ML19210A667

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Requests Info Re Reactor Cavity Annulus Seal Ring & Associated Biological Shielding Over Reactor Vessel Cavity by 780222.Addressed to All PWR Licensees Except Trojan
ML19210A667
Person / Time
Site: Indian Point, Arkansas Nuclear, Crane  Entergy icon.png
Issue date: 02/02/1978
From: Stello V
Office of Nuclear Reactor Regulation
To:
ARKANSAS POWER & LIGHT CO., CONSOLIDATED EDISON CO. OF NEW YORK, INC., METROPOLITAN EDISON CO.
References
GL-78-3, NUDOCS 7910300697
Download: ML19210A667 (1)


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UNITED STATES 8i NUCLEAR REGULATORY COMMISSION

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,, E WASHINGTON. D. C. 20555

,g& fI ts,, y j February 2,1978 DU $0 All PWR Licensees (except for Trojan)

Gentl emen:

During the course of responding to the staff's review of an application for license amendment on the Trojan Nuclear Plant, the licensee infomed the NRC that the reactor cavity annulus seal ring (used as a water seal during refueling operations, and not removed during normal operations) and associated biological shielding over the reactor vessel cavity could become missiles in the event of a loss of coolant accident (LOCA) pipe break inside the react,e vessel cavity. At the Trojan Nuclear Plant, these missiles could affe'.t the ability of the control rods to shut down the reactor. From our prelimina7 evaluation of the information provided to the NRC staff by the licenses, the Portland General Electric Company and by Westinghouse, Combustion Engineering, Babcock & Wilcox and Bechtel in telephone di:. ssions on January 25 and 26,1978, it appears that this problem could occur in other PWR facilities such as yours and could potentially pose a threat to the health and safety of the public in the event of a LOCA.

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 Regulation, Nuclear Regulatory Commission, Washingterb DC 20555, within 20 days of the date of this letter, i.e., February 22, 1978, the following information: (a) a statement as to whether the cavity annulus seal ring in your facility is left in place during normal operation or if biological shielding is installed in the reactor cavity annulus and, if the answer to (a) is yes; (b) when you will determine whether the cavity annulus seal ring or biological shielding could become a missile in your facility, and (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 list.

Sincerely,

.#M 1490 112 VictorSIllo Jr., Director Division of 0-4 rating Reactors Office of Nuclec. Reactor Regulation A

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