ML18081A730
| ML18081A730 | |
| Person / Time | |
|---|---|
| Site: | Salem  |
| Issue date: | 10/30/1979 |
| From: | Schwencer A Office of Nuclear Reactor Regulation |
| To: | Librizzi F Public Service Enterprise Group |
| References | |
| NUDOCS 7912100410 | |
| Download: ML18081A730 (8) | |
Text
'
\\ \\ \\
I I
-e OCTOBER 3 0 1979 Docket.No. 50-272 Mr~ F. P. Librizzi, General Manager Electric Production Public Service Electric and Gas Company 80 Park Place, Room 7221 Newark, New Jersey 07101
Dear Mr. Librizzi:
RE:
Contaimnent Purging and Venting During Normal Operation By letter dated November 28, 1978, the Commission (NRC) requested all licensees of operating reactors to respond to generic concerns about containment purging or venting during normal plant operation.
- The generic concerns were twofold:
( 1)
(2)
Events had occurred where licensees overrode or bypassed the safety actuation isolation signals to the containment isolation valves.
These events were detennined to be abnormal occurrences and repor.ted to Congress in January 1979.
Recent licensing reviews have required tests or analyses to show that containment purge or vent valves would shut without degrading containment integrity during the dynamic loads of a design basis loss of coolant*
accident (DBA-LOCA).
The NRC position of the November 1978 letter requested that licensees take the fol lowing positive actions pending completion of the NRC review:
(1) prohibit the override or bypass of any safety actuation signal which would affect another safety actuation signal; the NRC Office of Inspection and
- Enforcement would verify that administrative controls prevent improper manual defeat of safety actuation signals, and (2) *cease purging (or venting) of containment or limit purging (or venting) to ari absolute minimum, not to exceed 90 hours0.00104 days <br />0.025 hours <br />1.488095e-4 weeks <br />3.4245e-5 months <br /> per year. Licensees were requested to demonstrate (by test or by test and analysis) that containment i.solation valves would shut under postulated DBA-LOCA condition. The NRC positions were amplified by citation (and an attached copy} of our Standard* Review Plan (SRP) 6.2.4 Revision 1 and the associated Branch Technical Position CSB 6-4, which have effectively classed the purge and vent valves as 11active 11 invoking* the operability assurance program of SRP 3e9.3.
fORIVI 3_18 (9-76) NRCM 0240
-C::-u.s. GOVERNMEf-JT PRINTING OFFICE: 1979-289-369.*.
Mr. F. The NRC staff has made site visits to several facilities, has met with licensees at Bethesda, Maryland; and has held telecon conferences with many other.
licens.ees and met with some valve manufacturers.
During these discussions, the NRC staff has stressed that positive actions must be taken as noted above to assure that containment integrity would be maintained in the event of a DBA-LOCA.
As a res.ult of these actions, we have learned from several licensees that at least three valve vendors have reported that their valves may not close against the ascending differential pressure and the resulting dynamic loading of the design basis LOCA.
All identified licensees who are affected have proposed to maintain the valves in the closed position or to restrict the angular opening of the valves whenever primary containment integrity is required pending a re-evaluation which shows satisfactory valve performance under the DBA-LOCA condition can be provided.
Recently, a report under 10 CFR Part 21 was.received by the NRC from the manufacturer _of butterfly valves which are ins ta 11 ed in the primary containment at the Three Mile Island Unit 2 Nuclear Station. These butterfly valves are -
used for purge and exhaust purposes and are required to operate during accident conditions. The report discusses the use of an unqualified solenoid valve for a safety-related valve function which requires operation under accident conditions. The solenoid valW'.e is used to pilot control the pneumatic valve
.. actuators which are installed on the containment ventilation butterfly valves at this facility. Your re-evaluation of valve performance for conditions noted in the previous paragraph must consider the concerns identified in IE Bulletin 79-0lA.
As the NRG review progresses, licensees which might have electrical override circuitry problems are being advised not to use the override and to take compensatory interim measures to minimize the problem.
In light of the information gained during our reviews of your submitta1s dated January 30, August 30, and October 5, 1979 and the information cited above, we believe an interim commitment from you is required at this time. This is the case, even though you may have proposed Technical Specification changes or other long or short-term measures, which we are reviewing.
For your use, we
- ,have provided as an attachment an interim NRC staff position.
In addition, our recently developed "Guidelines for Demonstration of Operability of Purge and Vent Valves" were provided by separate letter to licensees of each.
operating -reactor. This letter in no way relaxes any existing licensing requirements for your facility.
. OFFICE.**. -*... *-... :.*,...,,, -. -,,, _,_,,...': *,*. * - * * * * * *.. * *.,,_.:.*, *
- * * * * * * * * * * * * * * **- * *- * * '* *~- * * *** * *- '*' * - *. '. - ... '.'
