ML20032C202
| ML20032C202 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 11/02/1981 |
| From: | Lanpher L CALIFORNIA, STATE OF, HILL, CHRISTOPHER & PHILLIPS |
| To: | NRC OFFICE OF THE EXECUTIVE LEGAL DIRECTOR (OELD) |
| References | |
| ISSUANCES-OL, NUDOCS 8111090451 | |
| Download: ML20032C202 (16) | |
Text
. _,
~
6-
[ roun costsnacCS j L
UNITED STATES OF AMERICA 00tMETED NUCLEAR REGULATORY COMt!ISSION m RC ji NOV-4 Pii47 SEFORE THE ATOMIC SAFETY AND LICENSING BOARD OFFICE CF SECPIT/E CC s V'Q.Y?k T-
.. e >
In the Matter of
)
)
PACIFIC GAS AND ELECTRIC COMPANY )
Docket Nos. 50-275 0.L.
)
50-
~
(Diablo Canyon Nuclear Power
)
d//g Plant, Units Nos. 1 and 2)
)
p
'9k so,O o=
c G
'* \\
ISS/g $/
GOVERNOR BROWN'S RESPONSE
%, Id@
- M TO NRC STAFF'S REQUEST FOR ADMISSIONS g y/
h GovernorBrown'sresponsestotheNRCStaff'sRequest~p)
't,gi
/
for Admissions which were served on October 14, 1981, are as fol-2 lows:
PRESSURIZER HEATERS
)
Admission A-1:
Loss of Diablo Canyon's pressurizer heaters from i
normal operating conditions would cause the reactor system to slowly depressuri:e.
l Resoonse A-1:
i It is not possible to determine the answer to'this as not enough of the conditions of this hypothetical 4
event have beer. specified.
This is generally true as-
{.
suming continuation of power operation and no alternate Y g
/ / i 8111090451 811102 PDR ADOCK 05000275 O
4 operator actions.
If, however, a trip from full power is assumed, the operation of auxiliary feedwater, coolant pumps, high pres sure inj ection, and o the r sys tems capable of affecting the heat balance, as well as the decay heat generation rate, would have to be known to answer the re-ques t more comple tely.,
Admission A-2:
The reactor system must be depressurized to bring the Diablo Canyon Nuclear Power Plant to a cold shutdown condition.
Response A-2:
Admitted.
Admission A-3:
Depressurizing Diablo Canyon's reactor system from a hot standby condition to a cold shutdown condition can be accomplished without the pressurizer heaters.
Response A-3:
This is true, but it is not in accordance with normal prc.:edure nor is it a desirable method of operation.1/
Admission A-4:
Diablo Canyon's pressurizer heaters are not required to maintain the reactor system in a cold shutdown condition.
Resnonse A-4:
Admitted.
l/
PG5E Answer to J.
I. Interrogatory 45, October 26, 1981.
,_ L o
Admission A-5 :
In the July 29, 1980 letter to Al Schwencer (NRC) from L.M. Mills (TVA) transmitting the July 28, 1980 Sequoyah Nuclear Power Plant Unit 1 Special Startup Test Report, Test #3 concerning natural circulation with loss of pressurizer heaters demonstrated that natural circu-lation occurred with the pressurizer heaters de-energized.
Response A-5-.
This letter is not in our posression.
Admission A-6.
Operation of the pressurizer heaters is not assumed in the analysis of design basis events in the Diablo Can-yon FSAR.
Response A-6:
This is not a true statement as the FSAR clesrly identifies pressuri:er heater operation in a number of the accidents analyzed.
For example, the LOFTRAN model description states that pressurizer heaters are consider-ed.1/
Analyses of loss of electrical load and/or tur-bine trip events typical]y assume pressurizer heater operation. l Furthe, PGSE 's Emergency Operating Procedures include the use of pressurizer heaters.2/
1/
FSAR, 15.1-17, Amendment 10.
