ML20059M183
| ML20059M183 | |
| Person / Time | |
|---|---|
| Site: | Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png |
| Issue date: | 09/19/1990 |
| From: | Mroczka E CONNECTICUT YANKEE ATOMIC POWER CO., NORTHEAST UTILITIES |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20059M186 | List: |
| References | |
| A08995, A8995, NUDOCS 9010030254 | |
| Download: ML20059M183 (2) | |
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w %....., a, September 19, 1990 Docket No. 50-213 A08995 1
U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555 1
i Gentlemen:
1 Haddam Neck Plant Auxiliary Feedwater System AFW Initiation Event Analysis In a letter dated August 30,1990,II) the NRC Staff granted to Connecticut Yankee Atomic Power Company CYAPCO) a temporary waiver of compliance from Haddam Neck Plant Technical ( Specification 3/4.3.2 "ESF Actuation System Instrumentation,".Section 3 of Tables 3.3-2, 3.3 3, and 4.3-2.
As docu-mented in that letter, the NRC Staff requested that CYAPC0 perform a walk-through of the AFW initiation process to verify that operator action can be performed within the required response times.
Accordingly, CYAPC0 is hereby providing, as Attachment No. 1, documentation of _ the "AFW Initiation Event Analysis" performed by CYAPC0 in response to the NRC Staff request.
The'results of :hese event analyses demonstrate the-reasonableness of CYAPCO's assumption that operators can take manual action in the control room within four (4) minutes to adjust AFW to the full flow required by the safety analysis.
In addition,-the event analyses demon-strated that if the AFW pumps trip on overspeed following automatic initia-tion, local manual action in the Terry turbine building can be taken promptly to establish full AFW flow.
CYAPC0 wishes to point out that the " ANSI /ANS 58.8 Analysis--Case 2,"
detailed on Pages 3 and 4 and illustrated on Figure 2 (both in Attachment No.1), does not meet the guidelines of ANSI /ANS 58.8 since that standard specifies that actions outside the control room cannot be credited for 30 minutes.
However, CYAPCO only committed to perform the analysis follow-l ing the basic format of the standard. We stated in telephone conversations l
with the NRC Staff that we could not meet the specific restrictions on operator actions (i.e.,
no operator action outside the control room 1
(1)
R. Wessman letter to E. J. Mroczka, "Haddam Neck Plant, NRR Temporary Waiver of Compliance Related to the Steam Turbine -Driven Auxiliary feedwater Pumps," dated August 30, 1990.
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U.S. Nuclear Regulatory Commission A08995/Page 2 Sep', ember 19, 1990 credited. for 30 minutes).
Even though: CYAPC0 is= not ' committed to meet ANSI /ANS 58.8 and cannot meet this guideline (as denonstrated in Case 2),
nonetheless, we believe this-situatica is acceptable for two reasons.
First, CYAPCO has committed to dispatching an operator to the Terry turbine-building whenever AFW automatically initiates.
Also, the " Walk Through-Case 2" on Page 5 of Attachment No I demonstrated that an operator.is able -
to reach the Terry turbine building within 2 minutes and start.the Terry turbines within another 2 mhutes 30 seconds (4 minutes, 30 seconds total).
j Since the best estimate analysis performed by-CYAPC0 shows1that full AFW
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flow is not required for 15 minutes, this supports our. conclusion that adequate. time is available even if an operator must restart: and control the AFW pumps' locally from the Terry turbine building.
It should be noted that current operator training for this-event is being performed in the classroom.
The plant-specific simulator is temporarily out of service until modifications are completed.
i Also, in response to a Staff request, CYAPCO. is. forwarding as Attachment i
No. 2, a comparison of some assumptions used in both the design basis analysis and the best estimate analysis of AFW flow needs.
The design'
-i basis (conservative) analysis requires full AFW flow in four minutes from event initiation.
The best estimate (more realistic) case concludes that full AFW flow is not needed until 15 mi'i'.s following event initiation.
4 Please contact us if you have any questbns, j
Very truly yours, I
CONNECTICUT YANKEE ATOMIC POWER COMPANY E. J/Mroczka V Senior Vice President Attachments cc:
T. T. Martin, Region I Administrator L
A. B. Wang, NRC Project Manager, Haddam Neck Plant J.-T. Shedlosky, Senior Resident Inspector, Haddam Neck Plant j
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