ML17331A512
| ML17331A512 | |
| Person / Time | |
|---|---|
| Site: | Cook  |
| Issue date: | 10/06/1980 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML17331A511 | List: |
| References | |
| NUDOCS 8011060232 | |
| Download: ML17331A512 (17) | |
Text
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~O UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 42 TO FACILITY OPERATING LICENSE NO.
DPR-58 AND AMENDMENT NO.
24 TO FACILITY OPERATING LICENSE NO.
DPR-74 INDIANA AND MICHIGAN ELECTRIC COMPANY
,DONALD C.
COOK NUCLEAR PLANT UNIT NOS.
1 AND 2 DOCKET NOS. 50-315 AND 50-316
- ntroduction and Back round
.he Three.'iile Esland Unit 2 (TMI-2) accident and subsequent investigations and studies highlighted the importance of'he Auxiliary Feedwater (AFM) System n
.he mitigation of transients and accidents.
As part of our assessment of the TMI-2 accident and related implications or operating plants, we evaluated the AFM systems for all operating and near-term operating license plants naving nuclear steam supply systems (NSSS) designed by Mestinghouse (NUREri-0611) or Combustion Engineering (tlUREG-0635).
Our evaluations of these system designs are contained in the NUREGs along wi th our recommendations for each plant and the concerns which led to each recommendation.
The objectives of the evalua-
.ion wer
".o:
(1) identify necessary changes in APA svstem design or related procedures in order to assure the safe operation of these plants, and (2) to dentify other system characteristics of the APA system which. on a long term
- basis, may require system modifications.
To accomplish these objectives, we:
(I)
Reviewed plan. specific AFvl system designs in light of current regulatory requirements (SRP)
- and, 80 110604%-
(2)
Assessed the relative reliability of the various AFW sys.ems under various loss of feedwater transients (one of which was the initiating event of'MI-2) and othei postulated
<ailure conditions by determining the potential for API system failure due to comnon causes, single point vulnerabilities, and human error.
We concluded that the implementation of the recommendations identified during this review will considerably improve the reliability of the AFW systems for each operating plant.
The following generic recommendations did not apply to this plant:
GS-l, GS-3, GS-8, GL-1 and GL-2.
The basis for these recommendations can be found in Appendix III of NUREG-0611, and the system description which deter-mined the basis for not applying these recommendations can be found in Appendix X of NUREG-0611.
II.
Im lementation of Our Recommendations A.
Short Term Recommendations 1.
Recommendation GS "The licensee should lock open single valves or multiple valves in series in the AFW system pump suction piping and lock open other single valves or multiple valves in series that could d
2 interrupt all AFW flow.
Monthly inspections should be performed to 1
verify that these valves are locked and in the open position.
These inspections should be proposed for incorporation into the surveillance requirements of the plant Technical Specifications.
See Recommendation GL-2 for the longer-'term resolution of this concern,"
I'n response to this recommendation, the licensee indicated in a letter dated Oecember 11, 1979 (AEP:NRC:00300), that each valve, not automatic or power-operated, in the auxiliary feedwater flow path is locked or I
sealed in its correct position.
The licensee, also stated, present Technical Specifications Surveillance Item 4.7.1.2 requipes monthly verification of unlocked valves in the auxiliary feedwater flow path and present procedures require monthly verification of locked or secured valves.
The licensee's present Technical Specification 6.8.l.c require implementation of these procedures.
In response to our request, the licensee proposed a change to Technical Specifications to include the locked or secured valves in the auxiliary feedwater flow Path.
We have reviewed the licensee's response and proposed Technical Specifications and conclude that Recommendation GS-2 is adequately met and, therefore, the licensee's response to GS-2 and proposed Tech-nical Specifications are acceptable.
t 2.
Recommendation GS-4
-. "Emergency procedures for transfer ing to alter-I nate sources of AFW supply should be available to the plant operators, These procedures should include criteria to inform the operators
- when, I
and in what order, the transfer to alternate water sources shoul'd take place.
The following cases should be covered by the procedures:
- The case in which the primary water supply is not initially available.
The procedures for this case should include any operator actions required to protect the AFQ system pumps against self-damage before water flow is initiated; and,
- The case in which the primary water. supply is being depleted.
The procedure for this case should provide for transfer to the alternate water sources prior to draining of the primary water supply."
