ML19257B575
| ML19257B575 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 01/17/1968 |
| From: | Zabel C US ATOMIC ENERGY COMMISSION (AEC) |
| To: | Seaborg G US ATOMIC ENERGY COMMISSION (AEC) |
| References | |
| TASK-TF, TASK-TMR NUDOCS 8001170668 | |
| Download: ML19257B575 (3) | |
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P ADVISORY COMMITTEE ON REACTOR SAFEGUARDS UNITED STATES ATOMIC ENERGY COMMISSION Wash 3NGToN. D C.
20545 January 17,, 1968 Ilonorable Glenn T. b,aborg Chairman U. S. Atonic Energy Cornission Washingtori, D. C. 20545
Subject:
ilEPORT ON THREE MILE ISLiND NUCLEAR STATION UNIT 1
Dear Dr. Seaborg:
At its ninety-third meeting, January 11-13, 1968, the Advisory Cotuittee on Reactor Safeguards reviewed the proposal of the Metropolitan Edison Company to construct Three Mile Island Nuclear Station Unit 1.
This project had been considered previously at Subco:nittee meetings held on January 4,1968, in Washington, D. C., and on October 19, 1967, in Hershey, Pa.
During its review, the Coraittee had the benefit of discussions with k.
representatives and consultants of the Matropolitan Edison Company, the Babcock and Wilcox Conpany, Gilbert Associates, Inc., and the AEC Regula-tory Staff. The Committee also had available the documents listed below.
The station is located on Three Mile Island near the east ;nore of the Susquehanna Rlver in Dauphin County, Pennsylvania, about 10 miles south-east of Harrisburg.
Unit 1 is a pressurized-water reactor plant, rated at 2452 W t, and is similar in design to the unit s already approved for construction at the Duke Power Company's Oconee Nuclear Station. Flood protection is to be provided at the site by suitable earth dikes. Tuo natural-draf t cooling towers are to be used for condenser-water cooling.
The emergency core cooling system (ECCS) includes two core flooding tanks, two independent low-pressure systems, and two independent high-pressure systems. Two separate systems are provided for containment cooling. One system consists of three fan-cooling units, and the other consists of two spray systems. The applicant stated that suitable and periodic component and integrated system tests will be performed on these engineered safety I
features. To further insure low containmnt leak rates, a fluid block system and a containment penetration pressurization system are to be prov ided,
f' Operation of the ECCS is initiated automatically by redundant low-pressure j
s ignals from transducers actuated by pressure in the two primary loops.
The Connittee recormends that in the interest of diversity another uethod, p"
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Y lionorable Glenn T. Seaborg January 17, 1968 different in principle from the one proposed, should be added to initiate this function. The diversity thus achieved would enhance the probability that this vital function would be initiated in the unlikely event it is needed.
The output circuit of the proposed reactor protection system consists of a singic d-c circuit (bus) fed from two station batteries. Both feeders must be interrupted to de-energize the bua and drop all rods. Failure to interrupt either feeder, or any other event that prevents de-energizing the single bus, will inhibit dropping all the rods. The Connittee believes this system can and should be revised to correct the deficiency. The revised design should be provided for review prior to installation of the protection system.
The applicant has proposed using certain sisuals from protection instru-ments for control purposes. The Connittee believes that control and protection instru:nentation should be separated to the fullest extent practicabic, and recommends that the applicant explore further the possibility of making safety instrum2ntation more nearly independent of control functions.
Consideration should be given to the development and utilization of instru-nentation for prornpt detection of gross failure of a fuel element.
The applicant described the research and developent vork planned to confirm the final design of the plant. The Corcittee centinues to euphasize the importance of work to assure that fuel-rod failures in loss-of-coolant accidents will not affect significantly the ability of the ECCS to prevent clad melting.
The applicant is continuing studies on the possibic use of part-length rods for stabilizing potential xenon oscillations. Solid poison shims will be added to the fuel elements if necessary to make the moderator temperature coef ficient nore negative at the beginning of core life.
The Regulatory Staff should review the effects of blowdown forces on core internals and the development of appropriate load conbinations and deforma-t ion limits. The Regulatory Staff should also review analyses of the possible effects upon pressure vessel Integrity of themal shock induced by ECCS operation.
The applicant has proposed core barrel check valves between the hot leg and the cold leg to insure proper operation of the ECC9 under all circum-stances. Analytical studies indicate that vibrations will not unseat these valves during normal operation. This point should be verified experimentally.
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Honorable Glenn T. Seaborg January 17, 1968 The Advisory Couaittee on Reactor Safeguards believes that the various items uentioned can be resolved during construction and that the proposed reactor can be constructed at the Three Mile Island site with reasonable assurance that it can be operated without undue risk to the health and safety of the public.
Sincerely yours,
/s/ C. W. Zabel Carroll W. 7.abel Chairman Re fe rences :
- 1. Metropolitan Edison Co:npany letter, dated May 1,1967; Application for Reactor Construction Permit and Operating License, Metropolitan Edison Coupany, Three Mile Island Nuclear Station Unit 1; Preliminary Safety Analysis Report, Vols. 1, 2, and 3.
- 2. Metropolitan Edison Company letter, dated July 21, 1967; kaendment No. 1 to application.
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- 3. M2tropolitan Edison Company letter, dated October 2,1967; Amendment No. 2 to application, including Supplement No. 1, Safety Analysis Report, Vol. 4.
- 4. Metropolitan Edison Co.npany letter, dated Novenber 6,1967; kacud:acnt No. 3 to application, including Supplement No. 2.
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Metropolitan Edison Company let ter, dated Decenber 8, 1967; Amendaent No. 4 to application, including Supplement No. 3.
- 6. Metropolitan Edicon Company letter, dated December 22, 1967; haendment No. S to applicati.oa, including Supplement No. 4.
- 7. Metropolitan Edison Company letter, dated January 8,1968; Amendment No. 6 to application.
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