]/
FSAR, 15.2-33, Amendment 5.
3/
Answer to J.
I. Interrogatory 45, October 26, 1981 Admission A-7:
Operation of'Diablo Canyon's Pressurizer heaters is not required to maintain the reactor coolant pres-sure boundary.
Response A-7:
If the definition of operation is strictly limited to the function of adding thermal energy to the coolant system, this is true.
The pressurizer heaters must al-so maintain physical integrity for the reactor coolant pressure boundary to be maintained.
Admission A-8 :
Operation of Diablo Canyon's pressurizer heaters is not required for plant safety.
Response A-8:
Denied.
Plant safety may be affected by many things, not the least of which is to minimize the number of challenges.
to the total system integrity and to optimize the oper-ability and controllability of systems used in the mitigation or control of abnormal events.
The NRR Lessons Learned Task Force found that " maintenance of natural circulation capability is important to safety."1/
Pressurizer heaters are needed for this capability.
Substantiating this view was the NRC's TMI-2 investiga-
. tion team,which recommended the following:
1/
NUREG-0578, page A-2. -
l "The pressurizer heater system should be classified-as safety grade which would assure emergency powe-availability'and. pro-tection from failures duerto environmental-conditions." 1];
i
-1/
Memorandum for J.M..Allan, NRC, from R.D. Martin, NRC,
" Operations Team Recommendations", October-10, 1979, pg. 23.
PORV'S AND BLOCK VALVES Admission B-1:
Proper operation of block valves is not assumed i
in the analysis of any design basis event in the Diablo Lanyon FSAR.
Resnonse B-1:
This request is insufficiently precise to permit a direct response.
The approach used in the FSAR analysis is not to assume or evaluate proper operation of the block valves but to assume certain accident conditions and calculate the theoretical results.
For example, a block valve failure to close when the PORV s ticks open can create a small LOCA (one of the design basis events).
In the FSAR a small LOCA is simply assumed without identifying its cause or its migiga-tion.
In the instant example of a PORV s tuck open, mi.tigation of the small LOCA may be accomplished by closing the associated.
block valve.
Admission B-2:
Diablo Canyon's block valycs are not relied upon to pro-vide overpressure protection of the reactor sys tem for low temperature operation.
Response B-2:
f
{
This cannot be admitted since there are sequences where failures of the block valves would prevent operation of the PORV's.
Thus, block valve failure could prevent the _ _ _ - _ - _ - _ - _ _ _ _ _ _ _ - _ _ _ _ _
'use'of PORV's as a means of overpressure protection dur-ing low temperature operation.
The Applicant's response to NUREG-0578 (T" Lessons Learned) refers to both block valves and PORV'= 4.n regard to low temperature over-pressurizatic' protection.
(PGGE response to Short Term Lessons Learned, February 29, 1980, page III-B-13).
Admission B-3:
Operation of Diablo Canyon's block valves are not relied upon to shut down the reactor and maintain it in a safe shutdown condition.
Response B-3:
Although the normal procedures do not appear to call for use of the block valves or PORV's in this mode, there are conditions where they may be called upon to assist in maintaining the plant in a safe shutdown condition.
The TMI-2 accident and post-accident. mitigation is such an example.
Thus, the above statement cannot be admitted und'er all circumstances.
Admission B-4:
Proper operation of the PORV's is not assumed in the analysis of any design basis event in the Diablo Canyon FSAR.
Response B-4:
See response B-1.,
Admission B-5:
Diablo Canyon's PORV's are not relied upon to pro-vide overpressure protection of the reactor system for low temperature operation.
Response B-5:
See res-onse B-2.
4 Admission B-6:
Operation of Diablo Canyon 2s PORV's are not relied upon to shut down the reactor and maintain it in a safe shutdown condition.
Response B-6:
See response B-3.
Admission B-7:
Failure of a PORV to close coupled with the failure of the block valve to be closed.by the operator would not result in core damage provided the emergency coolant sys-tems and auxiliary feedwater system functioned as designed at the Diablo Canyon Nuclear Power Plant.