In response to this recommendation, the licensee indicated in a letter dated March 28, 1980 (AEP:NRC:00307A), that Procedure No. OHP-4022.055.003 entitled "Loss of Condensate to Auxiliary Feedwater Pumps" had been developed to fulfill th-is recommendation.
,This procedure prov des
".ho operator with instructions to switch the auxiliary feedwater pumps suction from the condensate storage tank to the alternate Essential Service Water Supply (ESW).
On a lo-lo level alarm for the condensate storage
- tank, an operator is sent to the auxiliary feedwater pump rooms to align the essential ser vi~e wite~ valves to nr ovid~ suction tn earth o< th~ pumps By npenin~
the manual valve and the motor-operated valv~ in ~eries
~n e~ch ~lt~rn~te ~upnly ~in~, both motor-driven auxiliary feedwater pumps and the turbine - driven auxiliary feedwater pump will be supplied by the ESW.
We conclude that recommenda-tion GS-4 is adequately
- met, and therefore, acceptable pending verifi-cation of the procedure by the Office of Inspection and Enforcement.
3.
Recommendation GS "The as-built plant should be capable of providing the required AFW flow for at least two hours from one AFW pump train independent of any alternating current power source.
If manual AFW system initiation or flow control is required following a complete loss of alternating current power, emergency procedures should be established
for manually initiating and controlling the system under these conditions.
Since the water for cooling of the lube oil for the turbine-driven pump bearings may be dependent on alternating current power, design or procedural changes shall be made to eliminate this dependency as soon as practicable.
Until this is done, the emergency procedures should provide for an individual to be stationed at the turbine-driven pump in the event of the loss of all alternating current power to monitor pump bearing and/or lube oil temperatures.
If necessary,- this operator would operate the turbine-driven pump in an on-off mode until alternating current power is restored.
Adequate lighting powered by direct current power sources and communications at local stations should also be pro-
.vided if manual initiation and control of the AFW system is needed.
(See Re'commendation GL-3 for the long-term resolution of this concern.)"
l In response to this recommendation, the licensee indicated in a letter dated December ll, 1979, that until modifications to meet recom-I4 mendation GL-3 are complete, emergency procedures will provide for manual initiation and control of the auxiliary feedwater system in case of a complete loss of AC power.
The turbine-driven auxiliary feedwater pump areas have been 'provided with emergency lighting and emergency radio cooeunications,"
both powered by direct current sources.
The existing turbine-driven auxiliary feedwater pump bearing cooling system is independent of both AC and DC power.
Me conclude that recoomendation GS-5 is adequately
- met, and therefore, acceptable pending verification of the procedure by the Office of Insp ction and Er fnrcement.
I 4.
Recommendation GS "The 1icensee should confirm flow path availability of an AFM system flow train that has been out of service to perform periodic testing or maintenance as follows:
Procedure should be implemented to require an operator to determine that, the AFW system valves are properly aligned and a second operator to independently verify that the valves are properly aligned.
- The licensee should propose Technical Specifications to assure that prior to plant startup following an extended cold shut-
- down, a flow test would be performed to verify the normal flow path from the primary AFM system water source to the steam generators.
The flow test should be conducted with AFM system valves in their normal alignment."
In response to this recommendation, the licensee in a letter dated
.lay 23, 1980, indicated that the plant procedures would be changed to include back-up verification by a second operator to existing procedures which require verification of valve alignment after testing and maintenance, In a letter dated December ll, 1979, the licensee indicated that, "the operating procedure for uni t heatup from cold shutdown to hot standby calls for operation of both the motor driven auxiliary feed pumps and the turbine driven auxiliary feedpump.
The pumps take suction from their primary water source and -deliver flow
to the steam generators in order to control steam generator water levels."
We concluded that a Technical Specification to require a
flow test is not required, in that both motor driven pumps and the turbine driven pumps are used to deliver flow to the steam generator s
during unit startup.
Me conclude that recommendation GS-6 is adequately
- met, and therefore, acceptable, pending verification of operating arid surveillance procedures by the Office of Inspection and Knforceme<<t.
5.
Recommendation GS-7 -"The licensee should verify that the automatic start AFM signals and associated ci rcuitry are safety grade.
If this cannot be verified, the AFM system automatic initiation system should be modified in the short-term to meet the functional requirements listed below.
For the longer term, the automatic initiation signals and circuits should be upgraded to meet safety grade requirements as indicated in Recommendation GL-5.
- The design should provide for the automatic initiation of the auxiliary feedwater system flow.
