per the Hatch Unit 2 i

(- PSAR evaluation in Section 9.1.2.3.1 rapid boiling of the remaining water in the spent Stel pool will not occur. Corrective actions to be taken on low dael pool level are: *

, 1. reposition of the gates over the canal entran:e  ;

2. initiate makasp from condensate storage from the main control room

. 3. mamally align the plant service matar systerr. in the reactor bJilding to provide pool makesp 4 oontime refilling the pool to rer:r.a1 water louel Se ateve scenario however is highly unlikely since it muld reGJire failure of both pressure boundaries of the bellows assembly. If the bellows fails, leakage will sont likely be detected upon initial filling of the refJeling oavity and prior to the fuel transfer operation.

Additionally, Ate to the welded and backap anal designs, it will not be a catastrophic failure hat a leak. Wis will permit the operator to secure fuel movement prior to urcocering. fuel. Berefore no analysis has .been done to determine the effect on fuel in transfer. Any -

evaluation of urcovered fuel in transfer is practically a new DBA. and aq/ effort would reeaire extensise generic evaluation not ' completed todate. It has been concluded that any effect on stored fuel have been

. evaluated in the Hatch Unit 2 FBAR ard are of no consegaerce.

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U. 5. Itaclear Regalatory Cbmaiselon Office of Inspection and Enforcement -

I Atlanta, Georgia 30303 ,

l September 19, 1984 '

Page tree Time to claddire damage without operator actions cladding damage to ibel in the spent Anel pool will take in esemess of 3.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> after the pool has drgined to its lowest possible level. 21s is the time calmisted for the mininum water level inventory to begin to boil and is reported in Rats tmit 2 FBAR Section 9.1.2.3.1. 21s time period plus the time free initial boility to oladding failure will allow I for corrective actions to be taken. .

Damage to Anel in the reactor vessel will not ochtr since it is neier uncovered and since the atsatdown cooling system will not be degraded by a bellows supture.

1pergency operatire WMres: -

Se emergency operating HMres QDEP-1-2087,19tP-1-2085, }DEP-2-2087, and 1stP-2-2005) reflect the corrective actions discussed previously and listed in FRAR Section 9.1.2.3.1.-

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Based on the atre, it is not considered credible to he"e a seal failure at  !

Plant }iatch similar to the one that occurred at Baddam Neck. Also the I conaeasences of a ch a postulated fa(lure will not reaalt in any adverse effects on plant or public safety for- ei,gher Unit. Berefore, no correctits )

actions are reasired.

If ycu have any further gaestions, please contact this office.

J. T. Beckham, Jr. states that he is Vice President of Georgia Power Company and la mathorised to executs this oath on behalf of Georgia Power ocmpany, ard that to the best of his knowledge ard belief the facts set forth in this letter are true.

GEDIGIA poler CDMPAhY  ;

By:

J. T. Beckham, Jr.

Sworn to ard asbecribed before me this 19th day of September,1984.

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office of Inspection and Enforoomnt '

-( Atlanta, Georgia 30303 september 19, 1984 l

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xc H. C. Nix, Jr.

Senior Resident Inspector Document control Desk, tensh.

Tortsces I4c. Engr.1 Ei..Mgr.:Mgr. 6 CNE:

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learname: ! Blackwood! Baker  ! GJewa !k senberg ! Nix  !

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- Bechtel Power Corporation

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gg Engineers - Constructors 5/g 15740 Shady Grove Road RESP.A'.rJ.

/ Gaithersburg. Marytand 206771454 '

301 - 258 3000 Mr. L. T. Gucwa september 18, 1984 Nk Georgia Power Company SEP 241984 P.O. Box 4545 Atlanta, Georgia 30302 -

" CH "ANAGEMENT E. I. Hatch Nuclear Plant . Units 182 Bechtel Job 6511-057 - R612BR (

- IE SULLETIN 84-03 RESPONSE File: A29.3/A3.4 (84-03)/8-GP-12762-

Dear Mr. Gucwa:

f In response to letter NED-84-469 dated August 29, 1984 we offer the following information relative to 1.E. Bulletin No. 84-3. This I.E. Bulletin is concerned with gross leakage of the water inventory in the refueling cavity and the spent fuel pool during refueling operations as a, result of cavity seal failure.

