ML17263A484

Safety Evaluation Supporting Amend 57 to License DPR-18

ML17263A484
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Site:	Ginna
Issue date:	12/07/1993
From:	Office of Nuclear Reactor Regulation
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Download: ML17263A484 (11)

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0~*y4 UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555 0001 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 57 TO FACILITY OPERATING LICENSE NO.

DPR-18 ROCHESTER GAS AND ELECTRIC CORPORATION R.

E.

GINNA NUCLEAR POWER PLANT DOCKET NO. 50-244

1. 0 INTRODUCTION By letter dated December 17,

1992, as supplemented April 8, 1993, the Rochester Gas and Electric Corporation (the licensee) submitted a request for changes to the R.

E. Ginna Nuclear Power Plant Technical Specifications (TS).

The April 8, 1993, letter provided clarifying information that did not change the initial proposed no significant hazards consideration determination.

The requested changes would eliminate the provision of high concentration boric acid (20,000 ppm) to the safety injection (SI) system.

This source would be replaced by the refueling water storage tank (RWST) which has a boron conc'entration of 2000 ppm.

Physically, this would be implemented through a

valve lineup change where AC power is removed from SI suction valves 825A and B (from the RWST) in the open position and from valves

826A, B,

C, D, (from the boric acid storage tanks (BASTS)), in the closed position.,

This would enable the SI pumps to take suction from the RWST.

The BASTs would continue to be used in conjunction with the chemical volume and control system (CVCS) to provide changes in boron concentration, to serve as a source of concentrated boric acid for use in maintaining long-term subcriticality, and to provide redundant boration flow paths.

The current high concentration of boric acid requires that the BASTs system have heat tracing to prevent precipation of boron.

With a sufficient reduction in BAST concentration and the proximity of the BASTs to the ambient temperatures in the auxiliary building, it would be possible to eliminate the heat tracing and its associated TS operability requirements'he need for SI suction switchover from the BAST to the RWST during the injection phase would also be eliminated.

TS Table 3.2-l,has been added to provide minimum temperature requirements and minimum volumes for a range of BAST concentrations.

These volumes provide the necessary inventory to maintain the required shutdown margin in a cooldown from hot zero power to cold shutdown.

The licensee has added a provision to the TS which requires the capability of borating to a shutdown margin equivalent of 2.45X delta-k/k at cold shutdown conditions (68 'F) with no xenon.

This compensates for long-term xenon decay and temperature reduction and provides an adequate shutdown margin for all modes of operation, including cold shutdown.

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~ 2. 0 EVALUATION

2. 1 RWST as a source for SI; Boration in maintaining long-term subcriticality The steamline break (SLB) is the only design basis event that could be significantly affected by the proposed elimination of the high concentration BASTs as a safety-related source for reactivity control injection fluid.

Analyses of the SLB with a BAST boron concentration of 2000 ppm (i.e., the same concentration as the refueling water storage tank (RWST))

and 2 loops in service were submitted in the Reload Transition Safety Report (RTSR) dated December 20, 1983.

Utilizing the LOFTRAN code, these analyses considered a

double-ended rupture of a main steamline at hot zero power conditions, with and without offsite power available.

An analysis was also performed for steam release through a failed-open steam generator safety valve with 2 loops in service and offsite power available.

These analyses were based on the following conservative assumptions:

the most negative moderator temperature coefficient at end-of-life; the most reactive rod stuck in its fully withdrawn position; failure of one safety injection pump; and minimum shutdown margin equal to 1.8X delta-k/k.

The results of these analyses indicated that the departure from nucleate boiling (DNB) design basis continued to be met with the BAST boron concentration reduced to 2000 ppm.

The RTSR was approved by issuance of Amendment 61 dated Hay 1, 1984.

By letter dated October 16,

1985, the licensee submitted an amendment request to revise containment internal pressure limitations.

Because the SLB is the design basis event for the determination of maximum containment

pressure, the results of SLB analyses were included in this document.

These analyses were performed using LOFTRAN and considered the double-ended main steamline rupture and the failed-open safety valve events under similar assumptions described above for the RTSR analyses, including a

BAST boron concentration of 2000 ppm.

However, only one loop was assumed to be in service during cooldown since the analyses performed assuming two-loop operation were previously reviewed and

approved, as noted above.

Additionally, a minimum shutdown margin of 2.45N delta-k/k was assumed for one-loop operation.

The results indicated that the DNB design basis continued to be met at the reduced boron concentration.

The licensee has also evaluated the effect of the proposed reduction in boron concentration on loss-of-coolant accident (LOCA) related analyses.

For both the large-break and small-break LOCA, the proposed reduction has no impact on the results of the analyses of record because the codes employed for these analyses do not model reactor coolant system (RCS) boron concentration.

