ML17054A130
| ML17054A130 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 09/21/1983 |
| From: | Vassallo D Office of Nuclear Reactor Regulation |
| To: | Rhode G NIAGARA MOHAWK POWER CORP. |
| Shared Package | |
| ML17054A131 | List: |
| References | |
| NUDOCS 8310060574 | |
| Download: ML17054A130 (6) | |
Text
September 21, 1983 Docket No. 50-220 DISTRIBUTION
'ocket File, JMTaylor NRC PDR NSIC Local PDR ACRS (10)
Mr. G.
K. Rhode ORB¹2 Reading Gray File Senior Vice President DEisenhut Niagara Mohawk Power Corporation OELD 300 Erie Boulevard i<est ELJordan
- Syracuse, New York 13202 RKermann EReeves
Dear Mr. Rhode:
VNoonan SNorris
SUBJECT:
COMPLETION OF REVIEtl ON CONTAINMENT ISOLATION DEPENDABILITY BY DEMONSTRATION OF CONTAINMENT PURGE AND VENT VALVE OPERABILITY (MPA B-24),
TMI ITEM II.E.4.2 (POS.
6)
Re:
Nine Mile Point Nuclear Station, Unit I In our letter of November 29, 1978, we identified the generic concerns of purging and venting of containment to all operating reactor licensees and requested your response to these concerns.
Our review of your response was interrupted by the TMI accident and its demands on staff resources.
Consequently, an Interim Position on containment purging and venting was transmitted to you by letter dated October 22, 1979.
You were requested to implement short-term corrective actions to remain in effect pending completion of our longer term review of your response to our November 28, 1978 letter.
One of the remaining interim corrective actions (and the subject of this letter) still in place while our longer term review is being completed is to:
"Maintain the containment purge and vent isolation valves closed whenever the reactor is not in the cold shutdown or refueling mode until such time as you can show that:
a.
All isolation valves greater than 3" nominal diameter used for containment purge and venting operations are operable under the most severe design basis accident flow condition loading and can close within the time limit stated in your Technical Specifica-tions, design criteria or operating procedures.
The operability of butterfly valves
- may, on an interim basis, be demonstrated by limiting the valve to be no more than 30'o 50'pen (90'eing full open).
The maximum opening shall be determined in consultation with the valve supplier.
The valve opening must be such that the critical valve parts will not be damaged by DBA-LOCA loads and that the valve will tend to close when the fluid dynamic forces are introduced."
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Mr. G.
K. Rhode Your letter of December 17, 1979 provided your commitment regarding conformance with this Interim Position pending completion of our long-term review of valve operability.
We have completed our review of the information submitted in your letters dated December 17, 1979 and January 29, 1982, concerning the operability of the valves used in the containment vent and purge system at Nine Mile Point.
Our Safety Evaluation is enclosed.
We find the information submitted failed to demonstrate the ability of these valves to close against the buildup of containment pressure in the event of a
LOCA.
For this reason, the purge and vent valves should be sealed closed in accordance with SRP Section 6.2.4, II.6.f whenever the reactor mode switch is in the startup/hot standby or run mode.
Furthermore, these valves should be verified to be closed at least once every 31 days.
Therefore, pursuant to 10 CFR 50.54(f), you are requested to inform us under oath and affirmation in writing within 15 days of receipt of this letter:
1.
Your assessment of the operability of your purge and vent valves in light of the concerns outlined in Enclosure 1,
and 2.
Whether or not you intend to maintain the purge and vent valves sealed closed in accordance with Standard Review Plan Section 6.2.4, II.6.f and to verify them to be closed every 31 days whenever the reactor is not in the cold shutdown or refueling mode until such time as you submit acceptable information that demonstrates that your purge/vent valves will operate in the event of a DBA-LOCA.
This information will enable the Commission to determine whether or not further action should be taken to modify, suspend, or revoke your license.
The reporting and/or recordkeeping requirements contained in this letter affect fewer than ten respondents; therefore, OMB clearance is not required under P.L.96-511.
Since'rely, Original signed by/
Enclosure:
As stated Domenic B. Vassallo, Chief Operating Reactors Branch ¹2 Division of Licensing cc w/enclosure:
See next page
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V Mr. G.
K. Rhode Your letter of December 17, 1979 provided your commitment regarding conformance with this Interim Position pending completion of our long-term review of valve, operability.
We have completed our review of 'the information submitted in your letters dated December 17, 1979 and,January 29, 1982,, concerning the operability of the valves used in"the containment
'vent and purge system at Nine Mile Point.
Our Safety Evaluation is enclosed.
I We find the information submitted failed to demonstrate the ability of these valves to close against the bui'ldup of containment pressure in the event of a
LOCA.
For this reason, the purge and vent valves should be sealed closed in accordance with SRP Section 6.2.4,,'II.6.f whenever the reactor mode switch is in the startup/hot standby. or run "mode.
Furthermore, these valves should be verified to be closed at least once every 31 days.
Therefore, pursuant to 10 CFR 50.54(f), you are requested to inform us in writing within 15 days of receipt of this letter:
1.
Your assessment of the operability of your purge and vent valves in light of the concerns outlined in Enclosure 1,
and 2.
Whether or not you intend to maintain the purge and vent valves sealed closed in accordance with Standard Review Plan Section 6.2.4, II.6.f and to verify them to be closed every 31 days whenever the reactor is not in the cold shutdown or refueling mode until such time as you submit acceptable information that demonstrates that your purge/vent valves will operate in the event of a DBA-LOCA.
This information will enable the Commission to determine whether or not further action should be taken to modify, suspend, or revoke your license.
The reporting and/or recordkeeping requirements contained in this letter affect fewer than ten respondents; therefore, OMB clearance is not required under P.L.96-511.
Sincerely,
Enclosure:
As stated Domenic B. Vassallo, Chief Operating Reactors Branch ¹2 Division of Licensing cc w/enclosure:
See next page DL:ORB¹2 D '
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