ML25196A441
| ML25196A441 | |
| Person / Time | |
|---|---|
| Site: | Midland |
| Issue date: | 11/18/1976 |
| From: | Moeller D Advisory Committee on Reactor Safeguards |
| To: | Rowden M NRC/Chairman |
| References | |
| Download: ML25196A441 (1) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION ADVISORY COMMITTEE ON REACTOR SAFEGUARDS WASHINGTON, D. C. 20555 Honorable Marcus A. Rowden Chairman
- u. s. Nuclear Regulatory Commission Washington, DC 20555 November 18, 1976
Subject:
SUPPLEMENTAL REPORI' ON MIDLAND PLANT UNITS 1 AND 2
Dear Mr. Rowden:
In response to a request from Chairman D. M. Head of the Midland Atomic Safety and Licensing Board, the Advisory Committee on Reactor Safeguards has reviewed the record pertaining to the Midland Plant Units 1 and 2 as reported in its letter of June 18, 1970. The items listed below are those items referred to in its paragraph on nother problems related to large water reactorsn which had been previously nidentified by the Reg-ulatory Staff and the ACRS,n and which the Committee considered applicable to the Midland Plant. Following each item, the Committee has included an aili)lifying statement based on ACRS reports on other similar conmer-cial nuclear reactor power plants which had been reviewed during the months prior to the Committee's review of the Midland Plant. Copies of the referenced ACRS reports are attached.
- 1. Separation of protection and control instrumentation - The Applicant proposed using signals from protection instruments for control purposes.
The Committee believed that control and protection instrumentation should be separated to the fullest extent practicable, and recommended that the Applicant explore further the possibility of making safety instrumentation more nearly independent of control flmctions.
(Three Mile Island, 1/17/68).
- 2. Vibration and loose parts monitoring - The Committee reccmmended that the Applicant study possible means of in-service monitoring for vibration or the presence of loose parts in the reactor pressure vessel as well as in other portions of the priinary system, and implement such means as found practical and appropriate.
(Palisades, 1/27/70).
- 3. Potential for axial xenon oscillations - The Applicant was continuing studies on the possible use of part-length rods for stabilizing potential xenon oscillations. Solid poison shims were to be added to the fuel elements if necessary to make the moderator temperature coefficient more negative at the beginning of core life.
(Three Mile Island, 1/17/68).
951
Honorable Marcus November 18, 1976
- 4. The behavior of core-barrel check valves in normal operation - 'lhe Applicant had proposed core-barrel check valves between the hot leg and the cold leg to insure proper operation of the ECCS under all circum-stances. Analytical sttrlies had indicated that vibrations would not unseat these valves during normal operation. The Conmittee desired that this point be verified experimentally.
(Three Mile Island, 1/17/68).
- 5. The potential consequences of fuel handling accidents - The Committee believed that further study was required with regard to potential releases of radioactivity in the unlikely event of gross damage to an irradiated subassembly during fuel handling and the possible need for a charcoal filtration system in the fuel handling building. The Committee reconmended that this matter be resolved in a manner satisfactory to the Regulatory Staff.
(Hutchinson Island, 3/12/70).
- 6. The effects of blC1wdown forces on core internals - 'lhe Committee recommended that the Regulatory Staff review the effects of blowdown forces on core internals and the developnent of appropriate load combi-nations and deformation limits.
(Three Mile Island, 1/17/68).
- 7. Assurance that LOCA-related fuel rod failures will not interfere with ECCS function - The Committee desired to emphasize 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.
(Three Mile Island, 1/17/68}.
- 8. The effect on pressure vessel integrity of ECCS induced thermal shock - The Committee recommended that the Regulatory Staff review anal-yses of possible effects, upon pressure-vessel integrity, arising from thermal shock induced by ECCS operation.
(Oconee, 7/11/67).
- 9. Environmental qualification of vital equipnent in containment - The Committee recommended that attention be given to the long-term ability of vital components, such as electrical equipnent and cables, to with-stand the environment of the contairnnent in the unlikely event of a loss-of-coolant accident.
(Palisades, 1/27/70).
- 10. Instrumentation to follC7w the course of an accident - This item related to the developnent of systems to control the buildup of hydrogen in the containment, and of instrumentation to roonitor the course of events in the unlikely event of a loss-of-coolant accident.
(Hutchinson Island, 3/12/70).
952
Honorable Marcus November 18, 1976
- 11. Improved quality assurance and in-service inspection of primary sys-ten - The Conmittee continued to emphasize the importance of quality as-surance in fabrication of the primary system as well as inspection during service life, and recommended that the Applicant implement those improve-ments in quality practical with current technology.
{Oconee, 7/11/67).
Sincerely yours, Dade w. Moeller Chairman Attachments:
- 1. Request from Chairman D. M. Head, AS&LB, dated 10/14/76
[*] 2. Report on Midland Plant Units 1 & 2,
[*] See pages dated 6/18/70
- 3. Report on Hutchinson Island Unit No. 1, See pages dated 3/12/70
- 4. Report on Palisades Plant, dated 1/27/70 See pages
- s. Report on Three Mile Island Nuclear See pages Station Unit 1, dated 1/17/68
- 6. Report on Oconee Nuclear Station, See pages Units 1, 2, and 3, dated 7/11/67 953 943-948, Vol. II 790-793, Vol. II 1188-1191, Vol.
1637-1639, Vol.
1154-1156, Vol.
II I II II