Response B-7:
Westinghouse alleges this to be the case.
- However, there was probably a similar confidence in the benign.
impact of PORV's and block valve at TMI-2 prior to the accident.
The statement may be true if all systems oper-ate-exactly as prescribed and there are no severe accident -,
conditions or multiple failures or operator erro, occurring.
Admission B-8:
The scenario in Admission #7 would result in.offsite doses much less than the guidelines of 10 C.F.R. 100 provided that the containment isolation system function-ed as designed at the Diablo Canyon Nuclear Power Plant.
Response B-8:
Assuming the isolation system works as designed and is not overridden by operators, then this is admitted.
See response B-7.
Admission B-9:
~
Failure of a PORV and block valve would not sig-nificantly affect the consequences of a large-break LOCA at the Diablo Canyon Nuclear Power' Plant.
Response B-9:
Admitted.
Admission B-10:
Failure of a PORV and block valve would not sig-nificantly affect the consequences of a spectrum of small-break LOCA events already analyzed by the Appli-cant for the Diablo Canyon Nuclear Power Plant.
Re sp ons_L;,B -10 :
This cannot be admitted since there'is the possi-bility of erroneous behavior of the pressurizer function, 1 i
.,..n
--,-n
-,-~-r
pressurizer level indication, and vessel level indica-tion during a small break LOCA where there-is_also a PORV/ block valve failure.
Operator action and, thus, system behavior in the light of such possibly mislead-ing information cannot be predicted with certainty.
Admission B-11:
Diablo Canyon's PORV's have s ccessfully completed the EPRI test program Response B-11:
Whereas samples of the PORV's used at Diablo have completed some parts of the testing successfully, data have not yet been provided or reviewed on the final re-sults of the EPRI tests and the results of analyses of Diablo-specific piping, supports, ins trumentation, and mounting configuration have also not been provided.
- Thus, this statement cannot be admitted Admission B-12:
Two of the three PORV's and the associated block 1
valves are connected tc redundant emergency power sup-plies at Diablo Canyon.
Response B-12:
Admitted.
Admission B-13:
Diablo Canyon's PORV's and the associated block
-valves have been qualified as seismic Class 1 components. - _.
Response'B-13:
The FSAR is vague on this point (FSAR section 3.2, Table 3.2-4, sheet 25 of 38), stating that parts of the relief valve piping are design Class I but that Reactor Coolant System Valves may be Design Class I or II.
PGSE has stated in the low power hearing that the valves are seismic Class I.
- Admission B-14:
Diablo Canyon's block valves associated with the PORV's have been qualified as Seismic Class I components.
Response B-14:
~
See response B-13.
Admission B-15:
Diablo Canyon's PORV's have been environmentally qualified.
Response B-15:
This statement is ambiguous in that the term "en-vironmentally qualified" is not defined.
The Applicant has submitted a response to NUREG-0588 (NRC Staff Interim Position on Environmental Qualification) and the NRC issued SER Supplement 15 to 1
document their review but neither document addresses the PORV and block valves.
Also, there is uncertainty as to the inclusion of-ATWS environment in testing and qualifi-cations completed to date..
Admission B-16:
Diablo Canyon's block valves associated with the PORV's have been environmentally qualified.
Resconse B-16:
See response B-15.
Admission B-17:
The NRC Staff concluded in NUREG-0460 "that the present liklihood of severe censequences arising from j
an ATWS event is acceptably small and presently there is no undue risk to the public from ATWS."
Resnonse B-17:
Although this statement may be found in NUREG-0460, it does not present their total findings, which include "the present worth of both the direct and indirect risk of such an lATWSl accident is between $4.5 and $8.5 bil-lion..." (see NUREG-0460, Vol. 1, page 92) and that PORV operation has an i.npact on the effects of an ATWS acci-dent (see NUREG-0460, Vol.
