ML20043B277

Advises of Mod to Original Commitment & Plans to Store Seal Ring in Original Storage Location During Plant Operations, Per 790606 Ltr.Mod Minimizes Personnel Exposure & Enhances Seal Plate Leak Tightness Due to Less Handling

ML20043B277
Person / Time
Site:	Crystal River
Issue date:	05/18/1990
From:	Beard P FLORIDA POWER CORP.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20043B278	List: ML20043B277 ML20043B283
References
3F0590-10, 3F590-10, NUDOCS 9005250195
Download: ML20043B277 (2)

Text

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l x .. w Ep n 2 C 0 R P O R AT l0 N c May.18,: 1990-3F0590-10 4

U.S.ENuclear-Regulatory Commission

/J.tn: Document Control Desk o

Washington, D.'.C. 20555

Subject:

. Crystal River, Unit 3

-Docket No. 50-302-  :

Operating: License No. DPR-7;2 Reactor. Cavity Annulus Seal Ring Storage l

, References (copies attached):-

)

1. . Letter Victor Stello, Jr. (NRC) to All PWR Licensees (except s for' Trojan), dated February ~2, 1978

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-2.- Letter;W.P. Stewart (FPC) to NRC, Response to NRC's 2/2/78  :

letter,Jdated February-22, 1978  !

3. Letter W.P. Stewart -(FPC) to Robert W. Reid (NRC), " Reactor 'i

- Cavity'~ Annulus Seal Ring Support", dated June-6, 1979  ;

4.. Letter Robert W. Reid (NRC) .to W.P. Stewart (FPC), " Reactor Cavity Seal Ring Generic Issue (PWR)", dated September 11, 1979

Dear Sir:

-In response to an NRC letter dated February 2, 1978 (Reference 1),

Florida a Power Corporation '(FPC) committed to store the reactor- e cavityJannulusiseal ring on the floorLof the containment. building fduring plant operations until FPC and the NRC approved a new seal t ring support system (Reference 3). .The - 'NRC by letter dated i

. September 11, 1979 accepted this commitment (Reference 4).

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The' original concern identified the seal ring as a potential y!

q missile during a Loss Of Coolant Accident (LOCA). Calculations

~, performed' at - that - time showed that the. seal ring ' missile could

-damage 'the control rod drive shroud and the control rod drives. ,

-Three postulated pipe failures were analyzed that could result in '

F," ' , pressurization of the reactor vessel cavity - hot leg break, cold leg. break, and-core flood line break. p t

9005250195 900519 hDR ADOCK 05000302 01 PDC \\

GENERAL OFFICE: 3201 Thirty fourth Street South

• P.o. Bc,x 14042

• St. Petersburg, Florida 33733 * (813) 866-5151

. A Florida Progress Company i

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'May 18, 1990

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3F0590-10 1 Page-2 Since that time, the probability of large pipe breaks in the primary coolant system-has been determined to be sufficiently low j such that dynamic effects associated with postulated pipe breaks need not be a design basis as stated in Amendment No. 89 of FPC's Facility Operating License. In addition, re-analysis by B&W of the core flood line break demonstrates that the seal ring impact as a missile on the control rod drive shroud and control rod drives is loss than originally calculated and no damage occurs to-the ,

control rod' drives.

Therefore, based - on the above, FPC is modifying its original commitment (Reference 3) and plans to store the seal ring in its original storage location just above the reactor vessel flange ,

during plant operations. This will minimize personnel exposure, enhance seal plate leak tightness due to less handling, and save

" critical path" manhours. ,

If you have any questions regarding this subject, please contact Mr. Rolf C. Widell, Director, Nuclear Operations Site Support at (904)~563-4529.

Sincerely,

/

.M Beard, Jr.

Seni r Vice President Nuclear-Operations PMB/GMF

-Attachments xc: Region Administrator, Region II Senior Resident Inspector i

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.=7 a '- '4,J NUCLEAH HEGULATOHY cOMMisslON

!!! wAswinoToN. o. C. 20%6 A *[. . a February 2,1978 DOM "I py All PWR' Licensees (except for Trojan) p erg /)fd, 7

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Gentlemen: .

=During the course of responding to the staf - -ces.1 an application for license amendment on the Trojan Nuclear Plant, the licensee informed the NRC that the reactor cavity annulus seal ring (used as a water seal during refueling operations, and not removed during normal operations) ,, g -

and associated biological shielding over the reactor vessel cavity could 1g',.

jr become missiles in the event of a loss of coolant accident (LOCA) pipe break inside the reactor-vessel cavity. At the Trojan Nuclear Plant, these P missiles could affect the ability of the control rods to shut down the reactor.- From our preliminary evaluation of the information provided to the NRC = staff by the licensee, the Portland General Electric Company and by Westinghouse, Combustion Engineering, Babcock & Wilcox and Bechtel in telephone discussions on January 25 and 26,1978, it appears that this problem could occur in other PWR facilities such as yours and could 7 potentially pose a- threat to the health and safety of the public in the Ay event of a LOCA. fr.r.

Therefore, pursuant to 10 CFR 50.54(f) of the Commission's regulations,  ;

.you are hereby requested to deliver to the Office of Nuclear Reactor DC 20555, within

(- Regulation, Nuclear Regulatory Connission,

~ 20 days of the date of. this letter, i.e., February Washington 22,, 1978, _the _following information: (a) a statement as to whether the cavity annulus seal- ring in your facility is lef t in place during normal operation or if biological .-

shielding is installed in the reactor cavity annulus and, if-the answer ;M;d to (a) is yes; (b) when you will detemine whether the cavity annulus seal ring or biological shielding could become a missile in your facility, and Pl!P" (c) a cescription of what you plan to do, and when, if the- problem is found [ ,'

at your facility and (d) justification for continued operations until the .,

problem has been resolved, such justification to support why continued  ;

operation will not create undue risk to the health and safety of the public. -.

A copy of this letter is being provided to each licensee's current service 1ist. 'f Sincerely, ,".

.' M Victor Sdllo., Jr., Director L

Division of Operating Reactors .l Of fice of Nuclear Reactor Regulation r.~

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