- The automatic initiation signals and ci rcuits should be designed so that a single failure will not result in the loss of auxiliary feedwater system function,
- Testabi lity of the initiation signals and circuits shall be a
feature of the design.
- The initiation signals and circuits should be powered from the emergency buses.
- Manual capability to initiate the auxiliary feedwater system from the control room should be retained and should be imple-mented so that a single failure in the manual circuits will not result in the loss of system function.
- The alternatin'g current motor-driven pumps and valves in the auxiliary feedwater system should be included in the auto-matic actuation (simultaneous and/or sequential) of the loads to the emergency buses.
- The automatic initiation signals and circuits shall be designed so that their failure will not result in the loss of manual capability to initiate the AFW system from the control room."
In response to this recommendation, the licensee. indicated in a letter dated December 11, 1979, that the present AFW system automatic initiation signals an'd control systems are safety grade.
The licensee's lt response to Recommendation GS-7 is acceptable.
The long term counter-part of this recommendation, GL-5 (Safety Grade Automatic Initiation) is still under review.
Additional clarification of our requirements.
for this item is inc'luded in our September 5, 1980 letter on Prelimi-nary Clarification of TMI Action Plan Requirements.
B.
Additional Short Term Recommendations 1.
Recommendation
- "The licensee should provide, redundant level indica-tions and a low level alarm in the control, room for the
'AFW system primary water supply'o allow the operator to anticipate the need to
make up water or transfer to an alternate water supply and prevent low pump suction pressure condition from occurring.
The low'level alarm setpoint should allow at least 20 minutes for operator action, assuming that the largest capacity AFM pump is operating."
In response to this recommendation, the licensee stated that the existing Condensate Storage Tank (primary water source) is orovided with redundant level sensors which provide signals for a continuous recorder.
Low and low-low alarms which are powered by the, same OC power bus, are provided for each level indicator sensor.
The low-low level alarm is set to allow 35 minutes for operator. action.
In our posi tion letter of April 4, 1980, to the licensee we stated that this design was acceptable for the short term.
For the long
- term, we require the licensee to meet the following:
- 1) Provide a
redundant level indicator in addition to the existing redundant level alarms inside the control room.
The current design with a single level recorder does not meet the single failure criterion; 2)
Power supplies for the level indi cation and alarms should be redundant.
The II present design utilitizes a single DC power source. 'ince the con-densate storage tank is not classified seismic Category I, use of non-Class IE circuitry and power supplies are acceptable provided one power train has a back-up battery source; and 3) reset the low-I low level alarm to allow at least 20 minutes for operator's
- action, assuming that the largest capacity AFW pump is operating.
The licensee's response to items 1
and 2 of our position is not acceptable.
The licensee is required to make modifications to 'provide redundancy as stated, in our Apri,l 4, 1980 letter'.
F 2.
Recommendation This recommendation has been revised from the ori inal 1
recommendation in NUREG-0611
- "The licensee should perform a 48-hour endurance test on all<AFW system pumps, if such a test or continuous period of operation has not been accomplished to date.
Following the 48-hour pump run, the pumps should be shut down and cooled down and then restarted and run for one hour.
Test acceptance criteria should include demonstrating that the pumps remain within design limits with respect to bearing/bearing oil temperatures and vibration and that pump room ambient conditions (temperature, humidity} do not exceed environ-mental qualification;,limits for safety related equipment in the room."
In response to this recommendation, the licensee in a letter dated June 26, 1980, indicated that it will perform the 48-hour endurance test on all auxiliary feedwater pumps for both units by December 31, 1980
~
The licensee further indicated the results of the test will be provided within 60 days after all tests are completed.
Based on the above licensee's commitment, we conclude that the response to this recommendation is acceptable.
- However, we intend to evaluate the,AFM pump test results to confirm that the AFW pumps are acceptable.
if the test results are not acceptable, we will then require modifica-tion and provide a safety evaluation regarding the test and modifica-tions.
3.
Recommendation
- "The licensee should implement the following require-ments which are identi ca 1 to Itern 2.1.7.b of NUREG-0578:
Safety-grade indication of AFW flow to each steam generator should be provided in the control room.
The auxiliary feed-water flow instrument channels should be powered from the emergency power diversity requirements for the auxiliary feed-water system set forth in Auxiliary Systems Branch Technical Position 10-1 of the Standard Review Plan, Section 10.4.9."
Our Lessons Learned Implementation Task Force has completed its review of the short term requirements and their evaluation was forwarded to the licensee in a letter dated March 20, 1980.
