ML20005E162
| ML20005E162 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 12/18/1989 |
| From: | Sieber J DUQUESNE LIGHT CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| RTR-REGGD-01.097, RTR-REGGD-1.097 NUDOCS 9001040008 | |
| Download: ML20005E162 (6) | |
Text
F 3'
r Whey Power Staton j
ShgunDoort. PA 15077404 J
l l
i.:
fS.$,Nm, om, m2> uns December 18, 1989 l
I 6
U. S. Nuclear Regulatory Commission l
Attn:
Document Control Desk l
Washington, DC 20555
Reference:
Beaver Valley Power Station, Unit No. 1 l
Docket No. 50-334, License No. DPR-66 Response to NRC Regulatory Guide 1.97 Concerns Gentlemen:
A conference call was held on 12/14/89 between C. Anderson, J.
- Joyce, B.
Marcus and J.
Durr of the NRC with K. Grada, T.
Slavic and E. Coholich of Duquesne Light Company.
The enclosure is a summary of the issues discussed during this call and provides supplemental information to support the Beaver Valley I recovery from this refueling outage.
Please contact my office if additional information is necessary on these items.
Very truly yours, a2. k
/[VicePresident D. Sieber Nuclear Group cc:
Mr. J.
Beall, Sr. Resident Inspector Mr. W. T. Russell, NRC Region I Administrator Mr.
P. Tam, Sr. Project Manager Mr.
R.
Saunders (VEPCO)
-Mr.
C.
Anderson (Region I)
Mr. W..Hodges, Director, Reactor Safety, (Region I) f0')
t 9001onooos eg12,g
{DR ADOCK 05o00334 PDC
)
4 ATTACHMENT P g31 i
Problem Descriotion The three wide range steam generator level channels are indicated and recorded on a single recorder.
A failure of the power supply to the recorder would result in a loss of all three wide range level indications.
The three wide range level channels are powered from separate vital busses but are routed together in neutral cable trays from the sensors to the indicating and recording device.
No isolation devices are installed.
Regulatory Guide 1.97 describes steam generator level as a D1 variable.
Safety Imolications As discussed in FSAR Section 7.5.2, Tables 7.5-1 and 7.5-2, the wide range level
- channels, in conjunction with the narrow range level
- channels, are necessary for the assurance of an adequate heat sink.
In
- addition, they are used as diagnostic instrumentation for steam generator tube ruptures and high energy breaks in the main steam and feedwater systems.
The wide range steam generator level indications are referenced in the emergency operating procedures for station
- blackout, low steam generator level and loss of heat sink.
These three procedures, however, are beyond the design bases for Beaver Valley 1 and would not be entered unless there were multiple failures of the emergency diesel generators and/or auxiliary feedwater system in addition to a
loss of both offsite power sources.
Therefore, an additional failure of the wide range level system cannot be applied.
With respect to the design bases events (steam generator tube ruptures and secondary piping failures),
redundant and diverse instrumentation are available for diagnostic purposes as follows:
Steam Generator Tube Ruotures:
Three narrow range level channels per steam generator, two feedwater flow channels per steam generator, two steam flow transmitters per steam generator, three steam pressure channels per steam generator, air ejector radiation monitoring, blowdown radiation monitoring, one auxiliary feed flow channel per steam generator, containment sump level indication and
- alarm, containment temperatures, pressures, radiation and humidity indicators.
Secondary Systems' Ploina Failures:
one auxiliary feedwater flow channel per steam generator, three steam pressure channels per steam generator, two steam and feed flow channels per steam generator, three narrow range level channels per steam generator, containment
- sump, j
pressure, temperature, humidity and radiation indication.
i
c ATTACHMENT PCg3 2 i
Conclusion There are adequate diverse and independent instrumentation
- channels, in accordance with Regulatory Guide 1.97, for accident diagnostics and mitigation of design bases events.
Accidents beyond the design bases, necessitating use of the wide range steam generator level indication would require multiple failures of safety systems in addition to the loss of the wide range level channels.
