ML19254G128
| ML19254G128 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 03/05/1980 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML111090060 | List:
|
| References | |
| FOIA-80-515, FOIA-80-555 NUDOCS 8004100835 | |
| Download: ML19254G128 (1) | |
Text
Enclosure TMI-l SER SUPPLEffEtiT Status Recort, Page Cl-10, Additional Items, No. 8:
In Amendment 12. Met-Ed provided additional infomation to our concern with a pipe rupture in the EF4 pump discharge line. The TMI emergency feedwater system does not meet all our present criteria, specifically, the system is not designed as a high energy system. The licensee points out that their EF4 system is not used for startup and shutdown, but functions only under emergency and periodic testing conditions, thus reducing the probability of a pipe rupture. The licensee further indicates that the nomal system operating stresses are substantially less than the minimum yield strength of the system oiping, and therefore, a double-ended high energy pipe break is extremely improbable.
In addition, Met-Ed has agreed to perfom a volumetric nondestructive exa-mination ('40E) prior to restart of 10 welds in the system piping with the highest combined stresses to verify that no undesirable flaws exist. We have also noted that 5&W plants with the once-through steam generator have not experienced any water hammer phenomena in the EF4 system which could N#4I AND impose additional stresses.f Qvt1/4/4 bey Based on the above d::i;r '::tmt,A
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FEB 2 81980 MEMORANDUM FOR: Harley Silver, Project Manager TMI-1 Restart FROM:
Jared Wermiel Auxiliary Systems Branch, DSS THRU:
Gerald Mazetis, Section Leade Reactor Systems Branch, DSS
SUBJECT:
TMI-l RESTART REVIEW, AUTOMATIC INITIATION OF EMERGENCY FEE 0 WATER (EFW)
As part of the restart requirements included in the Order for.TMI-1, Met-Ed is required to implement Short Term Lessons Learned, NUREG-0578 prior to restart. Recently issued Orders to all operating pWR licensees (except Met-Ed) exempt them from compliance with Lessons Learned item 2.1.7.a.
Automatic. Initiation of Auxiliary Feedwater. No schedule for its implemen-tation has oeen established. Since Met-Ed did not receive this notifica-tion, we have assumed that they are required to implement the short term requirements of 2.1.7.a prior to restart.
Requirement 2 of item 2.1.7.a specifically states that automatic ER4 initia-tion snall meet the single failure criterion to prevent loss of system function. Met-Ed has committed to provide single failure proof auto initia-tion signals for EFW pump actuation prior to restart. However, the staff interpretation of " system function" includes automatic opening of the ER4 control valves. This interpretation presents a problem to TMI-1 (and a numoer of other B&W plants) in that EFW system flow control is provided through the Integrated Control System (ICS) which is subject to single failures that could prevent automatic delivery of feedwater even if the ?.FW pumps are properly actuated.
Met-Ed has comitted to eventually upgrade the EFW system to meet all safety grade requirements and eliminate the ICS dependency of the EFW control valves.
However, this modification involves procurement of certain long lead time equipment (nuclear class valves and instrumentation) and Met-Ed states that the equipment cannot be installed prior to the presently projected restart date. They indicate that delivery and installation of these items is not expected before mid-1981. The licensee proposes, therefore, to install the safety grade system modifications at the first refueling outage after restart.
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Nb Harley Silver gs28 In the interim, Met-Ed has stated in the Restart Report that they will make certain procedural and hardware modifications to enhance EFW system reliability prior to restart. These modifications include the addition of a de powered manual backup EFW control valve operating station in the control room fully independent of ICS (although steam generator level indication is not separated from ICS). This station enhances operator capability to control EFW flow in the event of an ICS failure. Plant operating and emergency procedures have been revised to instruct the coerator on use of this new manual station. To further enhance system availability, a backup air compressor powered from vital busses and a passive air reservoir have been added to assure air supply to the flow control valves, and thereby provide the capability to modulate them as necessary.
In addition, recently approved analyses by B&W indicate that a 20 minute delay in EF4 initiation in B&W plants including TMI-l will not compromise core cooling capability. This time would allow an operator to assume local manual, control (outside~ the control room) of EP4 at the valves if needed.
With the licensee's stated schedule problems, it appears that delay in restart is imminent unless relief from 2.1.7.a is allowed. A decision on applicability to TMI-l of the previous exemptions to 2.1.7.a is therefore requested.
Jared Wermiel Auxiliary Systems Branch Division of Systems Safety cc:
D. Eisenhut R. M:ttson R. Nilmer T. Telford V. Benaroya P. Matthews R. Reid C. Long H. Silver R. Fitzpatrick S. Newberry B. Boger