ML20118B134
| ML20118B134 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 09/21/1992 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20118B133 | List: |
| References | |
| NUDOCS 9209300192 | |
| Download: ML20118B134 (3) | |
Text
--.
.- - - -. - _ - - ~..
Hog?
I
+
f' UNITED STATES 3
Y'ei NUCLEAR HEGULATORY COMMISSION 8
o WASHINoTON, D C. 20%4 7
\\....*f l
SAFETY EVAL M ON BY THE OfflCf 0F NUCl[A3 REAll0R REGLATION PEL ATfD TO Af'ENDMENT N05.1.f6 AND 146 TO l
FAC))TY OPf RATifLG llCENSLMS. NPF-4 ARp_NPF-7 yRGlfRA_flElllC AND POWER COMPANY Q10 DOM!NION ELECTRIC C00ERATIE.
MRTH ANNA POWED ST ATION. _Ul((TS NO.1 AND No. 2 P0CKET NOS. 50__3_38 AND 10.-J1Q l.0 JFTRODUCTIO_fj l
By letter dated July 16, 1992, the Virginia Electric and Power Company (tl.e licensee) proposed a change to the Technical Specifications (TS) for the North Anna Power Station, Unit Nos. 1 and 2 (NA-l&2).
The proposed change would revise the wording to the NA-l&2 TS 5.4.2 for the reactor coolant system (RCS) l volume in the design features section of the TS.
The proposed char.ge would I
revise the description of the RCS volume from ".. 9957 10 cubic feet at a nominal Tavg of 525' f" to "...approximately 10,000 cubic feet at nominal operating conditions." Also, the proposed change to the Bases for TS 3/4.1.1.3 would chance the ph ase "...will circulate an equivalent reactor coolant system volume of 9957 cubic feet" to "...will circulate the Reactor Coolant System volume."
2.0 DISCUSSION 10 CFR 50.36 describes the purpose of the design features section in the TS.
Design features in the TS are tnose features of the facility which, if altered or modified, would have a significant effect en safety.
TS 5.4.2 does not meet this criterion as it is currently written.
NUREG-0452, " Standard Technical Specifications for Westinghouse Pressurized Water Reactors" Revision 4 (STS), provides guidance to licensees when preparing TS. One design feature specified in the STS is the RCS volume.
A calculated RCS volun.e was obtained f roni the reactor vendor and included in the NA-l&2 TS consistent with STS guidance.
However, that calculated volume is not used in accident analyses.
Rather, tFe transient system models used to perform accident analyses divide the RCS into component mass-energy cells for.
which volumes are specified.
The definition and volume of these mass-energy cells vary depending on the model used and the accident bebig analyzed. Thus, the methodology does not require that a single total RCS volume be specified as an accit.Dnt analysis basis and revising the current description would have l
no significant effect or safety.
0$00$339 PDR 4
.. -,, ~ _.,.
_,,,mm.,
_.~,,.,.m_._
.....,__,y w.,,,e..%.,.,
~~..,.~g.
,c.,.,
.,_,m.~,,
v l
l i
2 TS 5.4.2, as currently worded, is ambiguous.
It refers to a Tavg that is 5
significantly lower than normal operating ccaditions.
Also, citing an RCS volume at a lavg of 525' f provides insufficient information for meeting a tolerance of plus or minus 10 cubic feet.
Other parameters, such as system pressure and pressurizer temperature, are also required to calculate the volume to within 10 cubic feet.
Those parameters are not clearly de"ned since the cited Tavg is not based on normal operating conditions.
The description of the RCS volume in TS 5.4.2 is changed from ".. 9957 10 cubic feet at a nominal Tavg of $25' f" to "...approximately 10,000 cubic feet at nominal operating conditions." This is the RCS volume at nominal operating ccaditions rounded off to the nearest 1000 cubic feet.
The proposed revision states a nominal volun,e (i.e., to within 1.5%) and does not misrepresent the accuracy nor the operating temperature.
The change is consistent with the definition of design features in 10 CFR 50.36.
TS 3/4.1.1.3 requires the flow rate of reactor coo int through the RCS to be
The Bases for TS 3/4.1.1.3 state that the minimum flow rate of at least 3000 gpm provides adequate mixing, prevents stratification and ensures that reactivity changes will be gradual during boron concentration reductions in the RCt.
It j
e' then states that "...a flow rate of at least 3000 gpm will circulate an 1
equivalent RCS volume of 9957 cubic feet in approximately 30 minutes." This statement is changed to "...a flow rate of at least 3000 gpm will circulate 7
the Reactor Coolant System volume in approximately 30 minutes."
3.0 EVALUATIM a
ue proposed change to the NA-l&2 TS 5.4.2 does not Fave any adverse _ effect on
- safety, it specifies the RCS volume commensurate with the accuracy required for describing a design feature.
However, the proposed change preserves the intent of the design feature by assuring that a sigaificant RCS volume change would be identified and evaluated for potential safety significance.
- Also, accident analyses methodology does not require that a single total RCS volume be specified as an accident analyses basis.
Therefore, revising the current NA-l&2 TS description has no significant effect on safety.
Finally, the proposed change so the Bases of TS 3/4.1.1.3 does not have any adverse effect on safety.
R; vising the phrase does not alter the meaning _of the Pases and eliminates a potential conflict with the revised design features.
Based on all of the above, the staff finds the proposed change to the NA-l&2 TS acceptable.
4.0 STATE CONSULTATI@
in accordance with the Commission's regulations, the Virginia State official was notified of the proposed issuance of the amendment. -The State official I
had no comment.
I 3
j 1
8 t
r j
5.0 [HElRONMENTAL CONSIDERATION f
These amendments change a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CfR 1
Part 20. The NRC staff has determined that the amendments involve no l
significant increase in the amounts, and no significant change in the types, 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 these i-amendments involve no sinnificant hazards consideration and there has been nc pubic comment on such finding (57 FR 37574). Accordingly, these amendments meet the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).
Pursuant to 10 CFR Sl.22(b) no environmental impact statement or
{
environmental assessment need be prepared in connection with the issuance of the amendments.
l 6.0 CONCLVSION The Commission has concluded, based on the considerations discussed above, that:
(1) there is reasonable assbrance 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, i
and (3) the issuance of the amendments will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor:
L. Engle Date: September 21, 1992 i
l l
i i
i i
t i
l i
i i
,,,,-.._....__,_._,,,...-_,,,,,...__.._.._.,..__.-,_..,._-.-,,...___.,_.,__m,___.,,..
-