ML19308B693
| ML19308B693 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 01/30/1975 |
| From: | NRC COMMISSION (OCM) |
| To: | Pastore J SENATE |
| References | |
| TASK-TF, TASK-TMR NUDOCS 8001160736 | |
| Download: ML19308B693 (6) | |
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UNITED STATES 8eCretariat NUCLEAR REGULATORY COMM:sslON i
Rec d Q w WASHINGTON, D. C. 20555 s
J '< tl 73 5 e
Honorable John 0. Pastore United States Senate
Dear Senator Pastore:
In connection with the Commission's action yesterday in directing an inspection of piping at all 23 nuclear power plants using boiling water reactors, I thought you might be interested in some additional information.
The impact.of the shutdowns will not be so severe as it might have been since five plants are in a startup phase and are not at full power, and six others are now shut down for other reasons. The names of the plants are listed in an enclosure. The staff calculates that the total impact could amount to about 13,000 megawatts.
An initial analysis indicates there is alternate power available for affected areas of the nation if such is required. The Commission will monitor the situation on a continuing basis.
Enclosed are copies of our public announcement and a report on operating status which reflects estimates of power loss by plant.
I will be pleased to provide any additional information you might desire.
Sincerely, bl Chairman
Enclosures:
As stated I
CC: George Murphy /JCAE Secretariat /
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l UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 No.
75-13 I OR IhNEDIATE RELEASE
Contact:
Frank L. Ingram (Weinesday, January 29, 1975)
Tel.
301/973-771,5 NEW INSPECTIONS OF REACTOR PIPES D1RECTED The Nuclear Regulatory Commission today directed operators
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of 23 boiling water nuclear power plants to determine if there are cracks in piping which is part of the backup emergency core cooling system in the plants.
The operators of the plants will have 20 days in which to shut down and inspect these pipes as well as other specified pipes in the primary and backup cooling systems with an imme-diate oral report to the NRC followed by a written report within 10 days.
It is estimated that each plant will be shut down for about two weeks to make the required inspections.
The action was taken by NRC's Director of Inspection and Enforcement after Commonwealth Edison Company notified the Commission on January 28 that it had found a total of five small cracks in the pipe walls of the two 10-inch diameter core spray lines near where they penetrate the reactor vessel of Unit 2 of the Dresden Nuclear Power Station near Morris, Illinois.
The cracks range from one-eighth to three-fourths of an inch in length on the outside surface.
Small amounts of water were observed on the outside of the pipes, but there was no release of radioactivity to the environment.
The core spray system in boiling water reactors is part of the backup cooling system which would be used to keep the l
reactor core cooled if the flow of primary cooling water to L
the core were interrupted due to a loss-of-coolant accident.
It is.one of several components of the emergency core cooling systemiwhich act independently to supply emergency cooling waterjin the plants.
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. 75-13 In addition, last September smail cracks were found in four-inch bypass lines in the recirculation cooling system at three nuclear plants--Dresden 2 and Quad Cities Unit 2, also operated by Commonwealth Edison, and Millstone Unit 1 in i
Connecticut operated by Northeast Nuclear Energy Company.
Faulty pipe sections were replaced.
On December 13, cracks appeared in a new location in the bypass piping at Dresden Unit 2, prompting the Commission to request utilities to recheck the results of the earlier inspec-tions and conduct new inspections during the next shutdown.
In the meantime, the plants were operated with increased sur-I veillance of monitoring systems for detection of unexpected water leakage.
Following the Commission's mid-December action, small cracks in the bypass lines were found in Quad Cities Units 1 and 2, Peach Bottom Unit 3 in Pennsylvania operated by Philadelphia Electric Company, and Northern States Power Company's Monticello plant in Minnesota.
Eight other plants were found to have no cracks while three plants still are to be inspected at the next shutdown.
The bypass pipes are being replaced at Dresden 2 and Quad Cities 1 and 2.
The Peach Bottom pipe has been repaired and repair also will be made at Monticello.
The bypass pipes connect to larger pipes on each side of a valve and are used to warm the water in the large piping prior to startin2 full circulation.
The bypass lines have no function during actual operation of the reactor.
All of the cracks in the bypass pipes found since September have been near welds in the pipe.