SURNAME *.. -......*. -.* ' -. ' : - '.... " ' - ' - - - ' *'..
. '. '*:..... ' ' "~-.~ -...
'**, ' '.*.. ' ' ; * '.*. ' ;. ' ' * '. '...... ' - '.. ' '. ' '. '. '. ' ' - '*. ' '~ '
DAT~******-***********'******-**-*****--............... *............ *...................................... :*... ;'.
NRC FORM 318 (9*76) NRCM 0240 fru.s. GOVERNMENT PRINTING OFFICE: 1979-289-369
Mr. F. P~ Librizzi Because of the potential adverse effects on the public health and safety
. which could result from the postulated DBA-LOCA while operating with open purge or vent valves, we believe your prompt response to this letter is required. In accordance with 10 CFR 50.54f, you are requested to inform us in writing within 45 days of receipt of this letter of your commitment to operate in conformance with the enclosed interim position and to provide us with information which demonstrates that you have initiated the purge and vent valve operability verification on an expedited* basis. The information provided in your response will enable us to determine whether or not your license to operate Salem Unit No. l should be modified, suspended, or revoked.
Enclosure:
Interim Position for Containment.
Purge and Vent Valve Operation cc w/enclosure:
See next page Sincerely, Original Sicr.,~d By.
A. Schw~ncer, Chief Operating Reactors Branch tfl Division of Operating Reactors DISTRIBUTION:
Docket NRC PDR Local PDR ORB-1 Reading NRR Reading ASchwencer CParrish t~Ross EAReeves Attorney, DELO I&E (3)
GLa inas*
JRBuchanan TERA ACRS (16)
OFFICE~.OOHJ~t..17.....POR:.Q,RS(t..... D.OR.:.'.
suRNAME~.l~RQ-. fp;~......
~l:\\REl~$...... ASch. nc;er........................................................
DATE~.19/~7/?9........ JQ/. /?9.......J.Qf'Y.1./7.9............................................................
NRC FORM 318 (9-76) NRCM 0240
-f:ru.s. GOVERNMENT PRINTING OFFICE: 1979-289-369
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. ~0555
- Docket No *. 50-.272 Mr. F. P. Librizzi, General Manager Electric Production
_October 30, 1979 Public Service Electric and G~s Company 80 Park Place, Room 7221
- Newark:, New Jersey 07101
Dear Mr. Librizii:
RE:
Containment Purg~ng and Venting During Normal Operation By letter dated November 28, 1978, the Commission (NRC) requested all licensees of operating reactors to respond to generic concerns about containment purging or. venting during normal plant operation. The generic concerns were twofold:
(1) _Events had occurred where license~s overrode or bypassed the safety actuation isolation signals to the containment isolation valves.
These events were detennined to be abnormal occurrences and reported to Congress in January 1979.
(2)
Recent licensing reviews have required tests or analyses to show that containment purge or vent va.lves would shut without degrading containment integrity during the dynamic loads of a design basis loss of coolant accident (DBA-LOCA).
- The NRC position of the November 1978 letter requested that. licensees take, the fol lowing positive actions pending completion of the NRC review:
(l) prohibit the override or bypass of any safety actuation signal whi'ch would affect another safety actuation signal; the NRC Office of Inspection and Enforcement would verify that administrative controls prevent improper manual defeat of safety actuation signals, and (2) cease purging (or venting) of containment or limit purging (or venti_ng) to an absolute minimum, not to exceed*
90 hours0.00104 days <br />0.025 hours <br />1.488095e-4 weeks <br />3.4245e-5 months <br /> per year. Licensees were requested to demonstrate (by test or by test and analysis) that containment isolation valves would shut under postulated DBA-LOCA.condition.
The NRC positions were amplified by citation (and an attached copy) of* our Standard Review Plan (SRP) 6.2.4 Revision land the associated Branch Technical Position CSB 6-4, which have effecttvely classed the purge and vent valves as 11active 11* invoking the operability assurance program of SRP 3.9.3.
Mr. F.
- October 30, 1979
- The NRC staff has made site visits to several facilities, has met with licensees at Bethesda, Maryland, and has held teiecon conferences with many other licensees and.met with some valve manufacturers.
During these discussions, the NRC staff has stressed that positive actions must be taken as noted above
- to a?sure that containment integrity.would be maintained in the event of a DBA-LOCA.
As a result of these actions, we have learned from several licensees that at least*three valve vendors have. reported that their valves may not close against the ascentting differential pressure and the resulting dynamic loading of the design basis LOCA.
All identified.licensees who are affected have proposed to maintain the.*~alves in the closed position or to restrict the angular opening of the valves whenever primary containment integrity is required pending a re-evaluation which shows satisfactory valve perfonnance under the DBA-LOCA condition can be provided.
