ML20245H699

Safety Evaluation Supporting Amends 34 & 35 to Licenses DPR-82 & DPR-80,respectively

ML20245H699
Person / Time
Site:	Diablo Canyon
Issue date:	04/14/1989
From:	Office of Nuclear Reactor Regulation
To:
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ML20245H697	List: ML20245H692 ML20245H699
References
NUDOCS 8905030485
Download: ML20245H699 (3)

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UNITED STATES

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. NUCLEAR REGULATORY COMMISSION

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' WASHINGTON, D. C. 20555 t

SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 35 TO FACILITY OPERATING LICENSE NO. DPR-80 I

AND AMENDMENT NO. 34 TO FACILITY OPERATING LICENSE NO. DPR-82 i

PACIFIC GAS AND ELECTRIC COMPANY DIABLO' CANYON NUCLEAR POWER PLANT, UNIT NOS. 1 AND 2 DOCKET N1. 50-275 AND 50-323 1

1.0 INTRODUCTION

I By letter dated March 13,1987,(ReferenceLAR87-03),PacificGasand Electric Com)any (PG&E or the licensee) requested amendments to the combined Tec1nical Specifications (TS) for the Diablo Canyon Nuclear Power. Plant, Unit Nos. 1 and 2.

The proposed amendments make the following changes to the TS:

A.

TS 4.7.5.1, " Control Room Ventilation System," is revised to require that once per month, for each of the two control room ventilation system (CRVS) trains, one of the two redundant sets of booster and pressurization supply fans must be tested for 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> with the heaters operating. The present TS requires both sets of q

fans in each CRVS train to be teste6 monthly. The revised TS also requires that once per month,' each main supply fan, booster fan,

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and pressurization fan must be tested for one kur to demonstrate i

1 fan operability. The present 15 requires only the main supply fans to be tested for 15 minutes.

B.

Table 3.?-1 of TS 3/4.3.1, " Reactor Trip System Instrumentation,"

is revised to clearly require a Quadrant Power Tilt Ratio determination to be made only if the plant is above 50 percent 1

power. The previous wording of the TS could have, under some circumstances, required plant shutdown in siteations when reduction to 50 percent power would be sufficient to maintain the de)arture j

from nucleate boiling (DNB) and linear heat generation wit 11n their 1

limits.

C.

Table 4.3-1 of TS 3/4.3.1 is revised to allow a plant heat balance

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to be performed, during startup, between 15 cad 30 percent power.

The previous TS could be interpreted to requir; the heat balance to be performed immediately upon reaching 15 percent power. This could result in a lest accurate heat balance, and would unnecessarily constrain plant operators during startup.

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' 2.0 DISCUSSION 1

The NRC staff has reviewed each of the three proposed changes and finds

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.them to be acceptable as follows:

A.

TS 4.7.5.1, " Control Room Ventilation System."

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The 10-hour test specified in TS 4.7.5.1.b.1 derives from the guidelines of Regulatory Guide 1.52, which states that each engineered safety teatures (ESF) atmosphere cleanup train should be operated at least 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> per month, with the heaters on, to reduce the buildup of moisture on the adsorbers and high-efficiency particulateair(HEPA) filters. Each CRVS train has two redundant booster fans, pressurization fans, and main supply fans.

However, each train has only one set of HEPA filters, charcoal adsorbers, and heaters. Thus, it is necessary to run only one booster fan, q

pressurization fan, and main sup)1y fan on each train for 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> with the heaters on to dry out t1e adsorbers and filters.

Therefore, changing this TS to allow the test to be conducted with either redundant set of fans, rather than both redundant sets of j

fans is acceptable, because the objective of the TS will still be l

met.

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The test specified in TS 4.7.5.1.b.2 derives from the requirement to verify the operability of all fans every 31 days.. The change l

requires all main supply fans, booster fans, and pressurization 1

supply fans to be tested. Yhe present.TS requires only the main supply fans to be tested.

In discussions with the licensee, it was agreed that testing the fans for one hour provided a higher degree of ussurance that the fans are operable than the previously specified 15 minute test. Because this change requires all fans to be tested for a longer period of time, it is more conservative than the present TS and therefore is acceptable to the staff.

B.

TS 3/4.3.1, Table 3.3-1, " Reactor Trip System Instrumentation,"

A ction Statement 2.c This TS is revised to clearly require a Quadrant Power Tilt Ratio (QPTR) determination to be made only if the plant is above 50 percent power. The previous wording of the TS could have, under some circumstances, required plant shutdown ir, situations when reduction to 50 percent power would be sufficient to maintain the departure from nucleate boiling (DNB) and linear heat generation within their limits. This change is acceptable to the staff because reducing power is an acceptable way of maintaining the i

plant within its DNB and linear heat generation rate limits.

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' Also, the frequency of once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> is deleted from this part of the TS because it is already required by TS 4.2.4.2.

i C.

TS 3/4.3.1, Table 4.3-1, " Reactor Trip System Instrumentation Surveillance Requirements," Note (2).

This change allows a plant heat balance to be performed, during startup, between 15 and 30 percent power. The previous TS could be interpreted to require the heat balance to be performed imediately upon reaching 15 percent power. This could result in a less accurate heat balance, and would unnecessarily constrain plant operators during startup. Because this change will not have an adverse effect on plant safety, the staff finds it to be accepttble.

For the reasons given above, the NRC staff finds the above changes to be acceptable.

3.0 ENVIRONMENTAL CONSIDERATION

These amendments involve changes in the installation or use of facility components located within the restricted area as defined in 10 CFR Part

20. We have determined that the amendments involve no significant increase in the amounts, and no significant change in the types, of any effluents 1-that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure. The Comission has previously issued a proposed finding that the amendments involve no significant hazards consideration and there has been ne public coment'on such finding. Accordingly these amendments meet the eligibilit criteria for categorical ex,clusion sat forth in 10 CFR 51.22(c)(y).

9 Pursuantto10CFR51.'22(b),noenvironmentalimpactstatementor environmental assessment need be prepared in connection with the issuance of these amendments.

4.0 CONCLUSION

We have concluded, based on the considerations discussed above that:

I (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation ir the proposed manner, and I

k ) such activities will be condui.ted in compliance with the Comission's regulations and (3) tiie issuance of the:e amendments will not be inimical to the comon defense and security or the health and safety of the public.

I Princippi Contributors:

H. Rood T. Quay J. Hayes Dates April 14, 1989

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