4, Appendix D).
Admission B-18:
ATWS is not a design basis event for Diablo Canyon and, therefore, it does not have to be protected against solely with safety grade equipment.
Response B-18:
ATWS was not included in the Diablo Canyon FSAR as a design basis event, but the latter half of the admission -.
statement is an opinion of the Applicant which is not necessarily shared by the Governor and certainly is not shared by the Affiant.
Admission B-19:
Power operated relief valves of the type utilized at Diablo Canyon were tested by b3RI for both steam and water flow.
Response B-19:
Admitted with the proviso that this does no t ex-tend to an admission of the adequacy and completeness of the EPRI results and the further proviso that the EPRI program is incomplete because it does not extend to as-sociated equipment, ins trume nta tion, controls, and sup-ports.
4 Admission B-20:
Block valves of the type utilized at Diablo Canyon were tested by EPRI at rated steam flow conditions.
Response B-20:
" Rated... flow" is ambiguous.
It is not clear if the " rated steam flow conditions" in the statement in-cludes the conditions of steam flow expected for a worst case accident, ATWS conditions, and varying conditions of steam quality (up to and including two phase flow).
The statement would suffice for the dry steam flow ex-pected at rated conditons for operation of the reactor (e.g. 2250 psia and approximately 545 F).
Admission B-21:
No inadequacy'in design or performance was identi-fied by EPRI for the PORV's utilized at Diablo Canyon -
as a result of'EPRI testing.
. Response B-21:
This cannot be admitted until the complete results are available and the Diablo-specific analysis is com-plete for piping and mounting configurations as well as valve performance.
The Applicant does not plan to sub-mit these results until July, 1982 (see 2/26/81 letter, P. Crane (PGSE) to Miraglia (NRC), page 3).
Admission B-22:
No inadequacy in design or performance was identi-fied by EPRI for the block valves utilized at Diablo Canyon as a result of EPRI testing.
Response B-22:
See response B-21.
..c Respectfully submitted, Byron S. Georgiou Legal Affairs Secretary Governor's Office State Capitol Sacramento, California 95814 h wts % ~ct L.- <-
G-
': L-L/c Herbert H. Brown Lawrence Coe Lanpher i
HILL, CHRISTOPHER AND PHILLIPS,-P.C.
1900 M Street, N.W.
Washington, D.C.
20036 Attorneys for Governor Edmund G.
Brown, Jr., of the State of California Dated:
November 2,_1981.
r f
i
-)S-
UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION EEFORE THE ATOMIC SAFETY AND LICENSING BOARD In the Matter of
)
)
PACIFIC GAS AND ELECTRIC COMPANY)
Docke t No. 50-2 75 0.L.
)
50-323 0.L.
(Diablo Canyon Nuclear Power
)
Plant, Unit Nos. 1 and 2)
)
.s AFFIDAVIT OF DALE G. BRIDENBAUGH, RICHARD B. HUBBARD, AND GREGORY C. MINOR FOR GOVERNOR EDMUND G. BROWN, JR.
DALE G. BRIDENBAUGH, RICHARD B. HUBBARD, AND GREGORY C.
MINOR, being duly sworn, do say under oath that I, the undersigned have assisted in preparing and reviewing responses of Governor E dmun d G. B rown, J r. to NRC Staff's Admissions Nos. Al-A8 and B1-B22.
Said answers are true and correet to the bes t of my knowledge and belie f.
k
{
n Dale G. Bridenb augh
/
$hY Richard B. Hubbard October 30, 1981 W
Subscribed and sworn to before me this 3d-r/ day o f der 1981.
1 orriCIAL SEAL t
.o_>-o-o o-o-oe CARLO r. CARALL!
&s g /da-1 %9 "u:w::r 4 g
4 Santa Clara County NOTARY PUBLIC l
u, commission eram oct. 5.1984 l
/d[i!M My cot: mission expires.