, _ GROSS SEAL FAILURE

  • i Haddam Neck, the subject plant, used pneumatic seals for the refueling cavity seal.

Plant Hatch uses stainless steel bellows designed by Pathway, one is installed between the drywell and the reactor well and the other is installed between the drywell and reactor vessel.

These bellows assemblies are permanently installed components with welded interfaces. Misalignment therefore is not possible because the bellows do not require reinstallation each refueling operation.

The bellows itself is protected from damage by guard rings and a leak detection system is installed to alarm on leakage. As a secondary seal the bellows assembly uses a self energizing spring seal. This spring seal is designed to limit water leakage in the unlikely event of a bellows rupture by yielding to make a tight fit to the backing plate when subjected to the hydrostatic pressure.

The only pneumatic seals used at Hatch in refueling operations are on the fuel pool gates and at the expansion joint between Units I and 2. The gate seals are seating a part of the gates and their alignment is assured by the gates tolerance.

In the unlikely event that a seal or gate would fail, leakage would be prevented by the redundant gates at both ends of the pool.

Two gates are installed at the reactor vessel transfer canal and two gates at the shipping cask pool transfer canal. The expansion joint has permanently installed redundant pneumatic seals on both the Unit I and Unit 2 sides. In addition there is a pneumatic seal in the expansion j in .

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t Mr. L. T. Gucwa 2 B-GP-12762 September 18, 1984 MAXIMUM LEAXAGE RATE DUE TO FAILURE OF ACTIVE COMPONENTS Due to the redundant pool gates and expansion joint seals it is not assumed l that any significant leakage could occur. The refueling bellows assembly l does not have any active components. Therefore, no calculations to {

detennine maximum leakage rate have been performed.

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MAKEUP CAPACITY ,

Makeup water can be provided by the condensate storage and transfer system, the demineralized water system or the plant service water system. The primary makeup source, the condensate storage and transfer system, can provide water from two 500,000 gallon storage tanks that are nonnally maintained at approximately 90% capacity or more. For this operation both 500 gpm pumps can be run in parallel. The Plant Service Water System provides a seismic Category I source of makeup water and takes suction directly from the Altamaha River. Maximum filling capacity of the Plant Service Water System is approximately 350 gpm.

POTENTIAL EFFECT ON STORED FUEL AND FUEL IN TRANSFER i

For the worst case scenario of a complete bellows assembly failure and the

~ spent fuel pool gates open, the lowesf possible level to which the spent

, fuel pool can drain is 14 ft.9 in. Beloc this level there are no outlets or drains from the pool. The- active section of spent fuel stored in the pool will remain covered with water. Per the Hatch Unit 2 FSAR evaluation in Section 9.1.2.3.1 rapid boiling of the remaining water in the spent fuel pool will not occur. Corrective actions to be taken on low fuel pool level are:

1. reposition of the gates over the canal entrance
2. initiate makeup from condensate storage from the main control room
3. manually align the plant service water system in the reactor building to provide pool makeup 4 continue refilling the pool to normal water level The above scenario however is highly unlikely since it would require failure of both pressure boundaries of the bellows assembly. If the bellows fails, leakage will most likely be detected upon initial filling of the refueling cavity and prior to the fuel transfer operation.

Additionally, due to the welded and backup seal designs, it will not be a catastrophic failure but a leak. This will . permit the operator to secure fuel movement prior to fuel becoming uncovered. Therefore, no analysis has been done to determine the effect on fuel in transfer. Any evaluation of uncovered fuel in transfer is practically a new DBA and any effort would require extensive generic evaluation not completed todate. It has been concluded that any effects on stored fuel have been evaluated in the Hatch Unit 2 FSAR and are of no consequence.