Issue The wide range level indication system does not meet
Resconse The wide range level system is not a
reactor protection or emergency safeguards actuation circuit as described in IEEE 279-1971 Section 1 " Scope".
Issue The wide range level system, as described in FSAR Section 7.5.2 references " signals obtained through isolation amplifiers".
Resoonse This wording is related to the narrow range protection grade, steam generator level instrument channels.
As stated in FSAR 7.5-2 "Each steam generator (wide range) is indicated and recorded by a
single channel system.
No automatic protectiot-or control functions are provided by these channels."
Please refer to FSAR Tables 7.5-1 and 7.5-2.
Issue The wide range level indication system does not comply with 10CFR50.55a.
Response
IEEE 279-1971 was only applied to reactor protection and emergency safeguards actuating circuits.
The wide range level indication system does not provide input to either of these systems and does not have to meet these requirements.
1 Issue The wide range level indication system does not comply with Regulatory Guide 1.75.
i ATTACHMENT PCg3 3 j
Response
Our letters dated 11/29/85, 10/33/86 and 12/4/89 identified this t
deviation.
Regulatory Guide 1.75 was only implemented on licensees whose safety evaluations were issued after Feb.
1, 1974.
Beaver Valley 1
had its Construction permit issued on June 20, 1970.
In additi%n, the use of narrow range steam generator level indication was accepted in the Appendix "R" safety evaluation report dated January 5, 1983.
Issue The wide range level recorder signal does not have isolators on each input.
Resnonse Adding signal isolators to these inputs would only protect the cabling between the process racks and the control room l
indication.
Since the signal cables are routed in a common neutral
- tray, separation requirements would continue to be an issue.
The re-routing of cable to meet channel separation would require additional analyses to assure that this would not violate other separation criteria such as separation of control and protection circuits.
Issue All three wide range indications appear on a common recorder.
Resoonse The wide range level-indication is also provided to 3 separate computer systemst while they are not 1E, they are battery backed systems.
In addition, wide range level indication is provided on the emergency shutdown panel and locally in the auxiliary feedwater pump room (Table 1).
From a human factor's perspective, it. is beneficial to have all three indications on a common recorder as this would assist the operator in accident diagnostics for design basis events.
The rate of change in level and differential between levels for the three inputs is important for diagnosing steam generator tube ruptures and secondary system line failures.
Issue The wide range steam generator level does not meet Regulatory Guide 1.97.
3
Response
We will evaluate alternative methods for resolving this issue in conjunction with pursuing this deviation through NRR.
L e
e.... -
ATTACHMENT P;g3 4 j
Issue The containment sump level, containment hydrogen concentration and containment pressure indications do not meet the separation criteria.
p
Response
These
-channels have been wrapped with Sil-Temp, within the vertical board, to resolve this issue.
Issue F
Auxiliary Feedwater Flow instruments do not meet the criteria for an Al variable.
Egpoonse Since auxiliary feedwater flow is initiated automatically on all design basis events, in accordance with Regulatory Guide 1.97, it does not have to be a
Type Al variable.
We will revise our submittal to classify this variable as D2.
Auxiliary Feedwater flow indication was previously reviewed on NUREG 0737 Item II.E.1.2 and was considered acceptable on that basis.
Issue The routing of cable in a common neutral tray is subject to single failures.
ResDonse The cabling is rated for 300 volts and 20 amps while the service condition is 45 VDC and 20 Ma, therefore, electrically induced faults are unlikely.
Separation for fire related scenarios does not utilize wide range steam generator level signals and was accepted in our Appendix "R"
safety evaluation report dated January 5,_1983.
Issue Would the operators know how to respond to a loss of wide range steam generator level?
ResDonse As stated previously, sufficient diverse and independent indications are available for design basis accident diagnostics.
l In assurance of adequate heat
- sink, the procedures require maintaining-auxiliary feedwater flow to the steam generators until l
level is in the narrow
- range, therefore, adequate guidance is L
provided.
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