ML20195K111
| ML20195K111 | |
| Person / Time | |
|---|---|
| Issue date: | 01/14/1988 |
| From: | Butler W, Hodges M Office of Nuclear Reactor Regulation |
| To: | Varga S Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20195K113 | List: |
| References | |
| TASK-B-19, TASK-OR GL-86-02, GL-86-09, GL-86-2, GL-86-9, NUDOCS 8801290224 | |
| Download: ML20195K111 (3) | |
Text
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January 14, 1988 MEMORANDUM FOR:
Steven A. Varga, Director Division of Peactor Projects I/II FROM:
Walter P. Butler, Director Project Directorate I-2 Division of Reactor Projects I/II M. Wayne Hodges, Chief Reactor Systems Branch Division of Engineering & Systems Technology
SUBJECT:
CLOSE0HT OF PPA E-04 BWR SINGLE LOOP OPERATION The BWR plant Technical Specifications do not normally permit a plant with two recirculation loops to operate indefinitely with only a single operatina recirculation loop.
MPA E-04 was opened to track all licensee requests for technical specification changes pemitting indefinite single loop operation of the BWR plants. At the time, R. Clark was the lead PM for MPA E-04 and M.
Thadani was the PM for the lead plant, Duane Arnold.
Restrictions on extended single loop operation and operation in natural circulation mode for BWR plants were originally imposed due to concerns related to thermal-hydraulic instability and jet pump vibration problems when operating in the low flow region of the power / flow map.
The operation in the low flow region resulting from single loop operation was thought to have a potential of thewal-hydraulic instability and jet pump vibration problems.
These problems wna followed by the staff under Generic Issue B-19 which was resolved in early 1986. The staff resolutions were comunicated to the licensees in the Generic Letters 86-02 and 86-09. The Generic Letters informed the licensee that operating limitations which provide for detection and suppression of flux oscillations in operating regions of potential instability be imposed on BWR-4,
-5, and -6 plants consistent with the recommendations of the General Electric Service Information Letter 380 (SIL-380).
The BWR-1, -2, and -3 plants with conventional fuel designs should have sufficient stability margins.
The Generic Letters recomended that the owners of the BVR-4, -5, and
-6 plants adopt technical specifications implementing the recommendations of SIL-380 before indefinite operation in single loop mode can be approved by the staff. The licensees were also advised that the approved stability require-ments should be included in future safety evaluations in support of 10 CFR 50.59 determinations for all core reloads and other design or operating modifications which relate to core thermal-hydraulic stability.
The above resolution of Generic Issue B-19 for RWR plants resolyed the technical concerns for creration in single 1000 mode, which it.d to the opening l
' MPA E-04.
The criteria and bases associated with SIL-380 have sperseded those under consideration when MPA E-04 was opened. MPA E-04 is, therefore, no longer required for tracking single loop operation approvals. All such approvals are now being routinely handled by plant specific reviews subject to the resolution identified in Generic Letters 86-02 and 86-09.
These plant specific reviews are initiated only for those licensees that request such
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Accordingly, we recommend that MPA E-04 be closed.
.sw uc Laurence E. Phi lios/
Mohan C. Thadani Lead Reviewer Lead Project Manager NUN h'
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M. Wayne Hodges, Chief Walter R. Butler. Director Reactor System Branch Project Directorate I-2 Division of Engineering and Division of Reactor Projects I/II Systems Technology
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