Only in one case (Dresden 2 in September) was there any detectable water leakage.
In all other cases the cracks either were discovered by the ultrasonic testing before penetrating the pipe or the leakage was insignificant.
Recently the Commission established a special study group to examine the cause of small cracks which were found earlier in four-inch auxiliary pipes at six boiling water plants.
Those cracks were in bypass lines in the recirculation cooling system.
The study group now will extend its study to include the cause of the cracks in the 10-inch pipe at Dresden 2.
In addition, the Commission staff dill discuss the matter with the NRC's Advisory Committee on Reactor Safeguards.
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. The NRC study group will examine the metallurgy, water
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chemistry, mode of plant operation, welding procedures, the type of pipe supports used, and the routing of the pipes within the plant.
Consultants from other Government agencies also are participating in the study.
-l Pending completion of the study, che limit on measured water leakage from the plant systems of boiling water reactors of similar design is being reduced.
In the event this limit
. -is exceeded, the plant must shut down inmediately to investi-gate the cause.
All plants are equipped with sensitive moni-toring systems to detect leakage from the coolant systems.
In addition to inspections, these monitoring systems serve as an early warning system against potential problems.
Experts have determined that to date, a characteristic of such pipe flaws is that they propagate slowly and are readily detected by in-struments before they could grow to a size that would be of significance.
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STATUS OF BOILING WATER REACTORS JANUARY 3'0, 1975 I
- i Of 23 plants, six were down:
Dresden 2 Monticello Quad Cities 1 6 2 Big Rock Point Peach Bottom 3*
- Except for the order yesterday Peach Bottom 3 would have gone up to power today.
Whether they do so or not is up to the utility.
v In addition, five ot her plants, which are new, were in'a startup phase:
Brunswick 2 (at or near criticality, still in zero power testing)
Fitzpatrick was at 10 percent power Browns Ferry 2 was about 50 percent Hatch was at about 50 percent Duane Arnold was at about 70 percent
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-'l STATUS OF BOILING WATER REACTOR PLANTS Estimated Operating ) Operational Levels (mie)
Level (MWe Next 3G Oays Absent Licensed Plant Name Utility Location MWe Level 1-30-75 Present Action 1.*ArnolWDubIe l'owa Electric Linn Co., IA 538 360 538
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Light & Power
- 2. Big Rock Point 1 Consumers Power Charlevoix, MI 72 0
72
- 4.
- Browns Ferry 2 TVA Limestone Co., AL 1098 500 1098 5.* Brunswick 2 Carolina Power Brunswick Co., NC 829 0
514
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- 6. Cooper Station Nebraska Public Nemaha Co., NB 778 778 778 Power District
- 7. Dresden 1 Comonwealth Edison Grundy Co., IL 200 180 180
- 3. Dresden 2 Comonwealth Edison Grundy Co., IL 809 0
0
- 9. Dresden 3 Como'nwealth Edison Grundy Co., IL 800 400 400
- 10. *Fitzpatrick Niagara Mohawk Oswego Co., NY 821 82 410
- 11. *llatch 1 Georgia Power Appling Co., GA 786 393 786
- 12. Humboldt Bay Pacific Gas & Elec. Humboldt Co., CA 65 50 65
- 13. La Crosse Dairyland Power Coop.Vernon Co., WI 50 50 50
- 14. Millstone Pt. 1
' Northeast Nuclear New London Co., CT 690 690 690
- 15. Monticello Northern States Pwr. Wright Co., MN 545 0
545
- 16. Nine Mile Pt. 1 Niagara Mohawk Oswego, NY 610 61 0 61 0
- 17. Oyster Creek Jersey Central Ocean Co., NJ 650 650 650
- 18. Peach Bottom 2 PhiladelpHa Elec.
York, PA -
1065 1065 1065
- 19. Peach Bottom 3 Philadelpia Elec.
York, PA 1065 0
1065
- 20. Pilgrim 1 Boston Edison Plymouth, MA 655 196 196
- 21. Quad Cities 1 Commonwealth Edison Rock Island, IL 809 0
809
- 22. Quad Cities 2 Comonwealth Edison Rock Island, IL 809 0
809
,15,356 7.616 12,843
- In power ascension phase not comercial operation e
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