ML20086G670
| ML20086G670 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 07/11/1995 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20086G665 | List: |
| References | |
| NUDOCS 9507170046 | |
| Download: ML20086G670 (3) | |
Text
y,-
i
@KiQu
'4 j
'I UNITED' STATES '
-]'
[
NUCLEAR REGULATORY COMMISSION
- wAswinoTow, o.c, noses enei SAFETY' EVALUATION BY THE OFFICE OF' NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.117
)
TO FACILITY OPERATING LICENSE NO. NPF-49 i
NORTHEAST NUCLEAR ENERGY COMPPNY. ET AL.
NILLSTONE NUCLEAR POWER STATION. UllIT NO. 3 DOCKET NO. 50-423
1.0 INTRODUCTION
By letter dated March 29, 1995 the Kartheast Nuclear Energy Company (the licensee), submitted a request for changes to the Millstone Nuclear Power s
Str. tion, Unit No. 3 Technical Specifications (TSs) oertaining to rod drop time q
testing. The requested changes would amend TS 3.10.5 to allow more than one.-
control bank to be fully withdrawn from the core simultaneously in order to:
i conduct rod drop time response testing. This change would permit the licensee 1
to take advantage of a new improved rod drop computer installed during.the 1995 refueling outage. The new computer has the capability to measure the time responses of all the rods simultaneously.
The licensee is. requesting the'-
proposed TS changes in the hope that they will decrease the test time and the impact of the testing on the critical path activities during refueling j
outages.
2.0 EVALUATION During rod drop time testing, the shutdown margin requirements,-as specified.
in the proposed TS 3.10.5, will be met without crediting the withdrawn control i
rods. This requirement is necessary to provide a margin of safety in the K.,,
J the t;ewly fueled core.
I i
The licensee proposes to revise TS 3.10.5 to allow more than one control bank to be fully withdrawn from the core simultaneously in order to conduct rod drop time testing. However, the licensee proposes to add a requirement in TS 1
3.10.5 that provides an added margin of safety in K ' fore the rod drop time state of the new-core will not have been evaluated Ne, since the reactivity testing.
Specifically, the licensee proposes to add a requirement to.the 1
Limiting Condition for Operation (LCO) 3.10.5 that states:
"The SHUTDOWN i
MARGIN requirement of Section 3.1.1.1.2 shall be met without credit for withdrawn control rods." This requirement has the effect of changing the required subcritical state of. the reactor' system from K.,lnts out that during
<0.99 to a much lower value crediting boron only. Also, the licensee po the test, the additional available negative reactivity from the rods on receipt of a reactor trip signal will increase the'available shutdown margin significantly. -Furthermore, rod drop time testing with all banks out at one t
9507170046 950711 PDR ADOCK 05000423
. p PDR a
1
,n n
- - ~ +
~
4
+
- ~
8 7
L time is more realistic and in keeping with expected conditions, thus
- increasing confidence in the: applicability of the results to.the safety analysis.-
Current TSs permit the~ rod position indication system to be disabled for each control bank while the. rod drop test is performed. The proposed changes woula allow.the rod position indication system to be removed simultaneously from all the control and shutdown banks during the test.
It should be pointed out that-this system is not a safety system credited in the accident analyses..
l Consequently, its removal from all the banks will not degrade the safety system in any way.
Furthermore, the LC0 for TS 3.1.3.3 (rod position-indication operability) will be met, since the rod drop time test is initiated
- i by opening the reactor trip breakers. This test is performed in modes 3,4, and 5.
l The licensee a'ddressed the boron dilution accident, a primary concern for 1
modes 3,4, and 5.
'In the accident analysis, a minimum shutdown margin is 1
required (as specified in TS 3/4.1.1.1.2) allowing the operator 15 minutes 4
from the time of initiation of the shutdown margin monitor alarm to the total loss of shutdown margin.- In the upcoming and future reloads, the nuclear design report will contain the required minimum boron concentrations to meet-the shutdown margin provided in the TS during the rod. drop time testing.
]
Minimum boron concentrations will depend on the various combinations'of control.and shutdown banks withdrawn. Since the shutdown margin requirement of K.,, dilution accident, the accident analysis is not affected.less'than or equal to 0.9 boron The licensee analyzed other accidents postulated during shutdown that could be l
affected by this change (e.g., rod ejection and uncontrolled rod ' withdrawal-
)
from subcritical) and concluded that, since the case in which all rods are in-is the' limiting case for these accidents, this limiting case bounds the
- configuration established during the rod drop time test ~as allowed by this 1S change.. Consequently, established assumptions for these accidents remain unchanged, and the accident analysis is not affected.
In the submittal of March 29, 1995, the licensee also included two editorial.
changes to the bases section of TS 3.10.5.
Since these changes are editorial, they have no impact on safety, ihe staff reviewed the analyses performed by the licensee in support of the requested TS changes and finds them acceptable. The NRC staff has reviewed the reports submitted by the licensee for the continued operation of Millstone
. Unit 3 and concludes that the licensee suSmitted the appropriate material for Technical Specification changes pertaining to rod drop time testing. The staff reviewed the proposed TS changes and found them acceptable.
i i
p.-
' 3-i 3.0 ~
STATE CONSULTATION In accordance'with the Commission's regulations,'th'e Connecticut State official was notified of the proposed issuance of the amendment. The State official had no comments.
4.0-ENVIROPMENTAL CONSIDERATION
.i i
The amendment changes a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20. The NRC staff has determined that the amendment in"olves no significant increase in-the amounts, and no significant change in the types, i
of any effluents that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure.
The Commission has previously issued a proposed finding that the amendment' involves no significant hazards consideration, and there has been no i
public comment on such finding (60 FR 29880). Accordingly, the amendment i
meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).
Pursuant to 10 CFR 51.22(b) no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendment.
1 5.0 LQNCLU110N
-The Commission has concluded, based on the considerations' discussed above, t
that:
(1) there is reasonable assurance that' the health and safety of the public will not be endangered by operation in the proposed manner,-(2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendment will not be inimical to the common defense and security or to= the health and safety of the public.
Principal Contributor: A. Attard i
Date:
July 11, 1995 j
1
, -, - - - -