Concerning post-LOCA long term core cooling requirements, the licensee has performed calculations using a

BAST boron concentration of 2000 ppm and has determined that the core will remain subcritical, assuming all control rods out.

Additionally, the reduction in concentration will not adversely affect boron precipitation in the reactor vessel following boiling in the core since only an increase in concentration would produce an adverse effect.

With the RWST (at a concentration of 2000 ppm) replacing the BASTs as the source of safety injection coolant, boration of the RCS would occur through a

charging pump at a maximum rate of 60 gpm.

Concerning the rate at which negative reactivity is introduced by boration, the requirement is that this rate must be greater than the rate at which reactivity is added as a result of xenon decay.

The licensee's calculations have indicated that this requirement is met with a concentration of 2000 ppm at a charging flow rate of 60 gpm.

Concerning proposed TS Table 3.2-1, the licensee's calculations indicate that a margin exists between the minimum required volume of boric acid specified in the table for each boron concentration and the inventory necessary to maintain the required shutdown margin.

The shutdown requirement of 2.45X delta-k/k is based on cold shutdown (68 'F),

no xenon conditions, assuming single loop operation during cooldown.

This requirement is more conservative than the current TS value of 1X delta-k/k at a reference temperature of 200 'F.

Based on our review of the licensee's documentation, as described

above, we conclude that the licensee has adequately demonstrated that the BASTs can be eliminated as a safety-related source for safety injection coolant and replaced by the RWST, which has a boron concentration of 2000 ppm.

2.2 Containment Integrity SLB events are the only analyzed events which are significantly affected by a reduction in boron concentration.

The rate at which boron is introduced into the core following an in-containment steam line break affects the mass and energy release to the containment and thereby affects the peak containment pressure resulting from the event.

An analysis submitted by the licensee on October 16,

1985, indicated that for various size breaks, with failure of one containment spray pump, there was not enough margin to the containment pressure limit to permit a reduction in boron concentration.

Subsequently, by letter dated December 17,

1992, the licensee forwarded a new containment integrity analysis which supports a reduction in boron concentration to 2000 ppm.

The new analysis predicts a peak containment pressure of 60 psig (which is equal to the containment design pressure) for the limiting case of a 4.37 sq.ft. double-ended rupture at 30X power with a main steam line check valve failure.

Both the 1985 and 1992 analyses utilized the LOFTRAN and COCO codes.

The 1992 analysis eliminated a major conservatism of the earlier analysis, i.e., inconsistent assumptions regarding the availability of offsite power.

The 1985 analysis assumed that offsite power was available to run reactor coolant pumps during the break (a conservative assumption),

but that boron injection was delayed for emergency diesel startup and load sequencing (a

conflicting assumption).

The 1992 analysis also eliminated other unnecessary conservatisms with respect to the 1985 analysis.

These relate to reactivity feedback coefficients, feedwater flow rates, initial steam generator water level, safety injection flow rate, containment spray flow rate and timing and

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heat sink properties.

These changes are described in a supplemental letter dated April 8, 1993.

Elimination of excess conservatisms to support boron concentration reduction is consistent with Generic Letter 85-16, issued August 23, 1985.

In accordance with the review guidance of SRP 6.2. 1. 1, the staff performed an independent confirmatory CONTEMPT-LT analysis for peak containment pressure.

The staff's analysis confirmed that, using the licensee's mass and energy release data as input, the peak containment pressure does not exceed the containment design pressure.

A copy of the resulting pressure response curve is attached.

2.3 Changes to Ginna TS to support elimination of the BASTs TS 3.2.1 and 3.2.1.1 This proposed revision ensures that, during cold shutdown or refueling, any activities involving core alterations or positive reactivity changes will be suspended when no flow path for boric acid injection to the core is available.

Because this revision represents an added caution and is consistent with the latest approved version of the Westinghouse Standard Technical Specifications (STS),

Item 3. 1.2. 1, we find it acceptable.

TS 3.2.2 and 3.2.3 The proposed revision to TS 3.2.2 is consistent with the current TS 3.2.2 above cold shutdown for meeting CVCS boron injection flow path operability requirements to the extent of establishing two flow paths.

The volume and solution temperature requirements for the BASTs would be replaced by Table 3.2-1 requirements.

These proposed revisions are accepted based on the discussions in paragraphs

2. 1 and 2.2 above.

TS 3.2.4 The proposed revision applies when the reactor is above cold shutdown and only one of the two required boron injection flow paths to the RCS is operable.

The allowable outage time (AOT) for the inoperable path would be extended from 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> to 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.

This revision is consistent with the latest approved version of the Westinghouse

STS, Item 3. 1.2.2, and is justified based on the low probability of a design basis accident occurring during the inoperability period.

We find this revision acceptable.

