ML19346A168

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Responds to Concerns Raised Re Special Low Power Tests Proposed in 810514 Ltr Stating Commitments to Satisfy TMI Task Action Item I.G.1.Test Simulating Loss of Ac Power Condition for Reactor Sys Will Be Conducted
ML19346A168
Person / Time
Site: Fermi DTE Energy icon.png
Issue date: 06/03/1981
From: Colbert W
DETROIT EDISON CO.
To: Kintner L
Office of Nuclear Reactor Regulation
References
TASK-1.G.1, TASK-TM EF2-53430, NUDOCS 8106050307
Download: ML19346A168 (3)


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\ June 3, 1981 bf mg , EF2-53430 Mr. L.L. Kintner Division of Project Management Office of Nuclear Regulation U.S. Nuclear Regulatory Commission Washington, D.C. 20555

Dear Mr. Kintner:

Reference:

1. Enrico Fermi Atomic Power Plant , Unit 2, NRC Docket No. 50-341
2. R.L. Tedesco letter to Dr. W.H. Jens dated January 18, 1981
3. H. Tauber letter R.L. Tedesco (EF2-53285);

dated May 14, 1981 Subj ect: Simulated Loss of AC Power Special Test The following is submitted in response to the concerns raised regarding the special low power tests proposed in our previous letter (Reference 3) stating our commitments te satisfy TMI Task Action Item I.G.I.

With this letter Detroit Edison commits to conducting a test which simulates a loss of AC Power condition for the reactor and containment systems. The purpose of this test will be to obtain data relative to the performance of these systems under the imposed condition of no AC power avail-l able for mitigation of transient effects. This test is, however, conditioned on the results of a detailed safety evaluation concurred in by Detroit Edison and General Electric and accepted by the NRC under the requirements of 10 CFR 50.59.

During this test key ac powered systems or components will be secured or placed in OFF (as appropriate) to prevent .

them from affecting plant response during the transient.

, These will include, as a minimum:

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1. Feedwater-2.- RHR (all: modes)

, 3.' Core Spray

4. Drywell' Cooling
5. Penetration Cooling *i
6. MSIV's
7. Reactor Recirculation -
8. HPCI and RCIC Room Coolers
9. . Instrument Air Supply to. Containment Isolating the above systems will allow only the DC powered systems to aff ect the reactor r.nd containment- response, except for the~ CRD system. Continued operation of the CRD system during this test L(In-cluding the equipment and instruments' needed to support this system)'

' is necessary to prevent damage or degradation of the Control Rod Seals and Recirculation Pump seals. The relatively small amount:of water =

inj ected by the CRD pumps is not. considered to be enough. to -

significantly influence the test results.-

1 Test tarmination criteria will be established for parameters such <

as containment leakage, reactor water _ level, suppression pool temperature, drywell temperature, containment. pressure, HPCI and RCIC room temperatures, and-CRD temperatures. The test.will

also be terminated in the event that RCIC trips and cannot be re-i started within a certain time period of 'if any Safety / Relief valve sticks' open.

The tesc will be conducted at a convenient point- during the first fuel cycle, with the constraint that ' adequate decay heat ' exists to provide a valid test. Several options are being explored for test initiation (e.g. turbine trip from 5% power following load reduction, turbine trip from 85% power,' etc.) It is our position that the method finally selected will have little bearing on the test, since plant performance during the initial state of such a transient is j adequately tested in startup . test.

The following key factors should.also be emphasized regarding the performance of this test:

a. No blocking of low pressure ECCS functions will be provided.

Transient conditions imposed by the test are not expect ed to initiata these systems on low water level. Adequace data will be obtained prior to injection of low pressure ECCS flow on a high drywell pressure signal ir conjuction with a confirmatory low reactor pressure signal. If = initiation points are reached earlier in the test, this would represent a criteria for test f

termination and the ECCS would be ' allowed to function as designed.

l l b. In most if not all cases, Limiting Conditions. for Operation will l ,

not be violated. It is possible that as test plans are developed, certain LCO's will be identified as inhibiting test performance.

However, for LCO's that are being approached as a result of transient eff ects during the test, this will represent criteria for test termination to insure plant saf ety.

I c. Loss of power to plant instrumentation will not be sinulated.

To accomplish the major goal of this test, instrumentation will be maintained functional for proper data collection.

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This constraint is also considered necessary to insure plant safety.

d. ' Plant . AC busses will remain energized, -the emergency diesel' generators will be available or operating, and breakers to safeguards. equipment will not be racked out. These precautions are considered necessary for plant safety.

1 The commitments previously made on our response to Item I.G.I.

.(Reference 3) regarding the augmented operator training- through

. participation in the preoperational and startup test programs will -

be fullfilled. It is our intent however to replace the special tests described in Appendix A with the test described above.

We will provide the NRC with our detailed test procedure and the results of our Safety evaluation at least 30 days. prior to

performance of the test.

The results of t.his test and any other meaningful technical infor--

, mation which may be gained from the safety. analysis or procedure preparation will be incorporated into our operator training programs and plant specific simulator program as may be necessary.

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W.F.Colbert ~

Technical Director Fermi- 2 Proj ect WFC/sim cc: B. Little l-l l

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