The long term require-ments for this recommendation are still under review.
Additional clarification of our requirements for this item is included in our September 5, 1980 letter on Preliminary Clarification of TMI Action Plan Requirements.
4.
Recommendation
- "Licensees with plants which require local manual realignment of valves to conduct periodic tests on one AFW system
- train, and there is only one remaining AFW train available for operation, should propose Technical Specifications to provide that a dedicated individual who is in'communication with the control room be stationed at the manual valves.
Upon instruction from the control room, this operator would realign the valves in the AFW system train from the test mode to its operational alignment.
The licensee, in its letter of December 11, 1979, stated that this recommendation does not apply to D.
C.
Cook 152.
The auxiliary feedwater system included a turbine-driven feedwater pump and two motor-driven feedwater pumps shared by both units.
Each motor-driven auxiliary pump was connected to two steam generators in each unit; thus, each unit's four steam generators were supplied by both motor-driven pumps.
However, the licensee recently modified the AFW system to provide three AFW pumps per unit, one turbine-driven pump and two motor-driven pumps.
Further, the Technical Specifications only allow testing of one pump at a time.
We conclude that this recommendation does not apply to D. C.
Cook, 182.
C.
Lon Term Recommendations 1.
Recommendation GL By letter dated August 9, 1979, the licensee proposed making modifications and Technical Speci-fication changes to the AFW System to make the turbine driven train independent of AC power sources
The following recommendation should be met when these modifications are P
1 complete.
At least one AFM system pump and its associated flow path and essential instrumentation should automatically initiate AFW system flow and be capable of being operated independently of any alternating current power source for at least two hours.
Conversion of direct current power to alternating current is acceptable,"
In response to this recommendation, the licensee indicated a letter dated December ll, 1979, that "The turbine driven auxiliary feed-water pump is being modified to eliminate its dependence on AC power for automatic initiation of 'flow and operation."
The staff SER supporting Amendment 35 to Facility Operating License dated December 20, 1979 addresses this issue.
It was concluded in that amendment that I
the licensee's response is acceptable.
2.
Recommendation GL "Licensees having plants with unprotected normal AFW system water supplies should evaluate the design of their AFW 1
systems to determine if automatic protection of the pumps is necessary following a seismic event or a tornado.
The time available before pump damage, the alarr)s and indications available to the control room
- operator, and the time necessary for assessing the problem and taking action should be considered in determining whether operator action can be relied upon to prevent pump damage.
Consideration should be given to f
providing pump protection by means such as automatic switchover of the pump suctions to the alternate safety-grade source of water, automatic pump trips on low suction pressure or upgrading the normal source of water to meet Seismi'c Category I and tornado protection requirements."
I:n response to this recommendation, the licensee by a letter dated December 11, 1979, indicated that an automatic AFM pump trip on low suction pressur e will be installed.
The pump trip will.be provided with an alarm in the control.room and operators will be instructed to follow emergency procedures for transferring to alternate source of AFM supply.
We conclude the licensee's response meets our recommenda-tion and, therefore,:is acceptable.
t 3.
Recommendation GL "The licensee should upgrade the AFW system automatic initiation signals and circuits to meet safety-grade require-ments."
In response to this recommendation, the licensee indicated in a letter dated December 11, 1979, that the present AFM system automatic initia-tion signals and circuits are safety grade.
The licensee's design is under review.
Additional clarification of our require-ments for this item is included in our September 5, 1980 letter on Preliminary Clarification of TMI Action Plan Requirements.
Environmental Consideration We have determined that thy amendments do not authorize a change in effluent types or total amounts nor an i ncrease in power level and will not result in any significant environmental impact.
Having made this determination, we have further concluded that the amendments involve an action which is insignificant from the standpoint of environmental impact and, pursuant to 10 CFR $51.5(d)(4), that an It environmental impact stateinent or negative declaration and environ-mental impact appraisal need not be prepared in connection with the I
issuance of these amendmerjts.
Conclusion We have concluded, based on the considerations discussed above, that:
(1) because'he amendments
'do not involve a significant increase in the probabi lity or consequences of accidents previously considered and do not involve a significant decrease in a safety margin, the amendments do not involve a significant hazards consideration, (2) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed
- manner, and (3) such activities will be conducted in compliance with the Commission's regulations and the issuance of these amendments will not be inimical to the common defense and security or to the health and safety of the public.
Date:
October 6, 19SO