P f 1 Mr. L. T. Gucwa 3 8-GP-12762 September 18, 1984 I

1 TIME TO CLADDING DAMAGE WITHOUT OPERATOR ACTION Cladding damage to fuel in the spent fuel pool will take in excess of 3.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> after the pool has drained to its lowest possible level. This~is the 1

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time calculated for the minimum water level inventory to begin to boil and is reported in Hatch Unit 2 FSAR Section 9.1.2.3.1. , This time period plus the time from initial boiling to cladding failure will . allow for corrective i actions to be taken. )

Damage to fuel in the reactor vessel will not occur since'it is never ]

uncovered and since the shutdown coo-ling system will not be degraded by a i bellows rupture. .

EMERGENCY OPERATING PROCEDURES i

The emergency operating procedures (HNP-1-2087, HNP-1-2085, HNP-2-2087, and i HNP-2-2085) reflect the corrective actions discussed previously and listed )

in FSAR Section 9.1.2.3.1.

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Based on the above, it is 'not considered credible to have a seal failure at

      • Plant Hatch similar to the one that occurrdB at Haddam Neck. Also the

, consequences of such a postulated failure wilknot result in any adverse effects l on plant or public safety. Therefore, no corrective actions are required.

If you have any questions, please advise.

Very truly yours, Original siEned by C. E. feltman SEP 21 19M Gaffour A. Kosi 3,j af Project Engineer

  • ys. fd GAK:KLK:DED:KRL:mmf cc: Southern Company Services, Inc.

W. F. Garner L. 8. Long '

Georgia Power Company (Atl)

J. R. Jordan Georgia Power Company (HNP)

H. C. Nix, Jr.

Manager of Reg. Compl.

s s Superintendent of Plant Engineering & Services bcc: M. Donahue MECHI '

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ulx Interoffice Correspondence Georgia Power d (f

Date: March 21, 1985 '1 i SRC 85-42 Re: .

Plant E. I. Hatch 1

Response to IEN 84-93 From: S. 8. Tipps To: C. T. Jones i

1. Summarv of Root document's subiect(s):

IEN 84-93 concerns potential loss of . water from the refueling d cavity. The Haddam Neck Plant experienced a failure of the pneumatic seal of the- refueling c.avity water seal; This failure drained the cavity in about 20 minutes. The primary concerns i are failure of pneumatic (inflatable) seals.

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Description of Plant Hatch equipment / activities as related to I root document subject (s):

l Plant Hatch does have pneumatic seals in, the Unit 1 to Unit 2 l Fuel Transfer Canal, in the spent Fuel Storage Pool to Reactor ('

Well Gates and in the Dryer /SepRrator Storage Pool to Reactor Well Gate. The Drywell to ~ Reacter Well Bellows and Refueling.

', Bellows are both. flexible metal bellows with no pneumatic seals.

3. Why this is/is not a problem at Plant Hatch:

The potential exists for a seal / bellows assembly failure with a subsequent loss of water from the- refueling cavity. Level switches whi c h will detect and annunciate increased leakage, indicative of seal / bellows failure, are presently installed.

Appropriate NOP and ARP procedures are in place (HNP-1,2-1949.- 1 HNP-1,2-2085 and HNP-1,2-2087) to provide for water restoration- .

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4. Description of actions that have been taken or will be taken: "

. I None required.

l S. Schedule ~ for' completion of any actions required but not  !

completed at time of response:  !

None required.

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Response to EN 84-93 Page 2 (

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Please contact E. M Burkett at extension 2468 if you have any further questions. j l

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/W A S. B. Tipps

Superintendent of i

, Regulatory Compliance SBT/SPES/CR /viz ,

xc: Site QA Manager

  • Secretary Nonlicensed Training Committee Senior Shift Technical Advisor
  • C. R.' Goodman -

4 Documerit File Control (IEN 84-93) s

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