The proposed revision to TS 3.2.4 also includes a provision requiring the capability to borate to a shutdown margin equivalent to at least 2.45X delta k/k at cold shutdown (68 'F) conditions with no xenon present.

This ensures that adequate shutdown margin is maintained for all modes of operation and is more conservative than the current TS value of IX delta-k/k at a reference temperature of 200 'F.

This revision is therefore accepted.

The proposed revision to TS 3.3. 1. lb applies to operability of the cold leg accumulators when system pressure exceeds 1600 psig.

A RCS hydro test exception would be added to this requirement.

The intent of this TS is to ensure availability of the accumulators during reactor operating modes at operating, hot shutdown and RCS temperature above 350 'F.

The hydro test at Ginna is conducted at an RCS temperature below 350 'F-and therefore the hydro test exception is acceptable.

TS 3.3.1.lc The proposed revision to TS 3.3. 1. Ic applies to SI pump operability.

The current TS r equires operability at or above a

RCS pressure and temperature of 1600 psig and 350 F, except during RCS hydro test performance.

The revision would delete the pressure requirement and retain only the temperature requirement.

Because the above pressure and temperature cannot be simultaneously established during normal operation, the temperature requirement alone would meet the intent of the TS and any ambiguity would be eliminated.

This revision is consistent with the latest approved version to the Westinghouse

STS, Item 3.5.2b, and is acceptable.

Deletion of the hydro test exception is consistent with the above discussion of TS 3.3. l.lb and is also acceptable.

TS 3.3.1.1i The proposed revision to TS 3.3. 1. li applies to A.C. power removal from the accumulator isolation valves in the open position when RCS pressure is above 1600 psig.

A hydro test exception would be added to this requirement and is acceptable as per the above discussion of TS 3.3. 1. lb.

TS 3.3.1.1 The proposed revision to TS 3.3. l.Ij is consistent with the requirements of TS 3.2 Bases (Page 3.3-14) where SI suction valves continue to be aligned with the RWST and therefore AC power is removed at or above RCS temperature of 350

'F.

The revisions are acceptable.

TS 3.3.1.2 This proposed revision applies to the operability conditions of the RWST when the reactor is above cold shutdown'nd would extend the AOT by 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />.

This revision is consistent with the latest approved version of the Westinghouse

STS, Item 3.5.5, and is acceptable.

TS 3.3.1.4 The proposed revision to TS 3.3. 1.4 would delete the pressure requirement and retain only the RCS temperature requirement less than 350 'F consistent with the above discussion of TS 3.3. l.lc.

The revision is acceptable.

TS 3.3.1.6 The proposed revision deletes this section.

Modification of TS 3.3. l.lj to allow one BAST to be out of service, provided minimum volume and solution temperature requirements are maintained before switchover to the

RWST, no longer applies.

TS 3.2 and 3.3 Bases Pa es 3.2-3 3.2-4 3.2-5 3.3-14 and 3.3-14a Our review of these bases sections finds them to be technically accurate, clearly written, and acceptable.

2.4 Administrative changes to the Ginna TSs TS 1.21 The proposed revision to TS 1.21 provides a definition for the term "Shutdown Margin" for the purposes of clarity.

The proposed revision is acceptable.

TS 3.2.5 The current TS 3.2.4 has been renumbered to TS 3.2.5 without any other changes.

We find this proposed revision acceptable.

TS Table 4.1-1 The proposed revision would add "Note 4" to the table for applicability to the BAST level instrumentation, only when the BAST is required to be operable.

We find the proposed revision acceptable.

TS Table 4.1-2 The proposed revision would add "Note 4" to the table for applicability of minimum frequency for BAST equipment and sampling tests, only when the BAST is required to be operable.

We find this proposed revision acceptable.

The proposed revision also would delete the "FSAR Section Reference" column.

This revision precludes conflicts with annual Updated Final Safety Analysis Report updates without a TS change to Table 4. 1-2, and would be consistent with other TS Section 4 Tables.

We find this proposed revision acceptable.

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V Based on the above evaluation of the licensees proposed TS revisions, we find these revisions to be acceptable.

3.0 STATE CONSULTATION

In accordance with the Commission's regulations, the New York State official was notified of the proposed issuance of the amendment.

The State official had no comments.

4. 0 ENVIRONMENTAL CONSIDERATION 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 involves no 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 the amendment involves no significant hazards consideration, and there has been no public comment on such finding (58 FR 52994).

Accordingly, the amendment 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.

5.0 CONCLUSION

The Commission has concluded, based on the considerations discussed

above, 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 Contributors:

H. Abelson W.

Long W. Jensen Date:

December 7,

1993

Attachment Limiting Main Steam Line Break 70 60 ressure 50 40 30.:':,':::::::-

NRC 20:::::::'::-::

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20 40 60 80 100 120 140 160 180 200 4/02/93 Time in sec

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