Recently, a report under 10 CFR Part 21 was received by the NRC from the manufacturer of butterfly valves which are installed in the primary containment at the Three Mile Island Unit 2 Nuclear Station. These butterfly valves are used for purge and exhaust purposes and are required to operate during accident conditions.
The report discusses the use of an unqualified solenoid valve for a safety-related valve function which requires operation under accident conditions.
The solenoid valve is used to pilot control the pneumatic valve actuators which are installed on the containment ventilation butterfly valves at this facility.
Your re-evaluation of valve performance for conditions noted in the previous paragraph must consider the concerns identified in IE*
Bulletin 79-0lA.
As the NRC review progresses, licensees which might have electrical.override circuitry problems are being advised not to use the override and to take compensatory interim measures to minimize the problem.
In light of the information gained during our reviews of your submittals dated January 30, August 30, and October 5, 1979 and the infonnation cited above, we believe an interim commitment from you* is required at this time. This is the case, even though you may have proposed Technical Specification changes or other long or short-term measures, which we are reviewing.
For your use, we have provided as an attachment an interim NRC staff posi"tion.
In addition, our recently developed "Guidelines for Demonstration of Operability of Purge and Vent Valves" were provided by separate letter to licensees of each operating reactor. This letter in no way relaxes any existing licensing requirements for your facility.
- I Mr. F. October 30, 1979 Because of the potential adverse effects on the public health and safety which could result from the postulated DBA-LOCA while operating with open purge or vent. valves, webeHeve your prompt response to this letter is required. In accordance with 10 CFR 50.54f, you are requested to inform us in writing within 45 days of receipt of this letter of your corrmitment to operate in confonnance with the enclosed interim position and to*provide us with *infonnation which demonstrates that you have initiated the purge and vent* valve operability verification on an expedited basis. The infonnation provided in your response will enable us to detennine whether. or not your license to operate Salem Unit No. 1 should be modified, suspended, or revoked.
Enclosure:
Interim Position for Containment Purge and Vent Valve Operation cc w/enclosure:
See next page Sincerely,
(), _z:lt14)(!<L&t-A. Schwencer, Chief Operating Reactors B.ranch #1 Division of Operating Reactors
- .-... ~...,.... -**.. *~-.~---
. /'
Mr. F. P. Librizzi Public Service Electric and Gas Company cc:
Mark J. Wetterhahn, Esquire Conner, Moore and Corber Suite 1050 1747 Pennsylvania Avenue, NW Washington, D. c.
20006 Richard Fryling, Jr., Esquire Assistant General Solicitor Public Service Electric and Gas Company 80 Park Place Newark, New Jersey 07101 Gene Fisher, Bureau of Chief Bureau of Radiation Protection 380 Scotch Road Trenton, New Jersey 08628 Mr. Hank Midura, Manager Salem Nuclear Generating Station*
Public Service Electric and Gas Company 80 Park Place Newark; New Jersey 07101 Mr. R. L. Mittl, General Manager Licensing and Environment Public *Service Electric and Gas Company 80 Park Place Newark, New Jersey 07101 Salem Free Library 112 West Broadway Salem, New Jer.sey 08079 Leif J. Norrholm U *. S. Nuclear Regulatory Commi ssiQn Drawer I Hancocks Bridge, New Jersey 08038 October 30, l 979
INTERIM POSITION FOR.CONTAINMENT.PURGE AND VENT VALVE OPERATION PENDING.RESOLUTION.OF.ISOLATION.VALVE OPERABILITY Once the conditions listed below are met, restrictions on use of the containment purge and vent system isolation valves will be revised based on our review of your responses to the November 1978 letter justifying your proposed opera-tional mode.
The revised restricti,'ons can be establi'shed.separately for each
- system.
- 1. Whenever the containment integrity is required, emphasis should be placed on operating the contafoment in a passive mode as much as possible and on limiting all purging and venting times to. as low as achievable.
To justify venting or purging, there must be an established need to improve working conditions to perform a safety related surveillance or safety related maintenance procedure.
(Examples of improved working conditions would include deinerting, reducing temperature*, humidity*, and airborne activity sufficiently to permit efficient perfonnance or to si:gnificantly reduce occupational radiation exposures), and
- 2. 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 this:
- a. All isolation valves greater than 3 11 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 Specificattons, design criteria or operattng procedures.
The operabiltty of butter-fly valves may, on an inter*im basts, be demonstrated by limiting the valve to be no more than 300 to soo open (900 betng 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 wi'll tend to close when the fluid dynamic forces are introduced, and
- b. Modifications, as necessary, have been made to segregate the contain-*
ment ventilation isolation signals to ensure that, as a minimum, at least one of the automattc safety injection actuation si*gnals is un-inhibited and operable to initiate valve closure when a*ny other isolation signals may be blocked, reset,. or overridden.
- Only where temperature and humidity controls are not in the present design.