ML20006A452
| ML20006A452 | |
| Person / Time | |
|---|---|
| Site: | Trojan File:Portland General Electric icon.png |
| Issue date: | 01/17/1990 |
| From: | Cockfield D PORTLAND GENERAL ELECTRIC CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| IEB-80-06, IEB-80-6, NUDOCS 9001260279 | |
| Download: ML20006A452 (2) | |
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M umme P0ftland General ElectricC0irpsiy g
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David W. Cockfield Vice President, Nuclear January 17, 1990 Trojan Nuclear Plant Docket 50-344
' License NPF-1 l
U.S. Nuclear Regulatory Commission ATTN:
Document Control Desk Washington DC 20555 l
Dear Sir:
i Inspection and Enforcement (IE) Bulletin No. 80-06,
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Rnnineered Safety Feature (ESF) Reset Controls IE Bulletin No. 80-06 discussed an event which identified a potential for automatic position chan6es of safety-related equipment upon reset of ~ ESF actuation signals. The Bulletin required licensees to review applicable _
l drawings and to test as-built instrumentation and controls to verify that
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all associated safety-related equipment remained in their emergency mode upon removal of the. actuation signals. The licensees were to describe corrective actions to be taken if any' safety-related equipment was found not to remain in its emergency mode upon removal of an ESF actuation signal and/or manual resetting of the signal.
Portland General Electric Company (PCE) reported results of its review of applicable Trojan drawings and installation of instrumentation and controls by letter dated June 13, 1980. All safety-related equipment was found to remain in its emergency modo upon removal of ESF signals, with the excep-tion of the steamline drain isolation valves CV-2294, CV-2295,-CV-2296 and CV-2297.
PGE subsequently modifled the control circuit of these steamline drain isolation valves to require a separate positive action by the-operator to reopen these valves when the steamline isolation signal is j
removed. The isolation signal is thus " sealed-in" to keep the valves closed until the operator physically turns the control' switch to the OPEN x
l position.
J Each steamline drain' isolation valve is air operated. Each air.line has two solenoid valves in series, a Train A solenoid valve ~and a Train B solenoid valvo. The steamline drain isolation valves are normally. closed val.ves and would only be open at low power during a startup to drain off condensate. This means that the two solenoids are energized and the.
J solenoid valves and steamline drain isolation valves are closed. With an
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ESF signal prescnt, the solenoids remain energized and the valves remain closed. When the ESF signal clears, the Train A polenoids remain energized; they have the seal-in feature that requires operator action to reset them.
9001260279 900117 PDR ADOCK 05000344 Q
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121 S.W Salmon SUeet Portand. Oregon 97204
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- mn hh Document Control Desk January 17, 1990 Eage 2 During the performance of a periodic test of these valves earlier this year, it was discovered that the Train B solenoids do not have the seal-in feature. A review of design documents revealed that the design modifi-cations made in respons9 to IE Bulletin 80-06 had included the additior. of a seal-in feature to Train A only.
Thus, upon reset of an ESF signal, if the Train B solenoids were doenergized,' control air could flow up to the Train A solenoid valves. As long as the Train A seal-in has not been reset, the Train A solenoid valves will remain energized (i.e..-closed),
control air will not reach the steamline drain isolation valve operator and the steamline drain isolation valves will remain closed.
The absence of the seal-in feature for the Train B solenoid valves is only of significance.if the Train B solenoids are doenergized when the ESF signal clears, and before an operator resets Train A, either the Class 1E power is lost to a Train A solenoid or a Train A solenoid valve.
mechanically fails open allowing control air to open the steamline drain isolation valve. PGE performed a safety evaluation that analyzed the above scenarios and determined that they are bounded by current accident analyses.
To fully meet the intent of IE Bulletin 80-06; however, PCE will install a seal-in feature for the Train B solenoid valves.
This work is presently scheduled for the 1991 refueling outage.
Sincerely,
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Mr. John B. Martin Regional Administrator, Region V U.S. Nuclear Regulatory Commission Mr. David Stewart-Smith State of Oregon Department ~of. Energy Mr. R. C. Barr i
NRC Resident Inspector Trojan Nuclear Plant
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