ML17252A480

Letter Requesting an Amendment to the Facility Operating Licenses -Dresden Station Units 2 and 3. Purpose of This Change Is to Incorporate Technical Specifications Concerning Surveillance of Snubbers and Primary Coolant and Safeguard System

ML17252A480
Person / Time
Site:	Dresden   (DPR-019, DPR-025)
Issue date:	12/10/1974
From:	Brian Lee Commonwealth Edison Co
To:	Case E US Atomic Energy Commission (AEC)
References
Download: ML17252A480 (4)

Text

Commonwe-Edison e

Orie First National Plaza, Chicago, Illinois Address Reply to: Post Office Box 767 Chicago, Illinois 60690 Mr. Edson G. case Acting Director Directorate of Licensing Off ice of Regulation U.S. Atomic Energy Commission Washington, D.c.

20545

Subject:

Dresden Station units 2 and 3 Proposed Amendment to Facility Operating Licenses DPR-19 and DPR-25, AEC Dkts 50-237 and(SJ_0 ___ 2_4_"9)

Dear Mr. case:

Pursuant to 10CFRSO Part 50.59, commonwealth Edison company requests an amendment to facility operating licenses DPR-19 and DPR-25.

The purpose of this change is to incor-porate Technical Specifications concerning surveillance of snubbers and primary coolant and safeguard system piping.

The proposed amendment is indicated O!l at,tached revised Technical Specification pages.9la, 9lb and 99a.

The proposed amendment has received Onsite and Off-site review and has been approved as involving no unreviewed safety considerations.

The basis for this decision was the Technical Specification Bases ind.icated on attached revised page 99a.

One signed original and 59 copies are submitted for your approval.

SUBSCRIBED and SWORN to befo;re _me t.h~f ~*day of. Al C.t ~- 1r1J'.N. LJ 1974.

At.t.

very truly yours, J

D

~j/\\ t.'Y\\ du_"--(},

ByrJn Lee, Jr'. Q.

Vice-President 12651*

l.6 LIMITING CONDITION FOR OPERATION H.

Recirculation Pump Flow Mismatch

1.

Whenever both recirculation pumps are in operation, pump speeds shall be maintained within 100fe of each other when power level is greater than 80% and within 15% of each other-when power level is less than 80%.

2.

If specification 3.6.H.l cannot be met, one recirculation pump shall be tripped.

3.

Whenever one pump is operable and the remaining pump is in the tripped position, the operable pump shall be at a speed less than 65% before starting the inoperable pump.

I.

Snubbers On Primary Coolant and Safeguard System Piping

1.

Fram and after the date that a snubber is* determined to be inoperable, continued reactor operation is permissible only during the succeeding 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> unless the snubber is sooner made*

operable.

4.6 SURVEILLANCE REQUIREMENT

3.

The baseline data required to evaluate the conditions in Specifications 4.6.G.l and 4.6.G.2 will be acquired each operating cycle.

1:1~

Recirculation Pump Flow Mismatch Recirculation pumps speed shall be checked daily for mismatch.

I.

Snubbers On Primary Coolant and Safeguard System Piping At least every 120 days the following inspections shall be performed on snubbers.

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9la

3.6 LIMITING CONDITION FOR OPERATION

2.

If this condition cannot be met, an orderly shutdown shall be initiated and the reactor shall be in a cold Shutdown condition within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

4.6 SURVEILLANCE REQUIREMENT

1.

The fluid level of snubbers shall be determined and recorded.

Snubbers showing significant fluid loss shall be repaired and the seals inspected.

The mechanical connec-tions of all snubbers shall be inspected.

~

At least once each refueling outage, the ~

following inspections shall be performed:

1.

At least one snubber shall be disassembled and its seals examined to determine if there has been any damage or abnormal degradation.

9lb

3.6 LIMITING CONDITION FOR OPERATION H.

Jet Pump Flow Mismatch The LPCI loop selection logic has been described in the Dresden Nuclear Power station Units 2 and 3 FSAR, Amendments 7 and 8.

For sane limited low proba-bility accidents with the recirculation loop operating with large speed dif-ferences, it is possible for the logic to select the wrong loop for injection.

For these limited conditions, the core spray itself is adequate to prevent fuel temperatures from exceeding allow-able limits.

However, to limit the probability even further, a procedural limitation has been placed on the allowable variation in speed between the recirculation pumps.

The licensee's analyses indicate that above 80% power the loop select logic could not be expected to function at a speed differential of 15%.

Below 80%

power the loop select logic would not be expected to function at a speed differential of 20%.

This soecif ication provides a margin of 5% in p\\imp speed differential before.a problem could arise. If the reactor is operatin9 on one pump, the loop select logic trips that Pl;llllP before making the loop selection.

In addition, during the startup of Dresden

~

it 2, it was found that a flow mismatch twee~ the two ~ets ot 1et PUmPS caused y a difference in recireula~1on loops could set up a vibration until a mismatch in speeQ of 27% occurred.

The 10"~ and 15%

speea mismatch restrictions provide addi-tional ma~g!n before a pump vibration problem wiil occur.

/1 4.6 SURVEILLANCE REQUIREMENTS I.

Snubbers On Primary Coolant and Safeguard System Piping

f. *-

Snubbers are designed to prevent unre-strained vibration of piping during some postulate dynamic loading condition such as earthquakes.

Loss of fluid due to a seal failure could result in a snubber ~

failing to perform its design function

• and result in exceeding the piping design stress.

Therefore, i~ is required that all snubbers on primary coolant and safeguard system piping be operable for continued plant operation.

The selection of the inspection interval for ethylene-propylene is based on both laboratory testing and in-plant service.

The laboratory testing consisted of both.long term aging and accident simu-lation testing.

Snubbers with ethylene-propylene seals have been in reactor

~

service for over one year, and surveillanc'19' every 120 days has confirmed satisfactory performance.

The 120 day surveillance

• interval will be maintained until further in-plant experience is available to justify longer inter-Vals.

The satis-factory testing and one year inservice performance of the snubbers equipped with ethylene-propylene seals justifies the interim surveillance interval.

99a