ML19260B195
| ML19260B195 | |
| Person / Time | |
|---|---|
| Site: | Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png |
| Issue date: | 12/04/1979 |
| From: | Counsil W CONNECTICUT YANKEE ATOMIC POWER CO. |
| To: | Eisenhut D Office of Nuclear Reactor Regulation |
| References | |
| TASK-10, TASK-RR NUDOCS 7912070400 | |
| Download: ML19260B195 (6) | |
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CONNECTICUT YANKEE AT O M IC POWER COMPANY BERLIN. CO N N ECT!C U T P.O. BOX 270 H ARTFORD, CONN ECTICUT 06101 TsLapwo=s 203-666-6911 December 4, 1979 Docket No. 50-213 Darrell G. Eisenhut, Acting Director Division of Operating Reactors Office of Nt., ' ear Reactor Regulation U. S. Nuclear Regulatory Commission Washington, D. C.
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References:
(1)
D. G. Eisenhut letter to D. C. Switzer dated October 11, 1979.
(2)
W. G. Counsil letter to D. L. Ziemann dated June 1, 1979.
(3)
W. G. Counsil letter to D. G. Eisenhut dated October 18, 1979.
(4)
W. G. Counsil letter to H. R. Denton dated November 21, 1979.
(5)
W. G. CounFil letter to J. Hendrie dated November 30, 1979.
(6)
D. L. Ziemann letter to W. G. Counsil dated June 7, 1979.
(7)
D. C. Switzer letter to K. R. Goller dated February 5,1975.
Gentlemen:
Haddam Neck Plant NRC Requirements for Auxiliary Feedwater Systems In Reference (1), Connecticut Yankee Atomic Power Company (CYAPCO) was requested to review the Haddam Neck Plant against the applicable requirements of Enclosure (1) of Reference (1) to determine the current degree of conformance.
The results of this evaluation and a schedule and commitment for implementation of changes was also requested.
In addition, CYAPCO was requested to respond to a generic request for additional information regarding auxiliary feedwater systems, provided as Enclosure (2) of Reference (1).
In response to those requests, the following information is provided.
It is first noted that the modification to the AFW system to eliminate the need for service water for the AFW turbine-driven pump lube oil coolers has been completed.
Thus, AC dependence for cooling of the steam-driven pumps has been eliminated.
The recommendations of Enclosure (1) are addressed below, in accordance with the numbering system given in Reference (1).
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Short-Term (1) Recommendation GS-1 The NRC request for proposed modifications to Technical Specifications was provided in Reference (2).
(2) Recommendation GS-2 The inspection of all suction valves is done monthly in conjunction with the pump surveillance test.
The positions of these valves are verified before and af ter each test.
The in-service inspection Technical Specifications include requirements for the surveillance and verification of these and other safety-related valves.
No further action is required.
(3) Recommendation GS-4 The primary water supply for the auxiliary feedwater pump at the Haddam Neck Plant is the demineralized storage tank with the alternate water supply being the primary water storage tank.
Demineralized water storage tank level is monitored to ensure that water is available for the auxiliary feedwater pump. Technical Specifications require that there be 50,000 gallons of primary water and 80,000 gallons of alternate water. The demineralized water tank is equipped with level indicator and is alarmed.
Procedures for transferring the auxiliary feedwater pump water supply from the primary water supply to the alternate water supply are scheduled for completion by January 1, 1980.
(4) Recommendation GS-5 The auxiliary feedwater system at the Haddam Neck Plant is independent of the electrical system and loss of alternating current power will not affect operation of this system.
In addition, an emergency procedure for manually operating the auxiliary feedwater system can be implemented if required.
Adequate portable lighting and communication are available in the control rcom for the prescribed manual actions.
(5) Recommendation GS-6 CYAPCO presantly maintains procedures at the Haddam Neck Plant which require that different operators verify proper valve alignments in each redundant flow path of the auxiliary feedwater system.
In other words, one operator performs the flow path verification for Train A and a dif ferent operator performs the flow cath verification for Train B.
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, This level of independence is consistent with the requirements on other safety systems, and has been demonstrated to be adequate to ensure that safety-related systems are operable when required.
Technical Specifications require that, at refueling intervals, the capability of each pump to attain rated flow at 450 gpm be demonstrated.
However, this flow is not discharged into the steam generator during testing.
During start-up, however, when the steam generator is in its wet lay-up position, and as steau becomes available, the auxiliary feedwater pumps are utilized to maintain water level.
In this condition, the auxiliary feedwater system valves are in their normal alignment and, thus, discharging into the steam generator. By maintaining proper water level in the steam generators, flow path availability is assured.
CYAPC0 has determined that existing or proposed procedures, Technical Specificctions, and inservice inspections adequately assure auxiliary feedwater flow path availability, and fulfill the intent of this recommenda-tion.
(6) Recommendation GS-8 CYAPCO continues to believe that this recommendation is inappropriate as documented in References (3) and (4). A detailed response was provided in Reference (5).
(7) Recommendation X.5.3.1. (7)
The Haddam Neck Plant Surveillance Procedure No. 5.1-13, monthly operational check of the auxiliary feedwater pump, has been revised to require that all valves in the normal auxiliary feedwater flow path remain open during the rest.
