ML19199A677
| ML19199A677 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 07/11/1978 |
| From: | Silver H Office of Nuclear Reactor Regulation |
| To: | Vassallo D Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 7905070248 | |
| Download: ML19199A677 (2) | |
Text
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y"gu Docket F i lA____.,
JUL 111978 LWR +4 File S. Varga H. Silver MEMORANDUM FOR:
D. B. Vassallo, As 'stant Director for Light Water Reactors, DPM FROM:
H. Silver, Proj ect Manager, Light Water Reactors Branch No. 4, DPM THRU:
S. A. Varga, Chief, Light Water Reactors Branch.No. 4, DPM
SUBJECT:
ITEMS FOR THI-2 HEARING BOARD The following items have arisen lately on TMI-2 which may be of interest to the hearing boacd.
(The appeal board is still convened.)
1.
Purge Valve Operability In response to concerns raised by the Containment Syscens Branchi.the Mechanical Engineering Branch has idantified certain requests for additional in-formation regarding operability of ths containnent
. purge valves.
These requests deal with confirms.ary information to more completely document the ability of the containment purge valves to close if they are in use at the time of a LOCA.
Prest:nt technical specifications restrict the tine these valves may be open with the reactor critical to 90 bours per year.
Responses to our requests..are not expected to raise any issues which represent significant safety problems.
~2.
Burnable Poison Rod / Orifice Rod Assemblies At another operating B4W reactor, it was found that
- two burnable poison rod assemblies (BPRA) had been ojected from the core and pieces of several components had bee'a carried into the staan generator inlet plenums.
The reactor was safely shutdown and no damage was done which represented a significant safety issue.
t-
- 3EW concluded that tMs problem was due to wear in the BPRA ball-lock coup 1&ag caused by hydraulic lifting of the BPRA during operation with all four reactor coolant puups.
B&W proposed installation of a BPRA retainer which would provide positive holddown against 6 n.
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D. B. Vassallo JUL 111973 all lift forces, and Met Ed has stated their intention to install this device on all BPRA's.
35W has submitted BOW-1496, BPRA Retainer Design Report, for our approval, but our review is not yet complete.
The same ball-lock device is also employed on orifice rod assemblies (ORA) in BSW reactors.
During the inspection of these devices at another BOW reactor, wear similar to that on the BPRA's was observed.
B4W has concluded that for some plants, including TMI-2, tho ORA's should be removed.
This will require revised thernal-hydraulic analyses for the core, but based on such analysis already completed for other reactors, these are expected to be acceptable.
These analyses fer TMI-2 have recently been submitted and will be reviewed and approved prior to plant startup.
TMI-2 has been shut down for several weeks for correction of operating problems and is not scheduled to start up prior to carly August 1978.
Met Ed at its own risk has already completed the installation of the BPRA retainers and removal of the ORA's.
As noted above, startup will not be permitted prior to approval of all supporting documentation.
3.
Auxiliary Transformar The licensee has inforsad us that recent studies havs shown that for the normal operating range of the gtid, operation with 9. single auxiliary t.ransformer will not provido adequate voltage levels to support operation of balance-of-plant auxiliaries and engineered safety features.
Met Ed proposed both short term and long term corrective actinn which they believe to be in accordance with General Design Critorion 17 and the
- TMI-2 PSAR.
Soo Met Ed letter of May 30, 1978, and LER 78-35/IT attached for additional information.
We have not yet completed our review of this information.
As noted above, TMI-2 is expected to be shut down until August, 1978, by which tine our review should be complete.
. orig:nal signee 37:
H. Silver
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Harley Silver, proj ect Manager Light Water Reactors Branch No. 4 Division of Project Management n-cc:
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