ML20002C994
| ML20002C994 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point File:Consumers Energy icon.png |
| Issue date: | 06/29/1970 |
| From: | Morris P US ATOMIC ENERGY COMMISSION (AEC) |
| To: | Haueter R CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| References | |
| NUDOCS 8101150693 | |
| Download: ML20002C994 (3) | |
Text
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JUN 2 91970 Dockct No. 50-135 Consumers Power Company 212 West Michigan Avenue Jackson, Michigan 49201 Attention:
Mr. Robert L. Haueter Electric Production Superintendent - Nuclear centlemen:
By letter dated February 9, 1970, Consumers Power Company responded to our letter of December 30, 1966, which requested the review of the Big Rock Point emergency core cooling provisions to determine the need, if any, for additional provisions to maintain containment integrity in the event of a major rupture of the primary coolant system.
In our letter, we also suggested that an analysis be performed to determine the impor-tance of emergency core cooling in maintaining containment integrity.
We have ruviewed your letter and the three attachments thereto which describe and support your proposed modifications. These modifications consist nf a second core spray system and other improvements in the engineered safety systems as identified on pages 3 and 4 of your Ictter and pages 5 and 6 of Attachment B.
We recognize that at the present time the system design is inlarge part it. the conceptual stage.
Based on our review to date, we concur in your approach and we have tentatively concluded that:
1.
The proposed redundant automatic low pressure core spray systems and modifications to achieve automatic redundant post-incident containment spray cooling should preserve containment integrity in the event of a major rupture of the primary system.
2.
The proposed core spray system, when approved and oper-ational, will eliminate the need for the temporary core flooding system installed for the centermalt fuel irra-diation program.
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JUN 2 91970 Consumers Power Company 3.
The proposed additional modifications listed on page 5 of Attachment B will result in substantial improvements to the engineered safety systems.
4.
The addition of a new 46 kV power line in March 1968 and the relatively low power output of the Big Rock Point plant (71 We, compared with the total capacity of the j
network, 3600 We) are important considerations in deter-i mining power reliability. This reliability is important to safety because of the dependence on off-sita power for continued operation of a main feedwater pump and other essential equipment in the event of primary system breaks smaller than 0.05 square feet.
To complete our evaluation of the Big Rock Point ECCS capability, we will need the following information and analyses of small primary system breaks:
A description of the feedwater injection connections to a.
the steam drum and the stresses resulting from the intro-duction of cold feedwater.
b.
A list of the sources and the minimum volumes of stored feedwater available for make up to the primary system following small breaks.
A description of the primary system leak detection methods c.
and their sensitivity in terms of break size and time required for detection.
d.
A determination of the largest primary system break that can be tolerated without uncovering the core assuming normal and rapid cooldown procedures, A determination of the largest primary system break that s.
can be tolerated without fuel clad melting assuming plant cooldown without off-site power. Describe the cooldown method. Discuss the operator actions that will be accessary including time availability, further, with respect to criteria to be used in establishing the final design, we request that two points be clarified:
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JUN 2 91970 Consumers Power Company L t
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Will all additions and modifications to facility control and I
safety systems meet the requirements of IEEE-279 " Proposed IEEE Criteria for Nuclear Power Plant Protection Systemst 2.
Will the material specifications, fabrication methods and quality assurance ensure that no heavily sensitized stainless steel will be incorporated into the facility systems?
We believe that the proposed changes will significantly improve the emergency core cooling capability of the Big Rock Point reactor and should be pursued expeditiously. However, pending our review of the information herein requested, we cannot agree at this time that "the addition of this redundant core spray system will maice Big Rock Point equivalent to BWR plants currently authorised for construction, with respect to loss-of-coolant accidents".
We note that prior to putting the modified system into operation, you plan to submit a request for license change. This request should be submitted prior to connet. tion of equipment into existing systems and should include:
1.
the final design of the proposed system; 2.
proposed technical specification changes regarding operation and surveillance of the proposed system: and 3.
a description of the pre-operational tests to be performed prior to plant operation with the modified systems, including acceptance criteria for each test.
Sincerely.
Peter A. Morris, Director Division of Reactor Licensing DISTRIBUTION PDR D. J. Skovholt cc: Judd L. Bacon, Esquire pJ)6cket File R. H. Vollmer Legal Department DR Reading D. L. Ziemann 212 West Michigan Avenue DRL Reading J. J. Shen Jackson, Michigan 49201 Compliance, (2) R. M. Diggs OGC (2) 3, y Handuw DRL DRL
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