Precedure No. 5.1-14, annual fica capacity test of the auxiliary feed-water pump, will be revised to prevent testing at power. The procedure is scheduled to be revised by July 1,1980 or prior to performing the next test.
Additional Short-Term Recommendations (1) The currently installed level instrumentation on the demineralized water storage tank consists of a low level alarm in the control room. A redundant level alarm, such that both will provide the requested 20 minutes for operator action, will be installed by Jan'iary 1, 1981.
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(2) The significant financial impac: associated with this recommendation far exceeds the benefits with respect to reliability verification, in that the auxiliary feedwater pumps have been operated reliably for extended periods at hot standby as a result of normal plant evolutions.
CYAPCO is presently reviewing the operating history of the Haddam Neck Plant auxiliary feedwater system and will address the appropriate-ness of supplemental endurance tests subsequent to this review scheduled for completion on or about January 1, 1980.
(3) CYAPCO's response to this recommendation is documented in References (3) and (4).
(4) This recommendation is not applicable, as local manual realignment of valves is not required for periodic testing of the auxiliary feedwater system.
Additional Long-Term Recommendations (1) A passive failure of the common pump suction line or the non-essential condensate service line to which the auxiliary feedwater system (AFS) suction line is attached would prevent the AFW system from supplying feedwater to the steam generators even without an active failure.
The low probability of an undetected passive failure in these low pressure service lines does not warrant the installation of additional redundant parallel flow paths.
These lines are also periodically tested under CYAPCO's inservice inspection program.
If the AFS were disabled by one of the above failures, the motor-drivea main feed pumps would be available, unless there is a concurrent loss of non-vital power.
If by a remote possibi] 4 ty, non-vital power was concurrently lost, CYAPCO has described a method for removing core decay heat by blowing down the RCS to the primary containment, via the pressurizer power operated relief valves, and injecting coolant with the safety injection system.
Long-term cooling could then be accomplished by either ECCS recirculation or by use of the RRR system (see References (6) and (7)).
In summary, CYAPCO's response is based on the low probability of a passive failure occurring in these lines, the possibility of using the motor-driven main feed pumps to restore feedwater, and availability of the safe shutdown systems if necessary.
(2) CYAPCO continues to believe that this recommendation is inappropriate as documented in References (3) and (4). A detailed response was pro-vided in Reference (5).
(3) Botb steam turbine auxiliary feedwater pumps discharge to a common crt ss-connect line which supplies water via two parallel paths to the main steam generator feedwater system. A passive failure in this line would elbainate 1512 042
all auxiliary feedwater flow to all steam generators.
Installation of an isolation vslve in this line would provide an operator a method of isolating a pipe break in the AFWS and allow the addition of auxiliary feedwater to the steam generators by at least one path, Therefore, the installation of a normally open air operated isolation valve in this crossconnect line will permit the necessary isolation.
Manual control of this valve would be provided in the control room.
The motor-driven feed pump which CYAPCO is presently in the process of installing does not meet Category I equipment requirements.
This pump will only be aligned temporarily using a pipe spool piece during startups to supply feedwater to the steam generators when the steam-driven auxiliary feedwater pumps are not available. Due to the low probability of a passive failure in this crossconnect line and the addition of the cross-connect isolation valve, the Laplementation of a qualified motor-driven auxiliary feedwater pump is not necessary.
If the AFW system should become disabled due to a single passive failure in the suction line or a passive failure to one of the pump discharges and an active failure to the other pump, the motor-driven feed pumps would be available, unless there is a concurrent loss of non-vital power.
Only with the above events concurrent with the loss of offsite power would CYAPCO be required to remove core decay heat by blowing down the RCS to the primary containment, via the pressurizer power operated relief valves, and injecting coolant with the safety injection systems. Long-term cooling ie then provided by ECCS or the RHR system, as described in References (6) and (7).
This is an acceptable means by which the plant can be brought to a safe shutdown condition.
In summary, the NRC recommendation to install an isolation valve in the common crossconnect line between the two auxiliary feedwater pumps is acceptable.
Pending NRC concurrence of CYAPCO's response and procurement of this valve, this valve would be installed during the 1981 cefueling outage.
The NRC recommendation to knplement the motor-driven feed pump presently being installed to Category I requirements and to maintain the capability of supplying AFW flow following a postulated pipe break anywhere in the AFW pump discharge lines plus a single active failure is unnecessary.
This is based on the addition of a crossconnect isolation valve, the possibility of using the motor-driven main feed pumps to restore feedwater, and the availability to use the safe shutdown systems if necessary.
CYAPCO acknowledges the existence of SEP topics addressing these concerns.
The relevance of this concern is emphasized in Reference (5).
With regard to Enclosure (2) of Reference (1), CYAPCO is committed to reapond to the information requests identified in the Enclosure.
Our current estimate for completion of this effort is May 15, 1980.
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We trust you find the above information responsive to your requests.
Very truly yours, CONNECTICUT YANKEE ATOMIC POWEP. COMPANY 1
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bN&
W. G. Counsil Vice President 1512 044